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Purpose: Fran is one of the most popular CrossFit benchmark workouts used to control CrossFitters' improvements. Detailed physiological characterization of Fran is needed for a more specific evaluation of CrossFitters' training performance improvements. The aim of the study was to analyze the oxygen uptake ( V ˙ O 2 ) kinetics and characterize the energy system contributions and the degree of postexercise fatigue of the unbroken Fran. Methods: Twenty trained CrossFitters performed Fran at maximal exertion. V ˙ O 2 and heart-rate kinetics were assessed at baseline and during and post-Fran. Blood lactate and glucose concentrations and muscular fatigue were measured at baseline and in the recovery period. Results: A marked increase in V ˙ O 2 kinetics was observed at the beginning of Fran, remaining elevated until the end (V ˙ O 2 peak : 49.2 [3.7] mL·kg−1·min−1, V ˙ O 2 amplitude: 35.8 [5.2] mL·kg−1·min−1, time delay: 4.7 [2.5] s and time constant: 23.7 [11.1] s; mean [SD]). Aerobic, anaerobic lactic, and alactic pathways accounted for 62% (4%), 26% (4%), and 12% (2%) of energy contribution. Reduction in muscle function in jumping ability (jump height: 8% [6%], peak force: 6% [4%], and maximum velocity: 4% [2%]) and plank prone test (46% [20%]) was observed in the recovery period. Conclusions: The Fran unbroken workout is a high-intensity effort associated with an elevated metabolic response. This pattern of energy response highlights the primary contribution of aerobic energy metabolism, even during short and very intense CrossFit workouts, and that recovery can take >24 hours due to cumulative fatigue. [ABSTRACT FROM AUTHOR]

This study aimed to examine the relationship between the maximal lactate accumulation rate (ċLamax) and sprint performance parameters in male competitive swimmers. Seventeen male competitive swimmers volunteered to perform a 20 m maximal front crawl sprint without pushing off the wall from a floating position. ċLamax was determined by the 20-m sprint time and blood lactate measured before and after the 20 m sprint. For the sprint performance parameter, a 50 m time trial with the front crawl swimming stroke was conducted, and the times taken from 0 to 15 m, 15–25 m, 25–35 m, and 35–45 m were analyzed. A semi-tethered swimming test was conducted to investigate the load-velocity profile of each swimmer. From the load-velocity profile, theoretical maximal velocity (V0), maximal load (L0) and relative maximal load (rL0) were examined. The slope of the load-velocity profile was also determined. According to the results, ċLamax correlated with 50 m front crawl performance (r = −.546, p <.05). Moreover, a higher ċLamax was related to faster 0–35 m section time. Furthermore, ċLamax correlated with L0 (r =.837, p <.01), rL0 (r =.820, p <.01), and load-velocity slope (r =.804, p <.01). ċLamax is a good indicator of 50 m front crawl performance in male swimmers, and higher glycolytic power contributes to the faster time at the beginning of the sprint race. ċLamax could also evaluate the ability of a swimmer to apply force to the water during high-intensity swimming. [ABSTRACT FROM AUTHOR]

The article discusses the glycolytic activity following anti-CD19 CAR-T cell infusion in non-Hodgkin lymphoma patients. The study conducted at Tours University Hospital observed an increase in blood lactate levels post-infusion, indicating immune cell activation. High lactate levels were associated with a higher CD8+/CD4+ CAR-T cell ratio and longer circulating CAR-T cell persistence. The findings suggest a glycolytic activity in immune responses post-CAR-T infusion, potentially serving as a marker for metabolic interventions in the future. [Extracted from the article]

Aim: A 15-s all-out sprint cycle test (i.e., νLamax-test) and the post-exercise change in capillary blood lactate concentration is an emerging diagnostic tool that is used to quantify the maximal glycolytic rate. The goal of this study was to determine the relation between 15 s-work, change in capillary blood lactate concentration (∆La) and body composition in a νLamax-test. Method: Fifty cyclists performed a 15 s all-out sprint test on a Cyclus2 ergometer twice after a previous familiarization trial. Capillary blood was sampled before and every minute (for 8 min) after the sprint to determine ∆La. Body composition was determined employing InBody720 eight-electrode impedance analysis. Result: Simple regression models of fat-free mass (FFM) and also the product of FFM and ∆La showed similar ability to predict 15 s-work (R2 = 0.79; 0.82). Multiple regression combining both predictors explains 93% of variance between individuals. No differences between males and females were found regarding 15 s-work relative to the product of fat-free mass and ∆La. Considering pairs of similar FFM, a change 1 mmol/l of ∆La is estimated to be equal to 12 J/kg in 15 s-work (R2 = 0.85). Discussion: Fifteen s-work is both closely related to FFM and also the product of ∆La and lactate-distribution space approximated by FFM. Differences in 15 s-work between males and females disappear when total lactate production is considered. Considering interindividual differences, the mechanical energy equivalent of blood lactate accumulation seems a robust parameter displaying a clear relationship between ∆La and 15 s-work relative to FFM. [ABSTRACT FROM AUTHOR]

This study aimed to compare acute physiological responses during the W prime (W´) balance training model (W´BAL-INT) with performance in the critical power test (CPTest). Additionally, the study sought to determine the extent of neuromuscular and metabolic fatigue associated with severe and extreme intensity domains. Fourteen road master cyclists (13 male, 1 female) completed graded incremental exercise tests to determine their maximum oxygen uptake and 12-, 7- and 3-min maximal efforts to assess CP and W´ (CPTest). Additionally, they participated in a reconstitutive intermittent training session following the W´BAL-INT model. Physiological responses including oxygen uptake (V̇O2), the heart rate (HR), blood lactate (BLa¯) concentration, and perceptual responses (RPE), were measured and compared to CPTest performance data. The W´BAL-INT induced steady-state physiological responses in V̇O2mean (F = 0.76, p = 0.655) and absolute HR, relative HR and HRCP (F = 0.70, p = 0.704; F = 1.11, p = 0.359; F = 1.70, p = 0.095, respectively) comparable to CPTest. During the 3-min work intervals in the training session, V̇O2 was stable and similar to V̇O2peak (54.2 ± 6.7 to 59.3 ± 4.9 ml·kg-1·min-1) in the CPTest. Furthermore, 4-min rest intervals facilitated recovery up to moderate fatigue levels (80-100% of W´ balance). HR responses were sensitive to interval intensity and accumulated time. Meanwhile, BLa¯ responses and the RPE increased fatigue development during W´BAL-INT. The W´BAL-INT training model generates consistent physiological responses in mean oxygen kinetics, the percentage of CP and the HR, similar to those observed during the CPTest. However, different physiological responses were observed in peak oxygen kinetics and W´ energy balance. [ABSTRACT FROM AUTHOR]

