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Purpose: Nutrition is of paramount importance in critically ill trauma patients. However, adequate supply is difficult to achieve, as caloric requirements are unknown. This study investigated caloric requirements over time, based on indirect calorimetry, in critically ill trauma patients. Methods: Retrospective cohort study at a tertiary trauma center including critically ill trauma patients who underwent indirect calorimetry 2012–2019. Caloric requirements were assessed as resting energy expenditure (REE) during the intensive care unit stay up to 28 days and analyzed in patient-clustered linear regression analysis. Results: A total of 129 patients were included. Median REE per day was 2376 kcal. The caloric intake did not meet REE at any time with a median daily deficit of 1167 kcal. In univariable analysis, ISS was not significantly associated with REE over time (RC 0.03, p = 0.600). Multivariable analysis revealed a significant REE increase (RC 0.62, p < 0.001) and subsequent decrease (RC – 0.03, p < 0.001) over time. Age < 65 years (RC 2.07, p = 0.018), male sex (RC 4.38, p < 0.001), and BMI ≥ 35 kg/m2 (RC 6.94, p < 0.001) were identified as independent predictors for higher REE over time. Severe head trauma was associated with lower REE over time (RC – 2.10, p = 0.030). Conclusion: In critically ill trauma patients, caloric requirements significantly increased and subsequently decreased over time. Younger age, male sex and higher BMI were identified as independent predictors for higher caloric requirements, whereas severe head trauma was associated with lower caloric requirements over time. These results support the use of IC and will help to adjust nutritional support in critically ill trauma patients. [ABSTRACT FROM AUTHOR]

Background and Objectives: This study aimed to investigate the respiratory quotient (RQ) levels and its trend in the early postoperative period of patients with heart disease. Additionally, we explored factors influencing RQ and evaluated the predictive capabilities of RQ and lactic acid for various outcomes., Methods and Study Design: In this prospective observational study, participants included were heart disease patients aged 18-80 years who underwent elective open-heart surgery and were subsequently admitted to the cardiothoracic surgery ICU post-operation. Indirect calorimetry (IC) measurements were conducted on patients dur-ing the first three days after surgery to assess their RQ levels. Clinical data, including personal information, postoperative characteristics, and duration of surgery, were documented based on the patient's medical history., Results: In this study, 135 patients, of whom 57.04% were male, underwent a total of 247 IC measurements following cardiac surgery. On the first, second, and third days of admission to the ICU, the RQ values were 0.77±0.09, 0.80±0.07, and 0.78±0.05, respectively. The ROC curve analysis showed that on the first day of admission to the ICU, RQ was a better predictor of prolonged mechanical ventilation, LOS in ICU, and LOS in hospital compared to lactate level. However, on the second day of ICU admission, neither RQ nor lactate level could predict longer durations of mechanical ventilation, LOS in ICU, and LOS in hospital., Conclusions: RQ may serve as a potential predictor for LOS in patients after cardiac surgery., Competing Interests: The authors declare no conflict of interest

Background & Aims: Various factors may cause significant daily variations in energy expenditure in and between critically patients. This nested, prospective study (ClinicalTrials.gov Identifier: NCT04099108) in a predominantly trauma surgical ICU, aimed to determine the course of measured energy expenditure over the first 10 days of critical illness, and to identify factors contributing to energy expenditure., Methods: Indirect calorimetry was performed on alternate days from ICU Day 3 ± 1 until Day 10 ± 1. The mean daily measured energy expenditure, respiratory quotient and total energy delivery as a percentage of measured energy expenditure were modelled using linear mixed regression with two fractional polynomial terms to accommodate non-linear responses over time., Results: Fifty ICU patients (mean age 36.9 ± 11.8 years, Acute Physiology and Chronic Health Evaluation (APACHE II) 13.5 ± 6.6, Sequential Organ Failure Assessment (SOFA) 4.5 ± 3.2) were included. Mean body mass index (BMI) was 24.8 ± 4.0 kg/m 2 and mean ventilation duration 7.7 ± 2.7 days. Mean daily measured energy expenditure showed a significant non-linear response (p = 0.006) increasing over the first 4 days peaking on day 5 and then plateauing. Mean daily respiratory quotient increased over the first 7 days, thereafter plateauing with a slight downward trend from day 8 despite a progressive increase in total energy delivery as a percentage of measured energy expenditure. Mean daily measured energy expenditure was significantly lower in the early than in the late acute phases (p = 0.024), whereas the late- and post-acute phases were similar. Age, sex and BMI significantly influenced measured energy expenditure., Conclusion: Measured energy expenditure showed a significant non-linear response over the first 10 days in ICU, increasing over the first 4 days peaking on day 5 then plateauing. The observed variability highlights the complexity of managing critically ill patients and the importance of personalised nutrition therapy. Additionally, the observed trend with a peak in measured energy expenditure around day five could inform timing and strategies for nutritional intervention in this patient cohort., Competing Interests: Declaration of competing interest The authors report no conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background and Aims: Tailoring nutrition to measured energy expenditure (EE) and provision of adequate protein amounts, is considered gold standard for critically ill patients. There are currently no recommendations to measure specific substrate utilization or to adapt nutrition accordingly., Methods: In this retrospective longitudinal study, we analyzed results of 316 simultaneous measurements of indirect calorimetry (IC) and urinary urea nitrogen (UUN) in 191 mechanically ventilated, critically ill patients, admitted to the surgical intensive care unit (SICU) in a tertiary medical center. We calculated substrate utilization, compared it to administered nutrition, investigated factors that may influence it and tested the added value of routine UUN measurements over IC alone., Results: The mean total EE, measured using the indirect calorimetry module, was 1600 ± 451 kcal/day The mean daily fat, carbohydrates and protein oxidation were 118.3 ± 63.9 g, 53.3 ± 114.1 g and 64.7 ± 36.0 g, respectively, accounting for 68.8 % ± 31.4 %, 14.2 % ± 29.6 % and 17.0 % ± 8.6 % of the total EE. Fasting and noradrenaline administration were the only factors that influenced substrate utilization, resulting in higher fat and lower carbohydrate utilization (p < 0.045 for all). There were significant differences between percentage of substrate utilization and supply, with average differences of +28.5 % for fat, -38 % for carbohydrates and +1.9 % for protein (p < 0.006 for all)., Conclusions: SICU patients demonstrated very high fat utilization and lower than expected carbohydrate utilization, that differed significantly from amounts supplied. Further prospective studies are needed to elucidate the clinical impact of these findings., Competing Interests: Declaration of competing interest All authors declare no conflicts of interest., (Copyright © 2024 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.)

Objective: Central venous-arterial PCO 2 to arterial-central venous O 2 content ratio (P cv-a CO 2 /C a-cv O 2 ) is commonly used as a surrogate for respiratory quotient (RQ) and tissue oxygenation. Although P cv-a CO 2 /C a-cv O 2 might be associated with hyperlactatemia and outcome, neither the interchangeability with RQ nor the correlation with conclusive variables of anaerobic metabolism has never been demonstrated in septic shock. Our goal was to compare P cv-a CO 2 /C a-cv O 2 and RQ in patients with septic shock., Design: Prospective, observational study., Setting: Two adult ICUs., Patients: Forty-seven patients with septic shock on mechanical ventilation with stable respiratory settings and vasopressor dose after initial resuscitation., Interventions: None., Main Variables of Interest: We measured arterial and central venous gases, Hb, and O 2 Hb. P cv-a CO 2 /C a-cv O 2 and the ratio of central venous-arterial CO 2 content to arterial-central venous O 2 content (C cv-a CO 2 /C a-cv O 2 ) were calculated. RQ was determined by indirect calorimetry., Results: P cv-a CO 2 /C a-cv O 2 and C cv-a CO 2 /C a-cv O 2 were not correlated with RQ (R 2 = 0.01, P = 0.50 and R 2 = 0.01, P = 0.58, respectively), showing large bias and wide 95 % limits of agreement with RQ (1.09, -1.10-3.27 and 0.42, -1.53-2.37). A multiple linear regression model showed Hb, and central venous PCO 2 and O 2 Hb, but not RQ, as P cv-a CO 2 /C a-cv O 2 determinants (R 2 = 0.36, P = 0.0007)., Conclusions: In patients with septic shock, P cv-a CO 2 /C a-cv O 2 did not correlate with RQ and was mainly determined by factors that modify the dissociation of CO 2 from Hb. P cv-a CO 2 /C a-cv O 2 seems to be a poor surrogate for RQ; therefore, its values should be interpreted with caution., (Copyright © 2024 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.)

Objective: The objectives of the study were (1) to assess whether resting energy expenditure (REE) equations have comparable validity for adolescents with overweight/obesity vs. adolescents with healthy weight and (2) to examine determinants of measured REE in adolescents with overweight/obesity vs. adolescents with healthy weight. Methods: Ten equations were used to predict REE for 109 adolescents (70% males; 36.7% with overweight/obesity); 95% equivalence testing was used to assess how well each equation agreed with the criterion measure of indirect calorimetry. Linear regression models were fitted to examine how much REE variance was accounted for by age, sex, race, fat-free mass (FFM), and fat mass. Results: For adolescents with healthy weight, all ten equations were significantly equivalent to the criterion measure within ±8.4% ( p < 0.05), whereas for participants with overweight/obesity, only three equations were equivalent within the same range ( p < 0.05). Controlling for age, sex, race, fat mass, and FFM accounted for 74% of REE variance. FFM explained the greatest amount (26%) of variance in REE, while weight status itself explained an additional 22%. Conclusions: Prediction equations tend to be more accurate for adolescents with healthy weight than adolescents with overweight/obesity unless the original sample specifically included participants with overweight/obesity. Determinants of REE are similar regardless of weight status.