Background Objectives Animals Methods Results Conclusions and Clinical Importance Workload associated with the high frequency Colombian Paso Fino gait has not been evaluated.To determine the oxygen consumption (V̇O2), heart rate (HR), stride frequency: breathing ratio, and hematology associated with the Paso Fino gait, including whether exercise‐induced pulmonary hemorrhage (EIPH) occurs.Eleven Paso Fino horses.Prospective cohort study. Horses performed a standardized Paso Fino gait test across a wooden sounding board, simulating competition. V̇O2 and ventilatory parameters (tidal volume [VT]; peak inspiratory and expiratory airflows [PkV̇I, PkV̇E]; respiratory rate [RR], minute ventilation [V̇E]) were measured using a portable ergospirometry facemask. Heart rate was measured using electrocardiograms. Post‐exercise lactate, hematocrit, bicarbonate, pH, electrolytes, and biochemistry concentrations were measured. EIPH was assessed via tracheobronchoscopy. Four horses completed a secondary high‐intensity gallop to elicit peak V̇O2 for comparative purposes.Median [IQR] mean individual HR during the Paso Fino gait was 190 [178, 201] bpm. Relative V̇O2 measured 49.8 [48.4, 59.5] mL/(kg min; VT = 8.6 [8.0, 10.7] L; RR = 87.1 [75.4, 99.5] bpm; V̇E = 869 [740, 902] L/min; PkV̇I = 33.4 [32.7, 37.2] L/s; PkV̇E = 44.2 [40.3, 46.0] L/s). Horses took 2.8 [2.7, 2.9] strides/second and had a stride frequency: breathing ratio of 2.0 [1.8, 2.3]. Post‐exercise blood lactate concentration and hematocrit measured 2.7 mmol/L and 50% respectively. Three horses showed endoscopic evidence of Grade‐1 EIPH. The Paso Fino gait V̇O2 and HR equaled 79% V̇O2pk and 91% maximal HR, respectively, based on the high‐intensity gallop.The Paso Fino gait represents submaximal exercise based on V̇O2 < V̇O2pk and blood lactate. [ABSTRACT FROM AUTHOR]

This study compared the effects of High-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on blood lactate clearance. 21 adult males were equally and randomly assigned to the HIIT and MICT groups, and completed 8 weeks of training. Before the training intervention, after 4 weeks and 8 weeks of training, all subjects were tested for blood lactate levels between 0 and 55 min after the same high-intensity test. The results show that after 8 weeks, blood lactate levels were significantly lower than pre-tests in both the HIIT and MICT groups at "0-55 min" after high-intensity test (p < 0.05), and the blood lactate clearance percentage at15-min and 30-min in both groups were significantly higher than the pre-tests (P < 0.01). The blood lactate levels in the HIIT group were significantly lower than those in the MICT group at 15 min and 30 min after test (P < 0.05), and the blood lactate clearance percentage at 30 min in the HIIT group was significantly higher than those in the MICT group (P < 0.05). In conclusion, both HIIT and MICT enhance blood lactate clearance in adult males post high-intensity test, with HIIT demonstrating superior effectiveness, making it a viable alternative to MICT. [ABSTRACT FROM AUTHOR]

Background: Pulmonary oedema is a feared and difficult to predict complication of severe malaria that can emerge after start of antimalarial treatment. Proinflammatory mediators are thought to play a central role in its pathogenesis. Methods: An exploratory study was conducted to evaluate the predictive capacity of biomarkers for development of clinical pulmonary oedema in patients with severe falciparum malaria at two hospitals in Bangladesh. Plasma concentrations of interleukin-6 (IL-6), IL-8, tumour necrosis factor (TNF), soluble Receptor of Advanced Glycation End-products (sRAGE), surfactant protein-D (SP-D), club cell secretory protein (CC16), and Krebs von den Lungen-6 (KL-6) on admission were compared with healthy controls. Correlations between these biomarker and plasma lactate and Plasmodium falciparum histidine-rich protein 2 (PfHRP2) levels were evaluated. Receiver Operating Characteristic (ROC) curves were constructed to assess the predictive capacity for clinical pulmonary oedema of the biomarkers of interest. Results: Of 106 screened patients with falciparum malaria, 56 were classified as having severe malaria with a mortality rate of 29%. Nine (16%) patients developed clinical pulmonary oedema after admission. Plasma levels of the biomarkers of interest were higher in patients compared to healthy controls. IL-6, IL-8, TNF, sRAGE, and CC16 levels correlated well with plasma PfHRP2 levels (rs = 0.39; P = 0.004, rs = 0.43; P = 0.001, rs = 0.54; P < 0.001, rs = 0.44; P < 0.001, rs = 0.43; P = 0.001, respectively). Furthermore, IL-6 and IL-8 levels correlated well with plasma lactate levels (rs = 0.37; P = 0.005, rs = 0.47; P < 0.001, respectively). None of the biomarkers of interest had predictive capacity for development of clinical pulmonary oedema. Conclusions: IL-6, IL-8, TNF, sRAGE, SP-D, CC16 and KL-6 cannot be used in predicting clinical pulmonary oedema in severe malaria patients. [ABSTRACT FROM AUTHOR]

Introduction: Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) has been established as an effective treatment for peritoneal cancer (PC). However, this kind of combination therapy is associated with a high lactate level. Moreover, studies have suggested that the rate of complications early after surgery directly increased with elevated lactate levels. Glucose-insulin-potassium (GIP), a potent cardioprotective intervention, has been demonstrated to adjust blood glucose (BG) levels and reduce lactate levels. However, the insulin-glucose ratio should be adjusted according to the surgery performed. Here, we aimed to evaluate the advantages of using modified GIP during CRS/HIPEC to reduce the lactate level at the end of surgery and further reduce the incidence of early postoperative complications. Methods and analysis: The modified GIP versus conventional management during surgery study is a single-center, randomized, single-blinded outcome assessment clinical trial of 80 patients with PC who are between 18 and 64 years old and undergoing CRS/HIPEC. Participants will be randomly allocated to receive modified GIP or conventional treatment (1:1). The primary outcome will be the plasma lactate level at the end of surgery. The secondary outcomes will include the highest levels and fluctuation ranges of lactate and BG during surgery, extubation time, APACHE-II score 24 h after surgery, postoperative defecation and exhaust time, postoperative lactate clearance time, postoperative liver and kidney function, incidence of complications within 7 days after surgery, length of intensive care unit stay (LIS), length of hospital stay (LHS), and total cost of hospitalization. Ethics and dissemination: The trial protocol was approved by the Scientific Research Ethics Committee of Beijing Shijitan Hospital Affiliated with Capital Medical University, approval number sjtky11-1x-2022(118). The results will be published in international peer-reviewed journals. Trial registration: ChiCTR2200057258. Registered on March 5, 2022. [ABSTRACT FROM AUTHOR]