Purpose: Following short-term weight loss, the energetic cost of transport decreases and exercise efficiency increases. Whether changes persist during long-term weight maintenance is unknown., Methods: We compared walking economy and exercise efficiency in weight loss maintainers (WLM, maintaining ≥13.6 kg weight loss for ≥1 year), controls without obesity (NC, BMI similar to current BMI of WLM), and controls with overweight/obesity (OC, BMI similar to pre-weight loss BMI of WLM). Energy expenditure (EE) and respiratory quotient were measured using indirect calorimetry at rest, while standing, and during treadmill walking. Gross and net energetic cost of transport (J/kg/m) was measured during level treadmill walking at 0.75, 1.12, and 1.52 m/s. Gross, net, and delta efficiency (%) were measured during inclined treadmill walking (2 %, 4 %, and 6 % grade) and a constant speed (1.12 m/s)., Results: WLM (n = 32, BMI: 23.8 ± 2.3 kg/m 2 ) and NC (n = 28, BMI: 22.7 ± 1.6 kg/m 2 ) had significantly lower EE (kJ/min) compared to OC (n = 26, BMI: 33.0 ± 4.5 kg/m 2 ) during rest, standing, and walking (p < 0.01). Net energetic cost of transport was significantly lower in WLM compared to OC at 1.12 and 1.52 m/s (p < 0.05). Net efficiency was significantly greater in WLM compared to OC while walking (p ≤ 0.05). There were no significant differences between WLM and NC for any measures of economy or efficiency., Conclusion: WLM had lower walking economy and greater walking efficiency compared to OC, but there were no differences between WLM and NC. Thus, individuals maintaining significant weight loss may be successful with long-term weight loss, in part, due to resistance against adaptive reductions in walking energetics., Competing Interests: Declaration of competing interest All authors have no conflicts to disclose., (Copyright © 2024. Published by Elsevier Inc.)

Background/Objective: Weight loss is associated with reductions in resting energy expenditure (REE), which are impacted by changes in body composition following sleeve gastrectomy (SG). Current data regarding changes in measured REE (mREE) and metabolic adaptation in adolescents after SG are limited. We evaluated changes in mREE, metabolic adaptation, and body composition in youths after SG vs. non-surgical (NS) controls over two years. Methods: Youths 14-22 years old undergoing SG ( n = 24) and NS controls with severe obesity ( n = 28) were recruited. mREE was determined using indirect calorimetry. Predicted REE (pREE) was calculated using regression equation derived from baseline data of our cohort and used to calculate pREE at follow up. Metabolic adaptation was calculated as mREE - pREE. We normalized REE to fat-free mass (FFM) and total body weight (TBW). Dual energy X-ray absorptiometry was used to measure body composition. Measurements were performed at baseline and two-years. Results: Baseline age, sex, and BMI were similar between groups. Greater decreases in BMI in SG vs. NS (-12.4 (-14.4, -9.8) vs. 2.2 (0.3, 3.5) kg/m 2 , p < 0.0001) and within-group decreases in mREE (401.0 ± 69.5 kcal/d; p < 0.0001) in SG were seen. mREE/FFM decreased within the SG group ( p = 0.006), the two-year change in mREE/FFM and mREE/TBW did not differ between groups ( p = 0.14 and 0.24). There was no metabolic adaptation within SG. Conclusions: Despite significant decreases in BMI after SG in youths, no metabolic adaptation was present at two years. This implies that by two years, metabolism has reached a steady state and weight changes after this should be addressed in an unbiased way.

It is unclear if running power (RP) estimated by the Stryd footpod device maintains its linear relationship to metabolic power (W MET ) when switching between training and racing shoe types. This study determined if RP estimated by the Stryd footpod and its other spatiotemporal metrics reflect the improvement (decrease) in W MET when wearing high-performance racing shoes (HPRS; Nike AlphaFly Next%) compared to control training shoes (CTS; Nike Revolution 5). Fourteen well-trained runners completed two treadmill tests: Absolute Velocity Running Test (AVRT; 11.3-14.5 km·hr -1 ) and Relative Velocity Running Test (RVRT; 55-75% VO 2MAX ). W MET was determined with indirect calorimetry. RP was not significantly different between shoe types ( p  > 0.432) during the AVRT, but W MET was ~5% lower in HPRS ( p  < 0.001). During the RVRT, participants ran ~6% faster and at ~6% higher RP (both, p  < 0.001) in HPRS for the same W MET ( p  = 0.869). Linear mixed models confirmed W MET was ~5% lower in HPRS for a given RP ( p  < 0.001). Still, RP and W MET were strongly related within shoe types ( p  < 0.001, conditional- R 2  = 0.982, SEE = 2.57%). Form power ratio and ground contact time correlated with energetic cost ( p  < 0.011) but did not fully reflect the influence of shoe type. Therefore, runners should account for their shoe type when using RP to indicate W MET between training and racing.

Introduction: Resting energy expenditure (REE) may fluctuate during the menstrual cycle (MC), due to the physiological effects of estradiol (E2) and progesterone. This study examined changes in REE and metabolic hormones (leptin, ghrelin, thyroid hormones), and dietary intake in two hormonally distinct groups, naturally menstruating women (NoOC) and women using monophasic combined oral contraceptives (COC)., Methods: Measurements included REE by indirect calorimetry, body composition by bioimpedance, and blood samples for hormone analysis in the early follicular and midluteal phases of the MC in the NoOC group ( n = 38) or the active and inactive phases of the COC cycle (COC; n = 19). Participants recorded their food intake for 3 d after measurements. A secondary analysis was completed for the NoOC group without REE outliers (difference between measurements >1.5 × interquartile range, n = 4)., Results: In the NoOC group, luteal phase REE was 40 kcal higher than follicular phase REE (95% confidence interval (CI), -2 to 82 kcal·d -1 , d = 0.20, P = 0.061). Leptin ( d = 0.35, P < 0.001), triiodothyronine (T3; d = 0.26, P = 0.05), and fat intake ( d = 0.48, P = 0.027) were higher, and thyroxine ( d = 0.21, P = 0.041) was lower in the luteal phase. After excluding outliers, REE was 44 kcal higher in the luteal phase than in the follicular phase (95% CI, 12-76 kcal·d -1 , d = 0.22, P = 0.007). In the COC group, the mean difference in REE was -2 kcal (95% CI, -82 to 79 kcal·d -1 ) between active and inactive phases, whereas T3 was higher in the inactive phase ( d = 0.01, P = 0.037)., Conclusions: REE increases only slightly from the follicular to the luteal phase but remains unchanged between COC phases. Increases in T3, leptin, and fat intake during the luteal phase might echo metabolic fluctuations that parallel female sex hormones during the MC., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American College of Sports Medicine.)

Background & Aims: We previously reported in the ELY prospective study that increased resting energy expenditure (REE) - so-called hypermetabolism - worsened tumor response, 6-month progression-free (PFS) and overall survival (OS) in metastatic non-small cell lung cancer (mNSCLC) patients treated with immune checkpoint inhibitors (ICI). Here, we investigated the effect of caloric coverage on the sensitivity to ICI., Methods: We retrospectively analysed a multicentric database of mNSCLC patients treated with ICI. All patients had a baseline nutritional assessment including REE measured with indirect calorimetry and a dietitian estimation of food intakes. Measured/theoretical REE ≥110% defined hypermetabolism. Intakes ≥90% of estimated needs defined caloric coverage. The primary endpoint was PFS. Secondary endpoints included response rate and OS., Results: Among 162 patients, 84 (51.9%) were normometabolic, and 78 (48.1%) hypermetabolic. In hypermetabolic patients, 40 (51.3%) met their caloric needs (group A) while 38 (48.7%) did not (group B). Median PFS was 4.3 vs. 1.9 months in groups A and B, respectively (HR: 0.49, 95%CI [0.31-0.80], p = 0.004). The PFS achieved in the group A and in normometabolic patients were similar (HR: 0.99, 95%CI [0.65-1.51], p = 0.95). In multivariate analysis, caloric coverage was independently associated with improved PFS in hypermetabolic patients (HR: 0.56, 95%CI [0.31-0.99], p = 0.048). Among hypermetabolic patients, the median OS was higher in the group A (HR: 0.58, 95%CI [0.35-0.95], p = 0.03)., Conclusion: Energy supply is a critical determinant of the sensitivity to ICI in NSCLC patients. A randomized study to evaluate the benefit of early nutritional intervention is warranted., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Manuela Tiako Meyo, Elizabeth Fabre, Marie Wislez, François Goldwasser: Honoraria from BMS. Elizabeth Fabre, Marie Wislez, Jérôme Alexandre: Honoraria from MSD. François Goldwasser; Honoraria from Nutritia, Fresinus, Baxter. The other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: Patients who have sustained extensive burns frequently exhibit substantial damage to skeletal muscle and associated complications. The rehabilitation of these patients can be challenging due to the nature of the injury and the subsequent complications. Nevertheless, there is a possibility that functional proprioceptive stimulation (illusory movements) may facilitate effective rehabilitation in patients with limited physiotherapy options. Nevertheless, this approach has yet to be tested in patients with burn injuries., Material and Methodology: A prospective, randomised, crossover trial was conducted at a burn centre in a tertiary teaching hospital. The objective was to assess the effects of illusory movements on energy metabolism, insulin sensitivity, and skeletal muscle biology in adult critically ill patients with deep burns covering 30 % or more of the total body surface area. Two 30-minute daily sessions of functional proprioceptive stimulation were administered in addition to the standard physical therapy or physical activity regimen. Subsequently, the patients proceeded to the next stage of the trial, which involved a two-week crossover period., Measurements and Main Results: Daily indirect calorimetry and calculation of nitrogen balance. Skeletal muscle biopsies from vastus lateralis for high resolution respirometry and euglycemic clamps to assess whole body glucose disposal were performed three times: at baseline and then fortnightly after each intervention period. The intervention was feasible and well tolerated in both early and late stages of burn disease. It did not change energy expenditure (mean change -33 [95 % CI: -292;+227] kcal .24 h -1 , p = 0.79), nitrogen balance (+2.0 [95 % CI: -3.1;+7.1] g N .1.73 m -2 BSA .24 h -1 ), or insulin sensitivity (mean change of insulin-mediated glucose disposal -0.33 [95 % CI: -1.18;+0.53] mmol.h -1 ). At the cellular level, the intervention increased the capacity of mitochondria to synthesize ATP by aerobic phosphorylation and tended to increase mitochondrial coupling. Functional capacities of fatty acid oxidation and electron transfer chain complexes I, II, and IV were unaffected., Conclusions: Compared to physical therapy alone, two daily sessions of functional proprioceptive stimulation in addition to usual physical therapy in patients with extensive burns did not change energy expenditure, insulin sensitivity, nitrogen balance, or energy substrate oxidation. At cellular level, the intervention improved the capacity of aerobic phosphorylation in skeletal muscle mitochondria. Clinical effects remain to be demonstrated in adequately powered trials., Competing Interests: Declaration of Competing Interest There was no industry involvement in any aspect of this investigator-initiated trial. The authors have declared that they have no potential conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose Nutritional therapy in the intensive care unit is an essential factor for patient progress. The purpose of this study was to compare resting energy expenditure (REE) calculated by prediction equations (PEs) to the REE measured by indirect calorimetry (IC) in trauma patients. Methods Patients admitted to the trauma intensive care unit who received mechanical ventilation between January and December 2015 were enrolled. REE was measured by IC (CCM Express, MGC Diagnostics) and calculated by the following PEs: Harris-Benedict, Fleisch, Robertson and Reid, Ireton-Jones, and the maximum value (25 kcal/kg/ day) of the European Society for Clinical Nutrition and Metabolism (ESPEN). All patients were ventilated at a fraction of inspired oxygen (FiO2) below 60%. Results Of the 31 patients included in this study, 24 (77.4%) were men and seven (22.6%) were women. The mean age of the patients was 49.7±13.2 years, their mean weight was 68.1±9.6 kg, and their mean Injury Severity Score was 26.1±11.3. The mean respiratory quotient on IC was 0.93±0.19, and their mean FiO2 was 38.72%±6.97%. The mean REE measured by IC was 2,146±444.36 kcal/day, and the mean REE values calculated by the PEs were 1,509.39±205.34 kcal/day by the Harris and Benedict equation, 1,509.39±154.33 kcal/day by the Fleisch equation, and 1,443.39±159.61 kcal/day by the Robertson and Reid equation. The Ireton-Jones equation yielded a higher value (2,278.90±202.35 kcal/ day), which was not significantly different from the value measured using IC (p=0.53). The ESPEN maximum value (1,704.03±449.36 kcal/day) was lower, but this difference was likewise not significant (p=0.127). Conclusions The REE measured by IC was somewhat higher than that calculated using PEs. Further studies are needed to determine the proper nutritional support for trauma patients.