Lactate plays a critical role as an energy substrate, metabolite, and signaling molecule in hepatocellular carcinoma (HCC). Intracellular lactate‐derived protein lysine lactylation (Kla) is identified as a contributor to the progression of HCC. Liver cancer stem cells (LCSCs) are believed to be the root cause of phenotypic and functional heterogeneity in HCC. However, the impact of Kla on the biological processes of LCSCs remains poorly understood. Here enhanced glycolytic metabolism, lactate accumulation, and elevated levels of lactylation are observed in LCSCs compared to HCC cells. H3K56la was found to be closely associated with tumourigenesis and stemness of LCSCs. Notably, a comprehensive examination of the lactylome and proteome of LCSCs and HCC cells identified the ALDOA K230/322 lactylation, which plays a critical role in promoting the stemness of LCSCs. Furthermore, this study demonstrated the tight binding between aldolase A (ALDOA) and dead box deconjugate enzyme 17 (DDX17), which is attenuated by ALDOA lactylation, ultimately enhancing the regulatory function of DDX17 in maintaining the stemness of LCSCs. This investigation highlights the significance of Kla in modulating the stemness of LCSCs and its impact on the progression of HCC. Targeting lactylation in LCSCs may offer a promising therapeutic approach for treating HCC. [ABSTRACT FROM AUTHOR]

Obstacle course races (OCR) have experienced significant growth in recent years, with millions of participants worldwide. However, there is limited research on the specific physiological demands and injury prevention strategies required for these events. This study aimed to analyze the physiological responses and injury risks in participants of a 5 km (Sprint) and 13 km (Super) OCR. Sixty-eight participants were assessed for cortical arousal, leg strength, isometric handgrip strength, blood lactate, heart rate, blood oxygen saturation, body temperature, urine composition, spirometry values, hamstring flexibility, lower limb stability, foot biomechanics, and scapular kinematics, one hour before and immediately after the races. The results showed a significant decrease in leg strength (Sprint: r = −0.56, p < 0.01; Super: r = −0.54, p = 0.01) and urine pH (Sprint: r = −0.70, p = 0.03; Super: r = −0.67, p = 0.01) in both distances, with increases in urine colour, protein, and glucose (Sprint: p < 0.04). In the 13 km race, lower limb stability decreased significantly post-race (r = −0.53, p = 0.01). Positive correlations were found between performance and pre-race handgrip strength (Sprint: r = 0.71, p = 0.001; Super: r = 0.72, p = 0.01) and spirometry values (FVC, FEF 25–75%, FEV1) (Sprint: r = 0.52, p = 0.031; Super: r = 0.48, p = 0.035). Thermoregulation capacity, reflected in a higher pre-race body temperature and lower post-race body temperature, also correlated with improved performance (r = 0.49, p = 0.046). Injury risk increased post-race, with a significant decline in lower limb stability (p < 0.05). These findings highlight the importance of targeted training programs, focusing on grip strength, leg strength, respiratory muscle training, and hydration strategies to optimize performance and reduce injury risk in OCR athletes. [ABSTRACT FROM AUTHOR]

Background and purpose: Among patients with solid tumors, those with breast cancer (BC) experience the most severe psychological issues, exhibiting a high global prevalence of depression that negatively impacts prognosis. Depression can be easily missed, and clinical markers for its diagnosis are lacking. Therefore, this study in order to investigate the diagnostic markers for BC patients with depression and anxiety and explore the specific changes of metabolism. Method and results: Thirty-eight BC patients and thirty-six matched healthy controls were included in the study. The anxiety and depression symptoms of the participants were evaluated by the 17-item Hamilton Depression Scale (HAMD-17) and Hamilton Anxiety Scale (HAMA). Plasma levels of glial fibrillary acidic protein (GFAP) and lipocalin-2 (LCN2) were evaluated using enzyme linked immunosorbent assay, and plasma lactate levels and metabolic characteristics were analyzed. Conclusion: This study revealed that GFAP and LCN2 may be good diagnostic markers for anxiety or depression in patients with BC and that plasma lactate levels are also a good diagnostic marker for anxiety. In addition, specific changes in metabolism in patients with BC were preliminarily explored. [ABSTRACT FROM AUTHOR]

Background: Early recognition of sepsis by the EMS (Emergency Medical Services), along with communicating this concern to the emergency department, could improve patient prognosis and outcome. Knowledge is limited about the performance of sepsis identification screening tools in the EMS setting. Research is also limited on the effectiveness of prehospital use of blood tests for sepsis identification. Integrating blood analyses with screening tools could improve sepsis identification, leading to prompt interventions and improved patient outcomes. Aim: The aim of the present study is firstly to evaluate the performance of various screening tools for sepsis identification in the EMS setting and secondly to assess the potential improvement in accuracy by incorporating blood analyses. Methods: This is a retrospective observational cohort study. The data were collected from prehospital and hospital medical records in Region Halland. Data on demographics, vital signs, blood tests, treatment, and outcomes were collected from patients suspected by EMS personnel of having infection. The data were analysed using Student's t-test. Sensitivity, specificity, positive predictive value, negative predictive value and odds ratio were used to indicate accuracy and predictive value. Results: In total, 5,405 EMS missions concerning 3,225 unique patients were included. The incidence of sepsis was 9.8%. None of the eleven tools included had both high sensitivity and specificity for sepsis identification. White blood cell (WBC) count was the blood analysis with the highest sensitivity but the lowest specificity for identifying sepsis. Adding WBC, C-reactive protein (CRP) or lactate to the National Early Warning Score (NEWS) increased the specificity to > 80% but substantially lowered the sensitivity. Conclusions: Identifying sepsis in EMS settings remains challenging, with existing screening tools offering limited accuracy. CRP, WBC, and lactate blood tests add minimal predictive value in distinguishing sepsis or determining non-conveyance eligibility. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effect of two protocols of high-intensity interval exercise (HIIE) on performance fatigability and its neural and muscular determinants. On different days, 14 healthy males performed two HIIE protocols with different work and recovery durations (matched for total duration, work and recovery intensities, and density): 1) 4 × 4 min at 90% HRpeak,180-s recovery at 70% HRpeak; and 2) 16 × 1 min at 90% HRpeak, 45-s recovery at 70% HRpeak. Pre- to post-HIIE reduction in maximal voluntary isometric contraction (MVIC) was used as marker of performance fatigability, while voluntary activation (VA) and potentiated quadriceps twitch force (Qtw) as markers of the neural (i.e. central fatigue) and muscular (i.e. peripheral fatigue) determinants, respectively. In addition, pre- to post-HIIE reduction in twitch force stimulated at 100 Hz (Qtw100) and 10:100 Hz ratio (Qtw10:Qtw100) were used as markers of high- and low-frequency performance fatigability, respectively. The MVIC, VA, Tw, Qtw100, and Qtw10:Qtw100 ratio decreased similarly from pre- to post-HIIE in both HIIE protocols (p < .05). The rating of perceived effort, blood pH, and plasma lactate responses were similar between HIIE protocols (p > .05), but the heart rate was higher in the longer HIIE protocol (p < .05). In conclusion, performance fatigability and its neural and muscular determinants seemed to be independent of the work and recovery durations of the HIIE, at least when HIIE protocols were matched for total work duration, work and recovery intensities, and density. Further, HIIE with long work and recovery might be preferable when the intention is to stress the chronotropic response. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of phentolamine adjuvant therapy on hemodynamics and cardiac function in patients with sepsis-induced myocardial injury. Methods: A total of 96 patients with sepsis-induced myocardial injury between January 2019 and October 2023 admitted in Hangzhou Fuchun Traditional Chinese Orthopedic Hospital, Hangzhou, Zhejiang, China were randomly and equally assigned to control and study groups. The control group received routine treatment while the study group received phentolamine 5 mg/h for 24 h in addition to routine treatment. Blood lactate levels before and after treatment were compared. Intrathoracic blood volume index (ITBVI), systemic vascular resistance index (SVRI), heart rate (HR), mean arterial pressure (MAP), cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP), as well as cardiac index (CI), left ventricular ejection fraction (LVEF), left ventricular end-systolic diameter (LVESD), and left ventricular end-diastolic diameter (LVEDD), were also evaluated before and after treatment. Furthermore, 28-day survival rates and intensive care unit (ICU) stay time were compared. Results: The study group showed significantly lower blood lactate levels at 12, 48, and 72 h after treatment compared to control group (p < 0.05). The study group showed significantly higher levels of MAP, ITBVI, SVRI, CI, and LVEF; and significantly lower levels of HR, LVESD, LVEDD, cTnI, and NTproBNP after 7 days than the control group (p < 0.05). No deaths occurred within 7 days after treatment in either group. However, the study group exhibited significantly lower ICU stay time and 28-day mortality than the control group (p < 0.05). Conclusions: Phentolamine adjuvant therapy significantly improves hemodynamics, enhances cardiac function, mitigates myocardial injury, and restores blood lactate levels in patients with sepsis-induced myocardial injury. Longer follow-up would be necessary to evaluate long-term effect and potential complications of phentolamine-adjuvant therapy. [ABSTRACT FROM AUTHOR]

This present study aims to investigate the Donation after Circulatory Death (DCD) procedure and the ischemia-reperfusion injury that occurs during organ preservation by examining the correlation between lactate levels during normothermic reperfusion (NrP) and the positive criterion of eligibility and suitability of the organ for DCD transplantation. This retrospective study was approved by the Ethics Committee of our institution. Data were retrieved from DCD kidney donors who were patients admitted to the Intensive Care Unit (ICU) of Ospedale Civile di Baggiovara, Modena (Italy), between 2018 and 2019 and comprised various parameters related to DCD donors, including age, reason for ICU admission, administration of noradrenaline infusion exceeding the dosage of 0.3 mcg/kg/min, duration of ICU stay, lactate levels during normothermic reperfusion (NrP), blood flow during NrP, time of NrP and the criterion of eligibility and suitability of the organ for transplantation as per the Karpinski score. Additionally, when available, short-term information regarding graft complications or organ rejection was also recorded. This manuscript adheres to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Univariate analysis showed that T0 lactates (odds ratio (OR): 2.20, 95% confidence interval (CI) 1.04-4.71; p = 0.038) and age (OR: 0.69, 95% CI 0.51-0.93; p = 0.016) were significantly associated with the outcome of organ suitability for transplantation. Additionally, lactate levels exhibited a decrease during NrP time, as indicated by a linear mixed model effect, with p-values of 0.004 for the outcome of organ suitability for transplantation and 0.004 for time. Statistical analyses indicate no negative correlation between an increase in lactate levels in the blood during explantation and negative outcomes. Conversely, higher levels of lactate in younger and healthier patients may suggest better mitochondrial function, while a significant decrease in lactate levels may indicate reduced organ damage and increased suitability for transplantation. [ABSTRACT FROM AUTHOR]

OBJECTIVES: It is crucial to promptly identify high-mortality patients in emergency departments and initiate their treatment as soon as possible. Although many parameters have been studied to select patients with high mortality, no comprehensive evaluation exists in previous literature on these parameters in critically ill patients, regardless of patient groups. The aim of this study is to evaluate the Glasgow Coma Scale (GCS), quick Sepsis-related Organ Failure Assessment (qSOFA), blood gas base excess (BE), and blood gas lactate in predicting mortality in critically ill patients admitted to the emergency department. METHODS: This prospective observational cohort study included adult patients with Emergency Severity Index 1-2 (critically ill) admitted to the emergency department. All patients were evaluated by the physician within 10 min, and blood gas samples were taken. The data collection forms recorded the patients' GCS and qSOFA scores at the time of first evaluation by the physician. The qSOFA score assessment was performed in all patients with ESI levels 1 and 2, regardless of whether infective pathology was suspected. Blood gas BE and lactate values were also from laboratory test results. Patients or their relatives were contacted by phone at the end of the 1st month to obtain information about the clinical condition (survival or mortality). RESULTS: A total of 868 patients were included, with 163 deaths observed within 30 days. GCS score, qSOFA score, and lactate value were significant in predicting mortality within 30 days. While the BE value was significant for predicting 30-day mortality for values equal to or below the lower limit of -1.5 (P < 0.001), it was not significant for values equal to or above the upper limit of +3 (P > 0.05). The most successful prediction model for predicting 30-day mortality was found to be qSOFA with a cutoff value of ≥1. CONCLUSION: In emergency departments, each of the GCS, qSOFA scores, BE, and lactate values can be used independently as a practical mortality prediction model in critically ill patients. Among these four models, qSOFA is the most successful practical mortality prediction model in critically ill patients. [ABSTRACT FROM AUTHOR]