Human studies linking metabolism with organism-wide physiologic function have been challenged by confounding, adherence, and precisionHere, we united physiologic and molecular phenotypes of metabolism during controlled dietary intervention to understand integrated metabolic-physiologic responses to nutrition. In an inpatient study of individuals who underwent serial 24-hour metabolic chamber experiments (indirect calorimetry) and metabolite profiling, we mapped a human metabolome onto substrate oxidation rates and energy expenditure across up to 7 dietary conditions (energy balance, fasting, multiple 200% caloric excess overfeeding of varying fat, protein, and carbohydrate composition). Diets exhibiting greater fat oxidation (e.g., fasting, high-fat) were associated with changes in metabolites within pathways of mitochondrial β-oxidation, ketogenesis, adipose tissue fatty acid liberation, and/or multiple anapleurotic substrates for tricarboxylic acid cycle flux, with inverse associations for diets with greater carbohydrate availability. Changes in each of these metabolite classes were strongly related to 24-hour respiratory quotient (RQ) and substrate oxidation rates (e.g., acylcarnitines related to lower 24-hour RQ and higher 24-hour lipid oxidation), underscoring links between substrate availability, physiology, and metabolism in humans. Physiologic responses to diet determined by gold-standard human metabolic chambers are strongly coordinated with biologically consistent, interconnected metabolic pathways encoded in the metabolome.

Objectives: Engaging in dance of various styles confers health benefits among adults; however, additional studies on free-form dancing are needed to quantify its intensity and advance research on dance and health. This study characterized the absolute and relative physical activity (PA) intensities of solo, free-form dancing at self-determined moderate and vigorous intensities in adults., Method: Participants (N = 48) ages 18 to 83 years old, with 0 to 56 years of dance training experience, engaged in 5-minute free-form dance bouts at respectively self-determined moderate and vigorous intensities, both with and without music. Absolute intensity was measured during bouts using indirect calorimetry (metabolic equivalents; METs = [Formula: see text]O2 ml·kg-1·min-1/3.5). Relative intensity was measured by ratings of perceived exertion (Borg scale) and heart rate. Linear mixed effects models were used to assess the relationship between absolute and relative intensity metrics and model covariates., Results: On average, the relative intensity of self-determined moderate-to-vigorous intensity dancing, with and without music, was 76% of the age-predicted maximal heart rate; 74% of the heart rate reserve (HRR); and 13 on the Borg scale. By measure of %HRR, all adults reached at least a moderate PA intensity across all dance bouts. The mean absolute intensity of self-determined moderate intensity free-form dancing without music was 5.6 METs, and the presence of music (β = 0.6) and the intention to dance at a vigorous intensity (β = 1.1) were both significantly positively associated with METs, as participants engaged in free-form dance; METs were significantly inversely associated with age (β = -0.05) and BMI (β = -0.10)., Conclusions: When characterized using HRR, engaging in free-form dance at self-determined moderate-to-vigorous PA intensities provided a sufficient stimulus for all adults to reach a moderate PA intensity, which provides evidence that dancing however one wishes at such perceived intensities may support adults in accumulating the recommended weekly dose of 3150 minutes of moderate intensity PA., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Aston K. McCullough. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

It is unknown whether changes in lactate concentration produced by different situations (e.g., glycogen depletion or heat) modify fat oxidation. If confirmed, we could determine a dose-response relationship between lactate and fat. The aim of this study was to determine whether changes in lactate concentration (due to glycogen depletion or heat) alter fat oxidation during exercise. 11 males and eight females performed an incremental exercise test under three situations: control, glycogen depletion, and heat. At rest, in the last minute of each step and immediately post-exhaustion, lactate was analyzed and fat oxidation was estimated by indirect calorimetry. Lactate concentration was inversely associated with fat oxidation in the three aforementioned situations (r > 0.88 and p < 0.05). The highest lactate concentration was found in the heat situation, followed by the control situation, and finally the glycogen depletion situation (all p < 0.05). The opposite was found for fat oxidation, with the highest fat oxidation found in the glycogen depletion situation, followed by the control situation, and finally the heat situation (all p < 0.05). There is no association between the changes in lactate concentration between situations at each intensity and the changes in fat oxidation between situations at each intensity in males or females (p > 0.05). In conclusion, lactatemia is strongly and inversely associated with fat oxidation under the three different situations. Furthermore, the lowest lactate concentrations were accompanied by the highest fat oxidations in the glycogen depletion situation, whereas the highest lactate concentrations were accompanied by the lowest fat oxidations in the heat situation., (© 2024 The Author(s). European Journal of Sport Science published by Wiley‐VCH GmbH on behalf of European College of Sport Science.)

Running economy is an important determinant of endurance running performance, yet insights into characteristics contributing to its inter-individual variability remain limited. Although slow-twitch muscle fibers are more energy-efficient than fast-twitch fibers during the (near-)isometric contractions common during submaximal running, current literature lacks a consensus on whether a relationship between muscle fiber-type distribution and running economy exists. This study aims to resolve the ongoing debate by addressing potential confounding factors often overlooked in prior research, such as the effect of different running speeds, the homogeneity of investigated groups, and the potential impact of the adopted running gait. We selected two groups with predetermined distinct muscle fiber-type distribution in their triceps surae muscle by measurement of carnosine via 1 H-MRS, one predominantly slow (ST; n = 11; carnosine z-score = -1.31) and the other predominantly fast (FT; n = 10; z-score = 0.83). Across a range of running speeds (2-4 m/s), we measured running economy (W/kg) through indirect calorimetry, along with running kinematics, kinetics and muscle activity of the lower limb. The ST-group exhibited, on average, 7.8% better running economy than the FT-group (p = 0.01) and this difference was consistent across speeds. Both groups demonstrated almost identical kinematics, kinetics, and muscle activity patterns across submaximal running speeds. Overall, our findings indicate that distinct muscle fiber-type distribution explains some of the observed variability in running economy, for which a predominance of energy-efficient slow-twitch fibers appear beneficial. In contrast, muscle fiber-type distribution does not affect running gait substantially., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: This study aims to examine the relationship between resting vagal-related heart rate variability (HRV) parameters and heart rate (HR) with resting metabolic rate (RMR) and respiratory exchange ratio (RER) in young adults., Methods: A total of 74 young adults (22 ± 2 years old, 51 women) were included in this cross-sectional study. HRV was assessed using a HR monitor, whereas RMR and RER were determined by indirect calorimetry., Results: Linear regression analyses showed a positive association between HR and RER in women (standardized β = 0.384, p = 0.008), while negative associations were observed between vagal-related HRV parameters and RER in women (β ranged from -0.262 to -0.254, all p ≤ 0.042). No significant association was found between the abovementioned physiological parameters in men., Conclusion: Here, we show that HR is positively associated with RER in young women but not in men, while vagal-related HRV parameters are inversely related to RMR, therefore suggesting a potential sexual dimorphism between cardiac rhythm and its relationship with markers of cardiometabolic health status., Trial Registration: ClinicalTrials.gov identifier: NCT02365129., (© 2024 The Author(s). American Journal of Human Biology published by Wiley Periodicals LLC.)

Background: Energy expenditure (EE) in patients with aneurysmal subarachnoid hemorrhage (SAH) may differ from other intracranial pathologies, such as intracerebral hemorrhage (ICH) or traumatic brain injury (TBI), due to an activation of the sympathetic nervous system. Indirect calorimetry (IC) is recommended, but is not always available. We study EE, catabolism, and metabolic stress in patients with SAH, TBI, ICH, and sepsis as controls., Methods: A prospective observational study was conducted in the intensive care units of the University Medical Center Hamburg-Eppendorf, Germany. IC was used to measure EE on days 2-3, 5-7, and 10-15 post-admission. Urinary catecholamines, metabolites, and urine urea were also measured. Statistical analysis included t -tests, Chi-square tests, and generalized mixed models., Results: We included 110 patients-43 SAH patients (13 with the surgical securing of the aneurysm and 30 with coil embolization of the aneurysm), 22 TBI patients, 23 ICH patients, and 22 controls. The generalized linear mixed model analysis for groups and timepoints including age, height, and weight as covariates revealed a significantly lower EE at timepoint 1 for ICH versus SAH-interventional ( p = 0.003) and versus the control ( p = 0.004), as well as at timepoint 2 for ICH versus SAH-interventional ( p = 0.002) and versus SAH-surgical ( p = 0.013) with a lower EE in ICH patients. No significant differences between groups were found for EE at the other timepoints, or concerning urine urea and measurements of catecholamines in urine., Conclusions: In patients with SAH, ICH, and TBI, no meaningful differences in EE were detected compared to septic critically ill patients, except for a lower EE in ICH patients in the early phase.