Context: In Australia, approximately 53% of lamb deaths are caused by dystocia. One of the main welfare concerns in the sheep industry is under- and overfeeding ewes, which may be contributing to cases of dystocia. Aims: This pilot study aimed to investigate how increasing energy intake affects the duration of parturition and predictors of lamb survival. Methods: On Day 100 of gestation (dG), 20 twin-bearing and 10 singleton Merino ewes were selected and allocated to three treatment groups; (1) singleton ewes fed at 1.0× maintenance levels (n = 10); (2) twin-bearing ewes fed at 1.0× maintenance levels (n = 10) or (3) twin-bearing ewes fed at 1.25× maintenance (n = 10). Ewes were housed indoors in individual pens. Urine and blood were sampled from ewes on dG 130, 140, then daily from dG 145 through to parturition, and blood was sampled at the onset of parturition and 30 min post-partum. Urine was analysed for pH and blood was analysed for metabolic parameters, mineral concentration and acid–base balance. Predictors of lamb survival from birth to 24 h consisted of weight, rectal temperature, blood glucose and lactate, and body morphology. Key results: Serum calcium in late gestation and blood base excess pre-parturition were higher in Singletons 1M compared with Twins 1M (P < 0.05). The Twins 1.25M group took longer to give birth to the first-born lamb (104.4 ± 21.1 min) compared with the Twins 1M group (44.1 ± 6.6 min; P = 0.015). There were no differences in the predictors of lamb survival measures between the twin-bearing groups (P > 0.05). Conclusions: Ewes from the Twins 1.25M group took significantly longer to give birth to the first-born lamb. There were no other significant findings between the twin-bearing groups, including lamb liveweight, however, lambs born to ewes from the Twins 1.25 group were numerically heavier, which may explain the increase in parturition length. Implications: Feeding ewes above maintenance did not provide any production benefits to metabolic health or any other physiological parameters. Producers should avoid overfeeding ewes during late gestation. Around half of lamb deaths in Australia are caused by long/difficult births and the diet of the ewe in late pregnancy might be contributing to this. We tested this by comparing diets with different energy levels in twin-bearing ewes. We found that increasing the energy levels of the diet by 25% increased the duration of time for ewes to give birth to the first-born lamb. This indicates that overfeeding ewes may not have any production benefits. [ABSTRACT FROM AUTHOR]

Purpose: The aims of the present study were to investigate blood lactate kinetics following high intensity exercise and identify the physiological determinants of 800 m running performance. Methods: Fourteen competitive 800 m runners performed two running tests. First, participants performed a multistage graded exercise test to determine physiological indicators related to endurance performance. Second, participants performed four to six 30-s high intensity running bouts to determine post-exercise blood lactate kinetics. Using a biexponential time function, lactate exchange ability (γ1), lactate removal ability (γ2), and the quantity of lactate accumulated (QLaA) were calculated from individual blood lactate recovery data. Results: 800 m running performance was significantly correlated with peak oxygen consumption (r = −0.794), γ1 and γ2 at 800 m race pace (r = −0.604 and −0.845, respectively), and QLaA at maximal running speed (r = −0.657). V ˙ O2peak and γ2 at 800 m race pace explained 83% of the variance in 800 m running performance. Conclusion: Our results indicate that (1) a high capacity to exchange and remove lactate, (2) a high capacity for short-term lactate accumulation and, (3) peak oxygen consumption, are critical elements of 800 m running performance. Accordingly, while lactate has primarily been utilized as a performance indicator for long-distance running, post-exercise lactate kinetics may also prove valuable as a performance determinant in middle-distance running. [ABSTRACT FROM AUTHOR]

Aim: To investigate how delayed post‐exercise carbohydrate intake affects muscle glycogen, metabolic‐ and mitochondrial‐related molecular responses, and subsequent high‐intensity interval exercise (HIIE) capacity. Methods: In a double‐blind cross‐over design, nine recreationally active men performed HIIE (10 × 2‐min cycling, ~94% W˙peak) in the fed state, on two occasions. During 0–3 h post‐HIIE, participants drank either carbohydrates ("Immediate Carbohydrate" [IC], providing 2.4 g/kg) or water ("Delayed Carbohydrate" [DC]); total carbohydrate intake over 24 h post‐HIIE was matched (~7 g/kg/d). Skeletal muscle (sampled pre‐HIIE, post‐HIIE, +3 h, +8 h, +24 h) was analyzed for whole‐muscle glycogen and mRNA content, plus signaling proteins in cytoplasmic‐ and nuclear‐enriched fractions. After 24 h, participants repeated the HIIE protocol until failure, to test subsequent HIIE capacity; blood lactate, heart rate, and ratings of perceived effort (RPE) were measured throughout. Results: Muscle glycogen concentrations, and relative changes, were similar between conditions throughout (p > 0.05). Muscle glycogen was reduced from baseline (mean ± SD mmol/kg dm; IC: 409 ± 166; DC: 352 ± 76) at post‐HIIE (IC: 253 ± 96; DC: 214 ± 82), +3 h (IC: 276 ± 62; DC: 269 ± 116) and + 8 h (IC: 321 ± 56; DC: 269 ± 116), returning to near‐baseline by +24 h. Several genes (PGC‐1ɑ, p53) and proteins (p‐ACCSer79, p‐P38 MAPKThr180/Tyr182) elicited typical exercise‐induced changes irrespective of condition. Delaying carbohydrate intake reduced next‐day HIIE capacity (5 ± 3 intervals) and increased RPE (~2 ratings), despite similar physiological responses between conditions. Conclusion: Molecular responses to HIIE (performed in the fed state) were not enhanced by delayed post‐exercise carbohydrate intake. Our findings support immediate post‐exercise refueling if the goal is to maximize next‐day HIIE capacity and recovery time is ≤24 h. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate propofol as an anesthetic and its effects on physiology and histology in Ictalurus punctatus. To determine the ideal concentration, juvenile of I. punctatus (96.60 ± 27.70 g) were used, submitted to different concentrations of the anesthetic: 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, and 6.0 mg L−1. The concentration evaluated as ideal was 2.5 mg L−1. To evaluate the physiological and histological effects of propofol exposure, juvenile of I. punctatus (99.71 ± 26.38 g) were sampled immediately (T0) and 30 min after anesthesia (T30) with 2.5 mg L−1, had blood, liver, and gill samples collected. The exposure of the animals to propofol in both treatments (T0 and T30) caused increases in plasma glucose and lactate levels (p < 0.05) but prevented an increase in cortisol (p > 0.05). The histological study showed mild to moderate changes in the gills (congestion in the lamellar vessels and central vein and epithelial elevation) and moderate and severe changes in the liver (congestion and degeneration). This study concludes that the concentration of 2.5 mg L−1 of propofol provides safe anesthesia for I. punctatus and prevents increased plasma cortisol levels. [ABSTRACT FROM AUTHOR]

Objectives. This study aimed to examine the physiological response to speed endurance soccer training (SEST), which involved the measurement of heart rate (HR), blood lactate (LAC), and blood pressure (BP) are measured during the four-week intervention period. Materials and methods. The one-group pretest-posttest pre-experimental design was used in this study. The study comprised 15 male amateur soccer players with an average age of 16.13 ± 0.52 years. The participants’ mean height was 167.4 ± 4.63 cm, weight was 57.69 ± 12.11 kg, and BMI was 20.44 ± 3.45 kg/m² . The data findings are presented using the mean and standard deviation. The paired t-test was employed to assess the impact of each group. The threshold for statistical significance was set at a p-value of less than 0.05. The effect size (ES) was calculated using Cohen’s ES as a metric to quantify the magnitude of the difference between the pretest and posttest stages. Results. The HR results monitoring during the intervention period were in the high-intensity zone, with an average of 91.67 ± 0.6 % and a HR of 187.67 ± 1.24 bpm. No significant change was observed in the heart rate response from baseline to end of intervention. The LAC results showed that the lactate level was in the high category, namely an average of 11.03 ± 1.3 mmol∙L-1. BP indicated a significant difference between pretest and posttest (p ≤ 0.05). The systolic blood pressure (SBP) demonstrated an increase of Δ % = 0.95, while the diastolic blood pressure (DBP) showed an increase of Δ % = 1.39. Conclusions. The findings of this study indicate that SEST has a notable effect on the body’s physiological functions, namely on the cardiovascular system, anaerobic metabolism, and blood pressure. This effect was observed over a period of four weeks in amateur soccer players. [ABSTRACT FROM AUTHOR]

Aims: Heart failure with preserved ejection fraction (HFpEF) is associated with an array of central and peripheral haemodynamic and metabolic changes. The exact pathogenesis of exercise limitation in HFpEF remains uncertain. Our aim was to compare lactate accumulation and central haemodynamic responses to exercise in patients with HFpEF, non‐cardiac dyspnoea (NCD), and healthy volunteers. Methods and results: Right heart catheterization with mixed venous blood gas and lactate measurements was performed at rest and during symptom‐limited supine exercise. Multivariable analyses were conducted to determine the relationship between haemodynamic and biochemical parameters and their association with exercise capacity. Of 362 subjects, 198 (55%) had HFpEF, 103 (28%) had NCD, and 61 (17%) were healthy volunteers. This included 139 (70%) females with HFpEF, 77 (75%) in NCD (P = 0.41 HFpEF vs. NCD), and 31 (51%) in healthy volunteers (P < 0.001 HFpEF vs. volunteers). The median age was 71 (65, 75) years in HFpEF, 66 (57, 72) years in NCD, and 49 (38, 65) years in healthy volunteers (HFpEF vs. NCD or volunteer, both P < 0.001). Peak workload was lower in HFpEF compared with healthy volunteers [52 W (interquartile range 31–73), 150 W (125–175), P < 0.001], but not NCD [53 W (33, 75), P = 0.85]. Exercise lactate indexed to workload was higher in HFpEF at 0.08 mmol/L/W (0.05–0.11), 0.06 mmol/L/W (0.05–0.08; P = 0.016) in NCD, and 0.04 mmol/L/W (0.03–0.05; P < 0.001) in volunteers. Exercise cardiac index was 4.5 L/min/m2 (3.7–5.5) in HFpEF, 5.2 L/min/m2 (4.3–6.2; P < 0.001) in NCD, and 9.1 L/min/m2 (8.0–9.9; P < 0.001) in volunteers. Oxygen delivery in HFpEF was lower at 1553 mL/min (1175–1986) vs. 1758 mL/min (1361–2282; P = 0.024) in NCD and 3117 mL/min (2667–3502; P < 0.001) in the volunteer group during exercise. Predictors of higher exercise lactate levels in HFpEF following adjustment included female sex and chronic kidney disease (both P < 0.001). Conclusions: HFpEF is associated with reduced exercise capacity secondary to both central and peripheral factors that alter oxygen utilization. This results in hyperlactataemia. In HFpEF, plasma lactate responses to exercise may be a marker of haemodynamic and cardiometabolic derangements and represent an important target for future potential therapies. [ABSTRACT FROM AUTHOR]

Background: Hypoxia and hyperoxia can affect the acute psycho-physiological response to exercise. Recording various perceptual responses to exercise is of particular importance for investigating behavioral changes to physical activity, given that the perception of exercise-induced pain, discomfort or unpleasure, and a low level of exercise enjoyment are commonly associated with a low adherence to physical activity. Therefore, this study aimed to compare the acute perceptual and physiological responses to aerobic exercise under intermittent hypoxia-hyperoxia (IHHT), hypoxia-normoxia (IHT), and sustained normoxia (NOR) in young, recreational active, healthy males. Methods: Using a randomized, single-blinded, crossover design, 15 males (age: 24.5 ± 4.2 yrs) performed 40 min of submaximal constant-load cycling (at 60% peak oxygen uptake, 80 rpm) under IHHT (5 × 4 min hypoxia and hyperoxia), IHT (5 × 4 min hypoxia and normoxia), and NOR. Inspiratory fraction of oxygen during hypoxia and hyperoxia was set to 14% and 30%, respectively. Heart rate (HR), total hemoglobin (tHb) and muscle oxygen saturation (SmO2) of the right vastus lateralis muscle were continuously recorded during cycling. Participants' peripheral oxygen saturation (SpO2) and perceptual responses (i.e., perceived motor fatigue, effort perception, perceived physical strain, affective valence, arousal, motivation to exercise, and conflict to continue exercise) were surveyed prior, during (every 4 min), and after cycling. Prior to and after exercise, peripheral blood lactate concentration (BLC) was determined. Exercise enjoyment was ascertained after cycling. For statistical analysis, repeated measures analyses of variance were conducted. Results: No differences in the acute perceptual responses were found between conditions (p ≥ 0.059, ηp2 ≤ 0.18), while the physiological responses differed. Accordingly, SpO2 was higher during the hyperoxic periods during the IHHT compared to the normoxic periods during the IHT (p < 0.001, ηp2 = 0.91). Moreover, HR (p = 0.005, ηp2 = 0.33) and BLC (p = 0.033, ηp2 = 0.28) were higher during IHT compared to NOR. No differences between conditions were found for changes in tHb (p = 0.684, ηp2 = 0.03) and SmO2 (p = 0.093, ηp2 = 0.16). Conclusion: IHT was associated with a higher physiological response and metabolic stress, while IHHT did not lead to an increase in HR and BLC compared to NOR. In addition, compared to IHT, IHHT seems to improve reoxygenation indicated by a higher SpO2 during the hyperoxic periods. However, there were no differences in perceptual responses and ratings of exercise enjoyment between conditions. These results suggest that replacing normoxic by hyperoxic reoxygenation-periods during submaximal constant-load cycling under intermittent hypoxia reduced the exercise-related physiological stress but had no effect on perceptual responses and perceived exercise enjoyment in young recreational active healthy males. [ABSTRACT FROM AUTHOR]