Study Design: Longitudinal observational study. Measurements were undertaken between weeks 4-6 post-spinal cord injury (SCI), repeated at week 8 and every 4 weeks thereafter until week 20 or rehabilitation discharge, whichever occurred first., Objectives: Observe variation in measured resting energy expenditure (REE) and body composition in males undergoing SCI rehabilitation, compare REE with SCI-specific prediction equations incorporating fat-free mass (FFM), and explore the prevalence of clinical factors that may influence individual REE., Setting: Spinal Injuries Unit, Brisbane, Queensland, Australia., Methods: Indirect calorimetry was used to measure REE and bioimpedance spectroscopy to assess body composition. Four SCI-specific FFM-based REE and basal metabolic rate (BMR) prediction equations were compared to measured REE. A clinically significant change in REE was defined as +/- 10% difference from the week 4-6 measurement. Clinical factors that may affect REE variations were collected including infection, pressure injuries, autonomic dysreflexia, spasticity, and medications., Results: Fifteen people participated (mean age 35 ± 13 years, 67% paraplegic). There was no statistically significant change in mean REE, weight, or body composition, and the Chun and Nightingale BMR prediction equations performed best (r c  > 0.8 at all time points). One-third of participants had >10% change in REE on 11 occasions, with clinical factors not consistently associated with the observed changes., Conclusion: During SCI rehabilitation, mean REE, weight, and body composition remain unchanged, and FFM-based BMR prediction equations may be an acceptable alternative to indirect calorimetry. Future research designs should avoid single indirect calorimetry measures as snapshot data may not represent typical REE in this population., (© 2024. Crown.)

Introduction: Metabolic flexibility (MetF), defined as the ability to switch between fat and glucose oxidation, is increasingly recognised as a critical marker for assessing responses to dietary interventions. Previously, we showed that the consumption of multifibre bread improved insulin sensitivity and reduced low-density lipoprotein cholesterol (LDLc) levels in overweight and obese individuals. As a secondary objective, we aimed to explore whether our intervention could also improve MetF., Methods: In this study, 39 subjects at cardiometabolic risk participated in a double-blind, randomised, crossover trial lasting 8 weeks, repeated twice. During each phase, participants consumed either 150 g of standard bread daily or bread enriched with a mixture of seven dietary fibres. MetF response was assessed using a mixed-meal tolerance test (MMTT), analysing changes in respiratory quotient (∆RQ) measured using indirect calorimetry., Results: Although there were no significant differences in ∆RQ changes induced by dietary fibre between the two diets, these changes were positively correlated with postprandial triglyceride excursion (∆TG) at baseline. Subgroup analysis of baseline fasting and postprandial plasma metabolites was conducted to characterise MetF responders. These responders exhibited higher baseline fasting LDLc levels and greater post-MMTT ∆TG., Conclusion: In conclusion, although dietary fibres did not directly impact MetF in this study, our findings highlight potential determinants of MetF response, warranting further investigation in dedicated future interventions., (Journal of Human Nutrition and Dietetics© 2024 The Author(s). Journal of Human Nutrition and Dietetics published by John Wiley & Sons Ltd on behalf of British Dietetic Association.)

Evidence is growing that the individual adjustment of energy targets guided by indirect calorimetry (IC) can improve outcome. With the development of a new generation of devices that are easier to use and rapid, it appears important to share knowledge and expertise that may be used to individualize nutrition care. Despite the focus of this tutorial being on one contemporary device, the principles of IC apply across existing devices and can assist tailoring the nutrition prescription and in assessing response to nutrition therapy. The present tutorial addresses its clinical application in intubated mechanically ventilated and spontaneously breathing adult patients (canopy), i.e. it covers the range from critical illness to outpatients. The cases that are presented show how the measured energy expenditure (mEE), and the respiratory quotient (RQ), i.e. the ratio of expired CO 2 to consumed O 2 , should be applied in different cases, to adapt and individualize nutrition prescription, as it is a good marker of over- or underfeeding at the different stages of disease. The RQ also informs about the patient's body's capacity to use different substrates: the variations of RQ indicating the metabolic changes revealing insufficient or excessive feeding. The different cases reflect the use of a new generation device as a metabolic monitor that should be combined with other clinical observations and laboratory biomarkers. The tutorial also points to some shortcomings of the method, proposing alternatives., Competing Interests: Declaration of competing interest None of the authors declares any conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Introduction: Suboptimal nutrition promotes unfavorable outcomes in trauma patients, particularly among those aged 60 and over. While many institutions employ predictive energy equations to determine patients' energy requirements, mounting evidence shows these equations inaccurately estimate caloric needs. In this pilot randomized controlled trial, we sought to quantify the discrepancy between predictive equations and indirect calorimetry (IC)-the gold standard for determining energy requirements-in the older adult trauma population., Methods: This is a nested cohort study within a pilot randomized control trial in which 32 older adult trauma patients were randomized 3:1 to receive IC-guided nutrition delivery versus standard of care. IC requirements of patients in the intervention arm were compared to Mifflin St. Jeor (MSJ), Harris-Benedict (HB), and the American Society for Parenteral and Enteral Nutrition-Society of Critical Care Medicine (ASPEN-SCCM) predictive energy equations., Results: Twenty patients underwent IC to assess measured resting energy expenditure (mREE), yielding a mean (standard deviation) mREE of 23.1 ± 4.8 kcal/kg/d. MSJ and HB gave mean predictive resting energy expenditures of 17.5 ± 2.0 and 18.5 ± 2.0 kcal/kg/d in these patients, demonstrating that IC-derived values were 32.1% and 25.0% higher, respectively. When patients were stratified by body mass index (BMI), MSJ, and HB more severely underestimated caloric requirements in individuals with BMI <30 versus BMI 30-50. While the mean mREE fell within the mean predictive resting energy expenditure range prescribed by ASPEN-SCCM equations (21.4 ± 4.1 to 26.2 ± 4.3 kcal/kg/d), individuals' IC-derived values fell within their personal range in 8 of 20 cases., Conclusions: The MSJ and HB predictive energy equations consistently and significantly underpredict metabolic demands of older adult trauma patients compared to IC and perform worse in lower BMI individuals. ASPEN-SCCM equations frequently overpredict or underpredict resting energy expenditure. While these findings should be confirmed in a larger randomized control trial, this study suggests that institutions should prioritize IC to accurately identify the metabolic demands of older trauma patients., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The purpose of this study was to quantify the total energy expenditure (TEE) of international female rugby union players. Fifteen players were assessed over 14 days throughout an international multi-game tournament, which represented two consecutive one-match microcycles. Resting metabolic rate (RMR) and TEE were assessed by indirect calorimetry and doubly labelled water, respectively. Physical activity level (PAL) was estimated (TEE:RMR). Mean RMR, TEE, and PAL were 6.60 ± 0.93 MJ·day -1 (1578 ± 223 kcal·day -1 ), 13.51 ± 2.28 MJ·day -1 (3229 ± 545 kcal·day -1 ), and 2.0 ± 0.3 AU, respectively. There was no difference in TEE (13.74 ± 2.31 (3284 ± 554 kcal·day -1 ) vs. 13.92 ± 2.10 MJ·day -1 (3327 ± 502 kcal·day -1 ); p  = 0.754), or PAL (2.06 ± 0.26 AU vs. 2.09 ± 0.23 AU; p  = 0.735) across microcycles, despite substantial decreases in training load (total distance: -8088 m, collisions: -20 n, training duration: -252 min). After correcting for body composition, there was no difference in TEE (13.80 ± 1.74 (3298 ± 416 adj. kcal·day -1) vs. 13.16 ± 1.97 (3145 ± 471 adj. kcal·day -1 ) adj. MJ·day -1 , p  = 0.190), RMR (6.49 ± 0.81 (1551 ± 194 adj. kcal·day -1 ) vs. 6.73 ± 0.83 (1609 ± 198 adj. kcal·day -1 ) adj. MJ·day -1 , p  = 0.633) or PAL (2.15 ± 0.14 vs. 1.87 ± 0.26 AU, p  = 0.090) between forwards and backs. For an injured participant ( n  = 1), TEE reduced by 1.7 MJ·day -1 (-401 kcal·day -1 ) from pre-injury. For participants with illness ( n  = 3), TEE was similar to pre-illness (+0.49 MJ·day -1 (+117 kcal·day -1 )). The energy requirements of international female rugby players were consistent across one-match microcycles. Forwards and backs had similar adjusted energy requirements. These findings are critical to inform the dietary guidance provided to female rugby players., Competing Interests: LW is responsible for nutrition service delivery to the National Women’s Team at the Scottish Rugby Union (SRU). AB is head of athletic development at the SRU. CR and FM provide sports science support to the SRU.