This study aimed to monitor the oxygenation and blood supply in three quadriceps muscles [the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF)] during squatting exercise to exhaustion. Eighteen young resistance-trained males performed five sets of 15 back squats in a Smith machine, with two warm-up sets [at 14% and 45% of the 15-repetition maximum (15RM)] and three main sets at 100% of the 15RM. Three near-infrared spectroscopy devices were attached to the VL, VM, and RF to record the muscle oxygen saturation (SmO2) and total hemoglobin (tHb, an index of muscle blood supply). The blood lactate concentration was measured after each set with a portable analyzer. The SmO2 and tHb data were analyzed by repeated-measures two-way ANOVA (muscle × set). Lactate data were analyzed by repeated-measures one-way ANOVA. The statistical significance was set at α = 0.05. The SmO2 dropped during each set (hitting zero in many instances) and was reinstated during recovery. The three main sets caused severe deoxygenation in the VL and VM, as opposed to moderate deoxygenation in the RF. From one set to the next, the initial value and the drop in the SmO2 increased, whereas the final SmO2 value decreased. The tHb increased in the VL, did not change considerably in the VM, and decreased in the RF during each set. The blood lactate concentration increased gradually from one set to the next, reaching about 10 mmol/L. These findings show pronounced differences in the physiological and metabolic responses of three quadriceps muscles to squatting exercise, thus highlighting the importance of studying such responses at multiple sites. [ABSTRACT FROM AUTHOR]

The primary aim of the study was to assess differences in strength performance, neuromuscular fatigue, and perceived exertion across phases of the menstrual cycle [MC; early follicular (eFP), late follicular (lFP), and mid-luteal phase (mLP)] and oral contraceptives [OCs; active pill phase (aPP) and nonactive pill phase (nPP)]. The secondary aim was to analyze the influence of fluctuating serum 17β-estradiol and progesterone concentrations on these parameters in naturally menstruating women. Thirty-four women (21 with a natural MC and 13 using OCs) completed three or two experimental sessions, respectively. Mean propulsive velocity (MPVmean) and total number of repetitions (REPtotal) were assessed during a power [3 × 8 at 60% 1RM (one-repetition maximum)] and hypertrophy squat loading (3 sets to failure at 70% 1RM), respectively. Changes in bench press and squat MPV at 60% 1RM in response to the loadings were used as surrogates for nonlocal and local fatigue, respectively. Total blood lactate accumulation (BLAA) and markers of perceived exertion were assessed in each session. No significant differences between any of the MC or OC phases were observed for MPVmean, REPtotal, nonlocal and local fatigue, and markers of perceived exertion (all P > 0.050). A higher intraindividual 17β-estradiol concentration was significantly associated with a lower MPVmean (P = 0.019). BLAA was significantly higher in the lFP than in the mLP (P = 0.019) and negatively associated with the intraindividual progesterone concentration (P = 0.005). Although 17β-estradiol may negatively influence the MPV, it appears that fluctuations of both sex hormones across the MC and OC phases are not prominent enough to induce significant or practically relevant changes in the assessed parameters. NEW & NOTEWORTHY: Although a high intraindividual 17β-estradiol concentration was associated with a lower movement velocity, markers of strength performance and surrogates for nonlocal and local fatigue remained unaffected by MC and OC phases. Blood lactate accumulation was significantly reduced in the mLP. Furthermore, our findings suggest that the impact of the MC phases varies greatly among individuals. Individuals with high fluctuations in sex hormone concentrations may experience relevant changes in the assessed parameters. [ABSTRACT FROM AUTHOR]

Objectives: This study investigated the efficacy of wheat peptide supplementation compared to regular proteins in elite cross-country skiers, providing insights into the metabolic and performance effects of these supplements in order to guide athletes in selecting optimal energy sources for training and competition. Methods: Nineteen healthy male cross-country skiers were enrolled and assigned to either the peptide group (PEP, n = 9) or the protein group (PRO, n = 10). A four-week intervention study involving supplementation with wheat peptides/regular proteins was conducted, and pre- and post-intervention assessments were performed to evaluate exercise capacity and metabolic profiles. Results: The study found that the PEP group and the PRO group showed distinct within-group effects on exercise performance. The PEP group demonstrated improved aerobic capacity, including better performance in 10 km roller skating, an increased lactate threshold, and reduced resting blood lactate levels. The PRO group enhanced anaerobic capacity, such as improved sprint time, hexagon test performance, and lactate clearance. Metabolomic analysis revealed specific metabolic pathways affected in each group, with the PEP group showing impacts on the α-linolenic acid pathway and the PRO group on ketone body synthesis and degradation as well as vitamin B6 metabolism. Conclusions: Our findings indicate that wheat oligopeptides and regular proteins have comparable effects on exercise performance. However, the wheat peptides may offer greater advantages in enhancing aerobic capacity. No significant variations were observed in blood metabolite profiles between the two groups, but distinct metabolic pathways exhibited different responses. [ABSTRACT FROM AUTHOR]