Background: Acute kidney injury patients on continuous renal replacement therapy are subjected to alterations in metabolism, which in turn are associated with worse clinical outcome and mortality. The aim of this study is to determine which metabolism indicators can be used as independent predictors of 30 days intensive care unit (ICU) mortality., Methods: This was a prospective observational study on critical care patients on renal replacement therapy. Integrated approach of metabolism evaluation was used, combining the energy expenditure measured by indirect calorimetry, bioelectrical impedance provided fat free mass index (FFMI), amino acid and glucose concentrations. ICU mortality was defined as all cause 30 days mortality. Regression analysis was conducted to determine the conventional and metabolism associated predictors of mortality., Results: The study was conducted between the 2021 March and 2022 October. 60 high mortality risk patients (APACHE II of 22.98 ± 7.87, 97% on vasopressors, 100% on mechanical ventilation) were included during the period of the study. The rate of 30 days ICU mortality was 50% (n = 30). Differences across survivors and non-survivors in metabolic predictors were noted in energy expenditure (kcal/kg/day) (19.79 ± 5.55 vs 10.04 ± 3.97 p = 0.013), amino acid concentrations (mmol/L) (2.40 ± 1.06 vs 1.87 ± 0.90 p = 0.040) and glucose concentrations (mmol/L) (7.89 ± 1.90 vs 10.04 ± 3.97 p = 0.010). No differences were noted in FFMI (23.38 ± 4.25 vs 21.95 ± 3.08 p = 0.158). In the final linear regression analysis model, lower energy expenditure (exp(B) = 0.852 CI95%: 0.741-0.979 p = 0.024) and higher glucose (exp(B) = 1.360 CI95%: 1.013-1.824 p = 0.041) remained as independent predictors of the higher mortality., Conclusion: The results of the study imply strong association between the metabolic alterations and ICU outcome. Our findings suggest that lower systemic amino acid concentration, lower energy expenditure and higher systemic glucose concentration are predictive of 30 days ICU mortality., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Our study aims to define resting energy expenditure (REE) and describe the main nutritional patterns in a single-center cohort of children with Smith-Magenis syndrome (SMS). REE was calculated using indirect calorimetry. Patients' metabolic status was assessed by comparing measured REE (mREE) with predictive REE (pREE). Patients also underwent multidisciplinary evaluation, anthropometric measurements and an assessment of average energy intake, using a 3-day food diary, which was reviewed by a specialized dietitian. Twenty-four patients (13 M) were included, the median age was 9 years (IC 95%, 6-14 years), 84% had 17p11.2 deletion, and 16% had RAI1 variants. REE was not reduced in SMS pediatric patients, and the mREE did not differ from the pREE. In patients with RAI1 variants (16%, n = 3/24), obesity was more prevalent than those with 17p11.2 deletion (100% vs 38%). Lower proteins intake and higher total energy intake were reported in obese and overweight patients, compared to healthy weight children. No significant difference was found between males and females in energy or macronutrient intake., Conclusions: In SMS, the onset of obesity is not explained by REE abnormalities, but dietary factors seem to be crucial. Greater concern should be addressed to patients with RAI1 variants. A better understanding of the molecular mechanisms causing obesity in SMS patients could set the basis for possible future targeted therapies., What Is Known: • More than 90% of SMS patients after the age of 10 are overweight or obese., What Is New: • Onset of overweight and obesity in SMS pediatric patients is not explained by abnormal resting energy expenditure. • The development of syndrome-specific dietary guidelines for SMS patients should be of utmost relevance and are highly needed., (© 2024. The Author(s).)

Although climate change is predicted to have a substantial effect on the energetic requirements of organisms, the longer-term implications are often unclear. Sloths are limited by the rate at which they can acquire energy and are unable to regulate core body temperature (T b ) to the extent seen in most mammals. Therefore, the metabolic impacts of climate change on sloths are expected to be profound. Here we use indirect calorimetry to measure the oxygen consumption (VO 2 ) and T b of highland and lowland two-fingered sloths ( Choloepus hoffmanni) when exposed to a range of different ambient temperatures (T a ) (18 °C -34 °C), and additionally record changes in T b and posture over several days in response to natural fluctuations in T a . We use the resultant data to predict the impact of future climate change on the metabolic rate and T b of the different sloth populations. The metabolic responses of sloths originating from the two sites differed at high T a 's, with lowland sloths invoking metabolic depression as temperatures rose above their apparent 'thermally-active zone' (TAZ), whereas highland sloths showed increased RMR. Based on climate change estimates for the year 2100, we predict that high-altitude sloths are likely to experience a substantial increase in metabolic rate which, due to their intrinsic energy processing limitations and restricted geographical plasticity, may make their survival untenable in a warming climate., Competing Interests: The authors declare there are no competing interests. The authors are not aware of any competing interests that the Indiegogo crowdfunders and Sloth Conservation Foundation donors may have., (©2024 Cliffe et al.)

Our study aimed to validate existing equations and develop the new NRG CO equation to estimate resting energy expenditure (REE) in the Colombian population with moderate-to-high physical activity levels. Upon satisfying the inclusion criteria, a total of 86 (43F, 43M) healthy adults (mean [SD]: 27.5 [7.7] years; 67.0 [13.8] kg) were evaluated for anthropometric variables and REE by indirect calorimetry using wearable gas analyzers (COSMED K4 and K5). Significant positive correlations with REE were found for body mass ( r = 0.65), body mass-to-waist ( r = 0.58), arm flexed and tensed girth ( r = 0.66), corrected thigh girth ( r = 0.56), corrected calf girth ( r = 0.61), and sum of breadths (∑3D, r = 0.59). As a novelty, this is the first time a significant correlation between REE and the sum of corrected girths (∑3CG, r = 0.63) is reported. Although existing equations such as Harris-Benedict ( r = 0.63), Mifflin-St. Jeor ( r = 0.67), and WHO ( r = 0.64) showed moderate-to-high correlations with REE, the Bland-Altman analysis revealed significant bias ( p < 0.05), indicating that these equations may not be valid for the Colombian population. Thus, participants were randomly distributed into either the equation development group (EDG, n = 71) or the validation group (VG, n = 15). A new model was created using body mass, sum of skinfolds (∑8S), corrected thigh, corrected calf, and age as predictors ( r = 0.755, R 2 = 0.570, RMSE = 268.41 kcal). The new NRG CO equation to estimate REE (kcal) is: 386.256 + (24.309 × BM) - (2.402 × ∑8S) - (21.346 × Corrected Thigh) + (38.629 × Corrected Calf) - (7.417 × Age). Additionally, a simpler model was identified through Bayesian analysis, including only body mass and ∑8S ( r = 0.724, R 2 = 0.525, RMSE = 282.16 kcal). Although external validation is needed, our validation resulted in a moderate correlation and concordance (bias = 91.5 kcal) between measured and estimated REE values using the new NRG CO equation., Competing Interests: D.A.B. and K.F.-H. are certified Level Three Anthropometrists (Instructors) by the International Society for the Advancement of Kinanthropometry (ISAK). D.A.B. has conducted academic-sponsored research on anthropometry and has received honoraria for selling anthropometric equipment and speaking about anthropometry at international conferences/private courses. Also, he is an active member of the Red Iberoamericana de Investigadores en Antropometr&iacute;a Aplicada&mdash;RIBA2. R.B.K. has conducted industry-sponsored studies at the universities he has been affiliated with and occasionally serves as a scientific and legal consultant related to exercise and nutrition intervention studies. The other authors declare no conflicts of interest. All authors are responsible for the content of this article.

Introduction: The effect of eccentric exercise-induced muscle damage (EIMD) on cycling efficiency is unknown. The aim of the present study was to assess the effect of EIMD on gross and delta efficiency and the cardiopulmonary responses to cycle ergometry., Methods: Twenty-one recreational athletes performed cycling at 70%, 90%, and 110% of the gas exchange threshold (GET) under control conditions (Control) and 24 h following an eccentric damaging protocol (Damage). Knee extensor isometric maximal voluntary contraction, potentiated twitch ( Qtw,pot ), and voluntary activation were assessed before Control and Damage. Gross and delta efficiency were assessed using indirect calorimetry, and cardiopulmonary responses were measured at each power output. Electromyography root-mean-square (EMG RMS ) during cycling was also determined., Results: Maximal voluntary contraction was 25% ± 18% lower for Damage than Control ( P < 0.001). Gross efficiency was lower for Damage than Control ( P < 0.001) by 0.55% ± 0.79%, 0.59% ± 0.73%, and 0.60% ± 0.87% for 70%, 90%, and 110% GET, respectively. Delta efficiency was unchanged between conditions ( P = 0.513). Concurrently, cycling EMG RMS was higher for Damage than Control ( P = 0.004). An intensity-dependent increase in breath frequency and V̇ E /V̇CO 2 was found, which were higher for Damage only at 110% GET ( P ≤ 0.019)., Conclusions: Thus, gross efficiency is reduced following EIMD. The concurrently higher EMG RMS suggests that increases in muscle activation in the presence of EIMD might have contributed to reduced gross efficiency. The lack of change in delta efficiency might relate to its poor reliability hindering the ability to detect change. The findings also show that EIMD-associated hyperventilation is dependent on exercise intensity, which might relate to increases in central command with EIMD., (Copyright © 2024 by the American College of Sports Medicine.)

Background & Aims: In recent times, the complexity of food styles and meal content has increased, leading to significant variations in macronutrient composition between meals. This phenomenon has coincided with a rise in obesity rates. We aimed to determine whether a large variation in macronutrient composition between meals results in reduced fat oxidation., Methods: A cross-over study was conducted with 13 healthy young men, using whole-body indirect calorimetry to test 24-h energy metabolic responses under three conditions: regular meals (R), high-carbohydrate breakfast (CB), or high-fat breakfast (FB), each with different macronutrient contents. The R condition included three meals daily with the same macronutrient composition. The CB condition included a high-carbohydrate meal at breakfast, high-fat meal at lunch, and high-carbohydrate meal at dinner. The FB condition included a high-fat meal at breakfast, high-carbohydrate meal at lunch, and high-carbohydrate meal at dinner. The daily macronutrient compositions were similar across the three conditions, except that CB and FB had larger variations in carbohydrate-fat balance between meals than R. The participants were tested in random order. During the dietary intervention, we compared 24-h whole-body metabolic parameters, including substrate oxidation (e.g., 24 h respiratory quotient [RQ])., Results: No significant differences were observed in the measures of energy expenditure among the three conditions. However, after adjusting for the sleeping RQ on a preceding day, the estimated 24hRQ was lower under the FB condition (0.845) than under the R (0.854, P = 0.0077 vs. FB) and CB conditions (0.853, P = 0.016 vs. FB). No difference was observed in the magnitude of the 5-h RQ change from lunch to dinner under the CB condition and in the magnitude of change from breakfast to lunch under the FB condition., Conclusions: A large variation in the carbohydrate-fat balance between meals does not decrease daily fat oxidation. An FB may increase daily fat oxidation compared to a CB when the daily food quotient is constant, but this increase may not be owing to the upregulation of fat burning on a daily basis., Competing Interests: Conflict of interest None of the authors has a direct conflict of interest to declare., (Copyright © 2024 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Purpose : In this study we evaluated the reliability of blood lactate levels (BLa), energy expenditure and substrate utilization during prolonged exercise at the intensity that elicits maximal fat oxidation (FATmax). Furthermore, we investigated the accuracy of a single graded exercise test (GXT) for predicting energy metabolism at FATmax. Methods : Seventeen young men with obesity (26 ± 6 years; 36.4 ± 7.2 %body fat) performed a GXT on a treadmill in a fasted state (10-12 h) for the assessment of FATmax and cardiorespiratory fitness. Afterward, each subject performed two additional prolonged FATmax trials (102 ± 11 beats·min -1 ; 60-min) separated by 7 days. Indirect calorimetry was used for the assessment of energy expenditure and substrate utilization kinetics whereas capillary blood samples were taken for the measurement of BLa. Results : The BLa (limits of agreement (LoA): -1.2 to 0.8 mmol∙L -1 ; p = 1.0), fat utilization (LoA: -8.0 to 13.4 g∙h -1 ; p = 0.06), and carbohydrate utilization (LoA: -27.6 to 22.4 g∙h -1 ; p = 0.41) showed a good agreement whereas a modest systematic bias was found for energy expenditure (LoA: -16811 to 33355 kJ∙h -1 ; p < 0.05). All the aforementioned parameters showed a moderate to good reliability (Intraclass correlation coefficient: 0.67-0.92). The GXT overestimated fat (~46%) and carbohydrate (~26%) utilization as well as energy expenditure (36%) during steady-state exercise at FATmax. Conversely the GXT underestimated BLa (~28%). Conclusion : a single GXT cannot be used for an accurate prediction of energy metabolism during prolonged exercise in men with obesity. Thus, an additional steady-state FATmax trial (40-60 min) should be performed for a tailored and precise exercise prescription.

This study investigated the effect of 4 days low energy availability (LEA) on physiological markers and mood states in male endurance runners. Twelve participants (mean (standard deviation); age: 25.8 (3.8) years; fat-free mass (FFM): 52.8 (5.5) kg) completed three 4-day conditions: adequate energy availability (AEA): 45 kcal/kg FFM/day; LEA1: 30 kcal/kg FFM/day; and LEA2: 15 kcal/kg FFM/day, in a randomized order. Participants ran on a treadmill at 65% of V̇O 2 max until they expended 15 kcal/kg FFM/day of energy. Energy intake was adjusted to achieve the desired energy availability. Pre- and post-measurements of bone turnover, metabolism, testosterone and estradiol (plasma), resting metabolic rate (indirect calorimetry), and mood states (Brunel Mood Scale) were assessed. The results reported a significant decrease in testosterone (condition × time interaction, p  = 0.03) occurred on LEA2 (Pre: 23.8 (7.0) nmol/L vs. Post: 20.3 (7.7) nmol/L) compared with AEA (Pre: 22.9 (5.5) nmol/L vs. Post: 23.3 (6.1) nmol/L) or LEA1 (Pre: 23.6 (8.6) nmol/L vs. Post: 20.9 (8.8) nmol/L). Fatigue level significantly increased (condition × time interaction, p  = 0.02) in LEA2 (Pre: 3.5 (1.7) vs. Post: 6.5 (2.9)) but did not change in AEA (Pre: 2.8 (1.5) vs. Post: 2.5 (2.7)) or LEA1 (Pre: 2.8(2.4) vs. Post: 2.9 (2.0)). Other measures were unaffected by the interventions. In conclusion, this study suggests that testosterone and fatigue may serve as early indicators of LEA in male runners. However, other physiological markers and mood states appeared largely unaffected, aligning with existing literature indicating minimal disruption of physiological functions during acute LEA in male athletes. Study registration: Australian New Zealand Clinical Trials Registry (Trial No.: 381278)., Competing Interests: The authors declare there are no competing interests.

Purpose of Review: Accurate assessment of dietary intake, especially energy and protein intake, is crucial for optimizing nutritional care and outcomes in patients with cancer. Validation of dietary assessment methods is necessary to ensure accuracy, but the validity of these methods in patients with cancer, and especially in those with cancer cachexia, is uncertain. Validating nutritional intake is complex because of the variety of dietary methods, lack of a gold standard method, and diverse validation measures. Here, we review the literature on validations of dietary intake methods in patients with cancer, including those with cachexia, and highlight the gap between current validation efforts and the need for accurate dietary assessment methods in this population., Recent Findings: We analyzed eight studies involving 1479 patients with cancer to evaluate the accuracy and reliability of 24-hour recalls, food records, and food frequency questionnaires in estimating energy and protein intake. We discuss validation methods, including comparison with biomarkers, indirect calorimetry, and relative validation of dietary intake methods., Summary: Few have validated dietary intake methods against objective markers in patients with cancer. While food records and 24-hour recalls show potential accuracy for energy and protein intake, this may be compromised in hypermetabolic patients. Additionally, under- and overreporting of intake may be less frequent, and the reliability of urinary nitrogen as a protein intake marker in patients with cachexia needs further investigation. Accurate dietary assessment is important for enhancing nutritional care outcomes in cachexia trials, requiring validation at multiple time points throughout the cancer trajectory., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Nutrition guidance for athletes must consider a range of variables to effectively support individuals in meeting energy and nutrient needs. Resistance exercise is a widely adopted training method in athlete preparation and rehabilitation and therefore is one such variable that will influence nutrition guidance. Given its prominence, the capacity to meaningfully quantify resistance exercise energy expenditure will assist practitioners and researchers in providing nutrition guidance. However, the significant contribution of anaerobic metabolism makes quantifying energy expenditure of resistance exercise challenging., Objective: The aim of this scoping review was to investigate the methods used to assess resistance exercise energy expenditure., Methods: A literature search of Medline, SPORTDiscus, CINAHL and Web of Science identified studies that included an assessment of resistance exercise energy expenditure. Quality appraisal of included studies was performed using the Rosendal Scale., Results: A total of 19,867 studies were identified, with 166 included after screening. Methods to assess energy expenditure included indirect calorimetry (n = 136), blood lactate analysis (n = 25), wearable monitors (n = 31) and metabolic equivalents (n = 4). Post-exercise energy expenditure was measured in 76 studies. The reported energy expenditure values varied widely between studies., Conclusions: Indirect calorimetry is widely used to estimate energy expenditure. However, given its limitations in quantifying glycolytic contribution, indirect calorimetry during and immediately following exercise combined with measures of blood lactate are likely required to better quantify total energy expenditure. Due to the cumbersome equipment and technical expertise required, though, along with the physical restrictions the equipment places on participants performing particular resistance exercises, indirect calorimetry is likely impractical for use outside of the laboratory setting, where metabolic equivalents may be a more appropriate method., (© 2024. The Author(s).)

Abstract Aims: To evaluate the nutritional status, resting energy expenditure, caloric and protein intake, and evolution of biochemical parameters in three stages of chronic kidney disease: pre-dialytic, at the beginning of the dialysis treatment, and 30 days after starting treatment. Methods: The chi-square and Student’s t tests were used to compare the variables, and analysis of repeated measurements was used to compare the data obtained in the three moments evaluated. The results were discussed at the 5% level of significance. Results: We evaluated 35 patients, 60% female and 60% with diabetes mellitus. There was a decrease in midarm circumference and serum albumin. Inflammatory state and caloric and protein intake increased. There was no significant difference in resting energy expenditure in the three moments. The serum urea and serum albumin, handgrip strength, and protein consumption after 30 days from the start of dialysis were greater in the peritoneal dialysis patients, when compared to the hemodialysis population. Conclusion: there was a decrease in midarm circumference and serum albumin and an increase in protein intake after dialysis. The peritoneal dialysis patients had higher muscle strength, even with lower protein intake. Resting energy expenditure was not different between dialysis methods and the moments evaluated.

Objectives: To compare different types of activity trackers recording physical activity energy expenditure (PAEE) and examine their criterion validity against indirect calorimetry (IC) as the gold standard in adults over 60 years of age with a special focus on women with cardiovascular risk., Design: Synchronous registrations of PAEE were performed with up to four different devices to determine criterion validity against IC while participants performed a protocol of simulated activities in a laboratory setting., Method: Thirty-four participants (25 women, 9 men) with at least a light cardiac risk performed a protocol of simulated activities in a laboratory setting (daily living activities, cycle ergometer test). PAEE was simultaneously assessed by IC, two research-grade activity trackers (ActiGraph-wGT3X-BT and Actiheart-4) and two consumer-level activity trackers (OMRON pedometer and Fitbit Charge-3). Tracker-derived PAEE was compared with PAEE calculated from IC descriptively and by Bland-Altman plots., Results: The ActiGraph (0.7 ± 0.4 kcal/min), the Actiheart (1.1 ± 0.6 kcal/min) and the OMRON (0.8 ± 0.6 kcal/min) underestimated, while the Fitbit (3.4 ± 1.2 kcal/min) overestimated PAEE compared to IC-PAEE (2.0 ± 0.5 kcal/min). The Bland-Altman limits of agreement (LoA) against IC were +0.5/+2.2 kcal/min for the ActiGraph, -0.3/+2.1 kcal/min for the Actiheart, -3.7/+1.0 kcal/min for the Fitbit, and -0.5/+2.9 kcal/min for the OMRON. The magnitude of the deviation varied considerably depending on the activity (e.g. walking, cleaning, cycle ergometer test)., Conclusions: The research-grade activity trackers estimated PAEE with higher validity than the commercially available activity trackers. The partly very wide LoA have to be critically considered when assessing PAEE in the context of health service research, as individual Physical Activity behaviour may be under- or overestimated., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Rieckmann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: It is essential to better characterize the energetic profile of individuals during very low-intensity physical activity. The objectives of the present study were to determine whether the saver profile from sit-to-stand persists during light physical activity and characterize patterns in substrate utilization from sit-to-stand and during very low-intensity physical activity in healthy men and women., Methods: Sixty-two healthy adults (38 women) performed an experimental sequence that corresponded to 15-minute sitting (SIT1), followed by 15-minute standing (STAND), 15-minute sitting again (SIT2), and finally 15 minutes of light cycling. Continuous indirect calorimetry was allowed to calculate energy expenditure (EE) and respiratory quotient through the entire sequence. Savers and nonsavers (<5% and ≥ 5% increase in EE from sitting to standing, respectively) were determined., Results: There was an interaction effect in EE between savers and nonsavers through the whole sequence (P = .008). Only nonsavers (71%) exhibited a significant increase in EE from SIT1 to STAND (P < .001). Nonsavers and savers significantly increased EE during 15 minutes of light cycling relative to sitting or standing (P < .001), without any difference between groups. The percentage of change in respiratory quotient from SIT1 to STAND was significantly different between the 2 groups, with increased values in savers and decreased values in nonsavers (P = .03). Significantly lower values in respiratory quotient and EE were found during 15 minutes of light cycling in women compared with men (P < .001)., Conclusions: It is essential to determine individuals' energetic phenotype to determine those who may benefit more from strategies such as standing or light physical activity. The sexual dimorphism in terms of substrate use during such exercise should be considered.

Background: Total energy expenditure (TEE) is the total energy expended by an individual to sustain life, activities, and growth. TEE is formed by four components: resting energy expenditure (REE), activity energy expenditure (AEE), growth-related energy expenditure (GEE), and the thermic effect of feeding (TEF). Some energy expenditure (EE) components may change throughout childhood and cannot be reliably estimated using prediction formulae., Objective: To summarize measured TEE components as reported in the literature in healthy and critically ill children., Methods: We searched MEDLINE, EMBASE, and CINAHL for studies published between 1946 and 7 September 2023. The primary outcome was energy expenditure. Included studies were published in English and measured one or more of TEE, AEE, GEE, and TEF with Indirect Calorimetry or Doubly Labeled Water in participants between 1 month and 18 years of age. We excluded studies reporting only REE or using predictive equations. Following abstraction, reported values were converted into kcal/kg/day or kcal/day as possible. Weighted mean values were calculated using median or means of EE measurements., Results: We found 138 studies, 8163 patients, and 16,636 eligible measurements. The median (IQR) study sample size was 20 (12, 35) patients. TEE was the most evaluated component. The median (IQR) TEE in infants was 73.1 (67.0, 76.5), in children 78.0 (66.0, 81.3), and in adolescents was 44.2 (41.8, 51.9) kcal/kg/day. Very few studies reported on GEE and TEF., Conclusions: This is one of the first studies that summarizes components of total energy expenditure in different pediatric age groups in healthy and critically ill children. Growth- and feeding-associated energy expenditure are poorly reported in healthy children, while all components of TEE (except REE) are poorly reported in critically ill children.

To establish the criterion-assessed energy and fluid requirements of female netball players, 13 adult players from a senior Netball Super League squad were assessed over 14 days in a cross-sectional design, representing a two- and one-match microcycle, respectively. Total energy expenditure (TEE) and water turnover (WT) were measured by doubly labeled water. Resting and activity energy expenditure were measured by indirect calorimetry and Actiheart, respectively. Mean 14-day TEE was 13.46 ± 1.20 MJ day -1 (95% CI, 12.63-14.39 MJ day -1 ). Resting energy expenditure was 6.53 ± 0.60 MJ day -1 (95% CI, 6.17-6.89 MJ day -1 ). Physical activity level was 2.07 ± 0.19 arbitrary units (AU) (95% CI, 1.95-2.18 AU). Mean WT was 4.1 ± 0.9 L day -1 (95% CI, 3.6-4.7 L day -1 ). Match days led to significantly greater TEE than training (+2.85 ± 0.70 MJ day -1 ; 95% CI, +1.00- +4.70 MJ day -1 ; p = 0.002) and rest (+4.85 ± 0.70 MJ day -1 ; 95% CI, +3.13-+6.56 MJ day -1 ; p < 0.001) days. Matches led to significantly greater energy expenditure (+1.85 ± 1.27 MJ; 95% CI, +0.95-+2.76 MJ day -1 ; p = 0.001) than court-based training sessions. There was no significant difference in TEE (+0.03 ± 0.35 MJ day -1 ; 95% CI, -0.74-+0.80 MJ day -1 ; p = 0.936) across weeks. Calibrated Actiheart 5 monitors underestimated TEE (-1.92 ± 1.21 MJ day -1 ). Energy and fluid turnover were greatest on match days, followed by training and rest days, with no difference across weeks. This study provides criterion-assessed energy and fluid requirements to inform dietary guidance for female netball players., (© 2024 The Author(s). European Journal of Sport Science published by Wiley‐VCH GmbH on behalf of European College of Sport Science.)

Humans require energy to sustain their daily activities throughout their lives. This narrative review aims to ( a ) summarize principles and methods for studying human energy expenditure, ( b ) discuss the main determinants of energy expenditure, and ( c ) discuss the changes in energy expenditure throughout the human life course. Total daily energy expenditure is mainly composed of resting energy expenditure, physical activity energy expenditure, and the thermic effect of food. Total daily energy expenditure and its components are estimated using variations of the indirect calorimetry method. The relative contributions of organs and tissues determine the energy expenditure under different physiological conditions. Evidence shows that energy expenditure varies along the human life course, at least in part due to changes in body composition, the mass and specific metabolic rates of organs and tissues, and levels of physical activity. This information is crucial to estimate human energy requirements for maintaining health throughout the life course.

Study Question: Is resting energy expenditure (REE) altered in women with polycystic ovary syndrome (PCOS)?, Summary Answer: Women with PCOS have a reduction in REE, when corrected for fat-free mass, independent of PCOS clinical phenotypes and BMI categories., What Is Known Already: Obesity is an important issue in women with PCOS, in terms of frequency and pathophysiological implications. It has been hypothesized that obesity may be favoured by alterations in REE, but the studies have been limited and conflicting., Study Design, Size, Duration: This case-control study was a comparison of 266 women with PCOS and 51 healthy controls, recruited in the Verona 3P study from 2010 to 2021., Participants/materials, Setting, Methods: Women with PCOS diagnosed by the Rotterdam criteria, with normal thyroid function and no interfering medications, were referred to the outpatient clinic of a tertiary care centre of endocrinology and metabolism for a measurement of REE. Healthy controls were recruited in the same period and submitted to the same procedure. In all subjects, REE was measured by indirect calorimetry and serum androgens were measured by LC-MS/MS. In women with PCOS, insulin sensitivity was assessed using the hyperinsulinemic-euglycemic clamp., Main Results and the Role of Chance: REE was similar in women with PCOS and controls. However, REE corrected for fat-free mass (REE/FFM) was significantly lower in women with PCOS than in controls (31.8 ± 4.0 vs 35.4 ± 3.9 kcal/kgFFM·day, P < 0.001). REE/FFM did not differ between normal-weight, overweight, or obese women with PCOS, and each of these subgroups showed lower REE/FFM values than controls. Reduced REE/FFM values were found in each phenotype of the syndrome. In multiple regression analysis, REE/FFM was independently associated with age and PCOS status, but not with fat mass. In PCOS women, REE/FFM was independently and directly associated with ovarian follicle number., Limitations, Reasons for Caution: Limitations of the study are the cross-sectional design, which limits the causal inference of the results, and the unavailability of precise information about lifestyle factors, which may be potential confounders. Further prospective studies are needed to establish the importance of this phenomenon in contributing to the weight excess of PCOS., Wider Implications of the Findings: A reduction of REE could potentially favour weight gain in women with PCOS and possibly contribute to the altered metabolic profile typical of this condition, even counteracting the therapeutic strategies aimed to reduce excess body fat in these women. Nevertheless, the presence of this abnormality in both obese/overweight and normal-weight patients suggests that other factors must play a role in this phenomenon., Study Funding/competing Interest(s): This work was supported by academic grants to PM from the University of Verona (FUR 2010-2022). All authors declare no conflict of interest., Trial Registration Number: N/A., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: This study investigated whether exposure to suboptimal gestational factors (SGFs) alters mechanical efficiency (ME) and substrate oxidation during rest and exercise in children as a mechanism contributing to obesity., Methods: Data from the Quebec Adiposity and Lifestyle Investigation in Youth cohort were used. Children aged 8 to 10 years performed an incremental maximal cycling test with indirect calorimetry. Their ME was measured during submaximal and maximal effort. The substrate oxidation during rest and submaximal effort was also computed. ME and substrate oxidation results between children exposed to each SGF during pregnancy (gestational diabetes mellitus: n = 68; hypertensive disorders: n = 49; maternal smoking: n = 77) and nonexposed children (n = 370) were compared., Results: No difference was observed for ME during submaximal (F [3,540]  = 0.46, p = 0.713) and maximal effort (F [3,545]  = 0.86, p = 0.463) between exposed and nonexposed children. The percentage contributions of lipids and carbohydrates did not differ during rest (F [3,545] =1.68, p = 0.169) or submaximal exercise (F [3,544]  = 0.31, p = 0.534) between exposed and nonexposed children., Conclusions: Children exposed to investigated SGFs display a similar physiological response regarding ME and substrate oxidation during rest and exercise compared to nonexposed children. Future studies should confirm these novel results and continue investigating other research avenues to explain the higher risk of obesity in this population., (© 2024 The Obesity Society.)

Background/objectives: Type 1 diabetes (T1D) is associated with an increase in resting metabolic rate (RMR), but the impact of T1D on other components of 24-h energy expenditure (24-h EE) is not known. Also, there is a lack of equations to estimate 24-h EE in patients with T1D. The aims of this analysis were to compare 24-h EE and its components in young adults with T1D and healthy controls across the spectrum of body mass index (BMI) and derive T1D-specific equations from clinical variables., Subjects/methods: Thirty-three young adults with T1D diagnosed ≥1 year prior and 33 healthy controls matched for sex, age and BMI were included in this analysis. We measured 24-h EE inside a whole room indirect calorimeter (WRIC) and body composition with dual x-ray absorptiometry., Results: Participants with T1D had significantly higher 24-h EE than healthy controls (T1D = 2047 ± 23 kcal/day vs control= 1908 ± 23 kcal/day; P < 0.01). We derived equations to estimate 24-h EE with both body composition (fat free mass + fat mass) and anthropometric (weight + height) models, which provided high coefficients of determination (R 2  = 0.912 for both). A clinical model that did not incorporate spontaneous physical activity yielded high coefficients of determination as well (R 2  = 0.897 and R 2  = 0.880 for body composition and anthropometric models, respectively)., Conclusion: These results confirm that young adults with established T1D have increased 24-h EE relative to controls without T1D. The derived equations from clinically available variables can assist clinicians with energy prescriptions for weight management in patients with T1D., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background and Objectives: A sustained mismatch between energy intake (EI) and exercise energy expenditure (EEE) can lead to Low Energy Availability (LEA), as well as health and performance impairments characteristic of Relative Energy Deficiency in Sport (RED-S). Research in females has identified specific LEA cut-points for the risks of developing physiological and performance disturbances. Cut-points in males have yet to be evaluated; therefore, this study examined the prevalence of LEA in highly trained male cross-country skiers. The key purpose of this study was to analyze EI, resting energy expenditure (REE), EEE, and energy availability (EA) in highly trained cross-country skiers during the preparation and competition periods. The secondary objective of our study was to evaluate the relative contribution of fats and carbohydrates to EI, REE, and EEE., Materials and Methods: EI was determined by an estimated 24 h diet recall method, REE was assessed by indirect calorimetry, and EEE was estimated from heart rate in 27 cross-country skiers., Results: EI amounted to 4050 ± 797 kcal/day on a typical training day (TD) and 5986 ± 924 kcal/day ( p < 0.001) on a typical competition day (CD). REE on TDs (2111 ± 294 kcal/day or 30 ± 6 kcal/day/kg) was higher ( p < 0.05) than on CDs (1891 ± 504 kcal/day or 27 ± 7 kcal/day/kg). The EA in the athletes was <15 kcal∙kg FFM -1 ·d -1 on TDs and <65 kcal∙kg FFM -1 ·d -1 on CDs. EI was not optimal, as indicated by low EA throughout TDs (June). This could be associated with insufficient EI along with a high amount of EEE (3690.7 ± 485.2 kcal/day). During the transition from TD to CD, an increase in the contribution of fats to EI and EEE was observed in cross-country skiers., Conclusion: The conception of LEA and REDs and their potential implication for performance is underestimated among coaches and athletes. The importance of appropriate dietary strategies is essential to ensure that enough calories are consumed to support efficient training.

This study aimed to investigate the resting metabolic rate (RMR) in cross-training practitioners (advanced and novice) using indirect calorimetry (IC) and compare it with predictive equations proposed in the scientific literature., Methods: A cross-sectional and comparative study analyzed 65 volunteers, both sexes, practicing cross-training (CT). Anthropometry and body composition were assessed, and RMR was measured by IC (FitMate PRO ® ), bioimpedance (BIA-InBody 570 ® ), and six predictive equations. Data normality was tested by the Kolgomorov-Smirnov test and expressed as mean ± standard deviation with 95% confidence intervals (CI), chi-square test was performed to verify ergogenic resources, and a Bland-Altman plot (B&A) was made to quantify the agreement between two quantitative measurements. One-way ANOVA was applied to body composition parameters, two-way ANOVA with Bonferroni post hoc was used to compare the RMR between groups, and two-way ANCOVA was used to analyze the adjusted RMR for body and skeletal muscle mass. The effect size was determined using Cohen's d considering the values adjusted by ANCOVA. If a statistical difference was found, post hoc Bonferroni was applied. The significance level was p < 0.05 for all tests., Results: The main results indicated that men showed a higher RMR than women, and the most discrepant equations were Cunningham, Tinsley (b), and Johnstone compared to IC. Tinsley's (a) equation indicated greater precision in measuring the RMR in CM overestimated it by only 1.9%, and BIA and the Harris-Benedict in CW overestimated RMR by only 0.1% and 3.4%, respectively., Conclusions: The BIA and Harris-Benedict equation could be used reliably to measure the RMR of females, while Tinsley (a) is the most reliable method to measure the RMR of males when measuring with IC is unavailable. By knowing which RMR equations are closest to the gold standard, these professionals can prescribe a more assertive diet, training, or ergogenic resources. An assertive prescription increases performance and can reduce possible deleterious effects, maximizing physical sports performance.

Prader-Willi syndrome (PWS) is a rare disorder characterised by varying nutritional phases that occur throughout the lifespan, ranging from failure to thrive to hyperphagia. If uncontrolled, the imbalance between energy intake and expenditure results in obesity development and increased morbidity and mortality risk. Although measures of energy requirements for accurate nutrition assessment are vital, the evidence appears sparse and heterogeneous; hence, the aim of this review was to examine the available literature on energy expenditure predicted or measured using various methods in individuals with PWS. Studies were sought that presented methods and results on resting energy expenditure or basal metabolic rate. A narrative synthesis was completed to present the study characteristics and results. Methods of determining energy requirements included predictive equations and indirect calorimetry. Differences amongst ages, growth hormone therapy, fasting status, and measures in which results were presented were limitations to appropriately summarising and identifying trends in energy expenditure. Indirect calorimetry was identified as the most accurate method; however, it is not widely available in all settings. Further research is encouraged to support the development of valid and reliable predictive equations that will better inform and improve the efficiency of clinical practice in supporting people with PWS.

The progression of Duchenne muscular dystrophy (DMD)requires the assessment of nutritional disturbances at each stage of the disease. The purpose of this study was to assess the nutritional status in various ages of boys with DMD using screening and in-depth evaluation methods. Body composition by Dual X-ray Absorptiometry (DXA), basal metabolic rate (BMR) by indirect calorimetry, a questionnaire of nutritional status-Pediatric Nutrition Screening Tool (PNST)-and laboratory parameters were performed. In the cohort of 93 boys aged 8.54 (5.9-12.6 years), inappropriate nutritional status occurred in 41.8% of boys (underweight 11.8%, overweight 16.0%, and obesity 14.0%). In the 10-13 age group, the occurrence of overweight and underweight was the highest. Based on PNST, 15.1% of patients were at nutritional risk (≥2 points)-the most in the 14-17 age group (29%). A negative correlation was identified between PNST and z-scores of body weight, BMI, and FFMI (r Spearman = -0.49, -0.46, and -0.48, respectively; p < 0.05). There were no differences between BMR results from indirect calorimetry and calculations from the Schofield formula for any age group. In obese boys, the caloric requirement in indirect calorimetry was significantly lower than that indicated by the calculations according to the Schofield formula ( p < 0.028). Inappropriate nutritional status occurred in almost half of the children with DMD. The age group in which nutritional disorders were most frequently identified was 10-13 years old. PNST could be considered a tool for screening malnutrition after testing a larger group of DMD patients.

Background and Objectives: Resting energy expenditure (REE) assessments can help inform clinical treatment decisions in adolescents with elevated body mass index (BMI), but current equations are suboptimal for severe obesity. We developed a predictive REE equation for youth with severe obesity and obesity-related comorbidities and compared results to previously published predictive equations., Methods: Data from indirect calorimetry, clinical measures, and body composition per Dual x-ray absorptiometry (DXA) were collected from five sites. Data were randomly divided into development (N = 438) and validation (N = 118) cohorts. A predictive equation was developed using Elastic Net regression, using sex, race, ethnicity, weight, height, BMI percent of the 95th%ile (BMIp95), waist circumference, hip circumference, waist/hip ratio, age, Tanner stage, fat and fat-free mass. This equation was verified in the validation cohort and compared with 11 prior equations., Results: Data from the total cohort (n = 556, age 15 ± 1.7 years, 77% female, BMIp95 3.3 ± 0.94) were utilized. The best fit equation was REE = -2048 + 18.17 × (Height in cm) - 2.57 × (Weight in kg) + 7.88 × (BMIp95) + 189 × (1 = male, 0 = female), R 2  = 0.466, and mean bias of 23 kcal/day., Conclusion: This new equation provides an updated REE prediction that accounts for severe obesity and metabolic complications frequently observed in contemporary youth., (© 2024 World Obesity Federation.)

The increasing preference for indoor exercise spaces highlights the relationship between indoor thermal environments and physiological responses, particularly concerning thermal comfort during physical activity. Determining the metabolic heat production rate during exercise is essential for optimizing the thermal comfort, well-being, and performance of individuals engaged in physical activities. This value can be determined during the activity using several methods, including direct calorimetry measurement, indirect calorimetry that uses analysis of respiratory gases, or approximations using collected data such as speed, body mass, and heart rate. The study aimed to calculate the metabolic heat production rate by infrared thermal evaluation (ITE) based on the body's thermal balance approach and compare it with the values determined by indirect calorimetry (IC). Fourteen participants volunteered for the study, using a cycling ergometer in a controlled climatic chamber. After the familiarization sessions, maximal O 2 intake levels (VO 2max ) were determined through maximal graded exercise tests. Subsequently, constant work rate exercise tests were performed at 60% of VO 2max for 20 min. The metabolic heat production rates were calculated by IC and ITE for each athlete individually. Respiratory gases were used to determine IC, while body skin and core temperatures, along with physical environmental data, were applied to calculate ITE using the human body thermal balance approximation of ASHRAE. According to the results, heat storage rates were misleading among the body's heat transfer modes, particularly during the first 8 min of the exercise. ITE showed a moderate level of correlation with IC (r: 0.03-0.86) with a higher level of dispersion relative to the mean (CV%: 12-84%). Therefore, a new equation (ITE new ) for the heat storage rates was proposed using the experimental data from this study. The results showed that ITE new provided more precise estimations for the entire exercise period (p > 0.05). Correlations between ITE new and IC values were consistently strong throughout the exercise period (r: 0.62-0.85). It can be suggested that ITE new values can predict IC during the constant work rate steady-state exercise., (© 2024. The Author(s) under exclusive licence to International Society of Biometeorology.)

Introduction: The US Army Load Carriage Decision Aid (LCDA) metabolic model is used by militaries across the globe and is intended to predict physiological responses, specifically metabolic costs, in a wide range of dismounted warfighter operations. However, the LCDA has yet to be adapted for vest-borne load carriage, which is commonplace in tactical populations, and differs in energetic costs to backpacking and other forms of load carriage., Purpose: The purpose of this study is to develop and validate a metabolic model term that accurately estimates the effect of weighted vest loads on standing and walking metabolic rate for military mission-planning and general applications., Methods: Twenty healthy, physically active military-age adults (4 women, 16 men; age, 26 ± 8 yr old; height, 1.74 ± 0.09 m; body mass, 81 ± 16 kg) walked for 6 to 21 min with four levels of weighted vest loading (0 to 66% body mass) at up to 11 treadmill speeds (0.45 to 1.97 m·s -1 ). Using indirect calorimetry measurements, we derived a new model term for estimating metabolic rate when carrying vest-borne loads. Model estimates were evaluated internally by k -fold cross-validation and externally against 12 reference datasets (264 total participants). We tested if the 90% confidence interval of the mean paired difference was within equivalence limits equal to 10% of the measured walking metabolic rate. Estimation accuracy, precision, and level of agreement were also evaluated by the bias, standard deviation of paired differences, and concordance correlation coefficient (CCC), respectively., Results: Metabolic rate estimates using the new weighted vest term were statistically equivalent ( P < 0.01) to measured values in the current study (bias, -0.01 ± 0.54 W·kg -1 ; CCC, 0.973) as well as from the 12 reference datasets (bias, -0.16 ± 0.59 W·kg -1 ; CCC, 0.963)., Conclusions: The updated LCDA metabolic model calculates accurate predictions of metabolic rate when carrying heavy backpack and vest-borne loads. Tactical populations and recreational athletes that train with weighted vests can confidently use the simplified LCDA metabolic calculator provided as Supplemental Digital Content to estimate metabolic rates for work/rest guidance, training periodization, and nutritional interventions., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American College of Sports Medicine.)