This study aimed to determine changes in the kinematics of sprint steps based on progressive muscular fatigue during high-intensity 350-m and 500-m trials. Twelve elite healthy male 400-m sprinters with a minimum of six years of regular sprint training experience were recruited. They were divided into two groups for the experiment: a 350-m and a 500-m trial group. Time and kinematics of sprinting step motion for specific segments, i.e., starting to final stages of each trial, were obtained using the Opto Jump-Microgate optical measurement system. The starting phase of each sprint was defined as the section without muscular fatigue (noF), and the final phase was the sprint under muscular fatigue (onF). Each last 25 m of the 50-m evaluated section containing ten complete running steps was selected for detailed statistical analysis. Various patterns of temporal and spatial variables of sprinting efforts were observed between 350-m and 500-m trials. Each trial result was influenced by significant individual changes (p < 0.05). All variables indicated that the two distances differed significantly in terms of running kinematics. This was confirmed by significant differences in the mean step frequency (p < 0.001), which presented a difference of 11.75%, and the mean step speed (p < 0.001). As a result of these changes, a hierarchical intermittent endurance training pattern was defined. The research concluded that special endurance (intermittent sprints) based on 350 m differed significantly in kinematics from sprints over 500 m. Therefore, it should be assumed that the distance of 350 m is more similar in its kinematics to the 400-m competition. This should encourage coaches and athletes to apply a 350-m distance in training developing special endurance, especially in the pre-competitive and competitive periods. [ABSTRACT FROM AUTHOR]

During high-intensity (HI) exercise, metabolic acidosis significantly impairs exercise performance. Increasing the body's buffering capacity through training and exogenous intake of alkalizing supplements may improve highintensity performance. Manipulating water and diet intake may influence the acid-base balance. The aim of this study was to determine the effects of mineral water rich in bicarbonate ions (STY) or placebo water (PLA) on circulating biomarkers and anaerobic performance and to verify whether alkalizing (ALK) or acidizing (ACI) diet would modulate these effects. Twenty-four athletes, assigned either to ALK (n = 12) or ACI (n = 12) diet for four weeks, completed a 1-min rowing Wingate Test in a double-blind and randomized trial after one week of daily hydration (1.5 to 2L/d) with either STY or PLA. Blood samples were taken before and after each test, and urine samples were collected each week. Chronic consumption of bicarbonate-rich water significantly impacted resting urinary pH irrespective of alkalizing or acidizing dietary intake. STY induced a significant increase in blood pH, lactate, and HCO3- ion concentration postexercise compared to PLA. Similar changes were observed when STY was associated with the ALK diet. In contrast, STY combined with the ACI diet only significantly affected urine pH and peak blood lactate compared to PLA (p < 0.05). No effect of bicarbonate-rich water was reported on anaerobic performance (p > 0.05). Our results suggest that consumption of bicarbonate-rich water alters acid-base balance during a warm-up and after HI exercise, could potentiate beneficial effects of an alkalizing diet on the acid-base balance after HI exercise, and reduces the acid load induced by an acidifying diet. [ABSTRACT FROM AUTHOR]

Short-term fatigue protocols simulating sports participation are scarce and not well-documented in jumplanding sports. Therefore, this study investigated physiological and physical responses following high-intensity, intermittent exercise protocols (HIIPs) with a standardized level of subjective exhaustion (Borg ≥18/20) and a modified fixed version of five circuits (HIIP-5) for future inclusion in biomechanical screening protocols. Twenty male volleyball and basketball players participated in this study to complete the HIIP and the HIIP-5. Physiological and physical variables were assessed before and up to 30 min after cessation of both protocols. Regarding physiological variables, heart rate values increased (+104 bpm, p < 0.001) and remained elevated up to 30 min (+34 bpm, p < 0.001), and blood lactate levels increased (+17 mmol/l, p < 0.001) compared to baseline. Regarding physical variables, decreased jump height (-4 cm, p = 0.001-0.009) and quadriceps muscle strength (p = 0.001-0.050) were observed up to 30 min compared to baseline. The type of the fatigue protocol did not have an effect on the investigated variables (p > 0.05). To conclude, both the HIIP and the HIIP-5 seem valuable tools to induce acute and long-lasting responses, providing a sufficiently large time window of 30 min within which biomechanical markers of injury can be assessed under fatigued conditions in future risk factor screenings. In practice, the fatigue protocol can be terminated after only five circuits if athletes had not yet been stopped at that point due to exhaustion (Borg ≥18/20). [ABSTRACT FROM AUTHOR]

Background: Exposure to a hypobaric hypoxic environment at high altitudes can lead to lung injury. In this study, we aimed to determine whether curcumin (Cur) could improve lung barrier function and protect against high-altitude-associated acute lung injury. Methods: Two hundred healthy rats were randomly divided into standard control, high-altitude control (HC), salidroside (40 mg/kg, positive control), and Cur (200 mg/kg) groups. Each group was further divided into five subgroups. Basic vital signs, lung injury histopathology, routine blood parameters, plasma lactate level, and arterial blood gas indicators were evaluated. Protein and inflammatory factor (tumor necrosis factor α (TNF-α), interleukin [IL]-1β, IL-6, and IL-10) concentrations in bronchoalveolar lavage fluid (BALF) were determined using the bicinchoninic acid method and enzyme-linked immunosorbent assay, respectively. Inflammation-related and lung barrier function-related proteins were analyzed using immunoblotting. Results: Cur improved blood routine indicators such as hemoglobin and hematocrit and reduced the BALF protein content and TNF-α, IL-1β, and IL-6 levels compared with those in the HC group. It increased IL-10 levels and reduced pulmonary capillary congestion, alveolar hemorrhage, and the degree of pulmonary interstitial edema. It increased oxygen partial pressure, oxygen saturation, carbonic acid hydrogen radical, and base excess levels, and the expression of zonula occludens 1, occludin, claudin-4, and reduced carbon dioxide partial pressure, plasma lactic acid, and the expression of phospho-nuclear factor kappa. Conclusions: Exposure to a high-altitude environment for 48 h resulted in severe lung injury in rats. Cur improved lung barrier function and alleviated acute lung injury in rats at high altitudes. Highlights: • Curcumin (Cur) improves lung barrier function under high-altitude stress in rats • Cur mitigated acute lung injury under high-altitude stress • Cur improved hemoglobin and hematocrit levels under high-altitude stress • Cur reduced bronchoalveolar lavage fluid protein content under high-altitude stress • Cur reduced inflammatory factor TNF-α, IL-α, IL-6 levels under high-altitude stress [ABSTRACT FROM AUTHOR]

Recreational angling for novel marine species and related tourism development can be important in a Blue Economy. The milkfish (Chanos chanos) is growing in popularity as a target of fly fishing‐based catch‐and‐release (C&R) recreational fisheries, largely because of their challenge to catch and powerful swimming abilities, resulting in fight times that can exceed 1 h. Anecdotal sentiments by anglers claim that milkfish can fight for long periods of time because they do not accumulate blood lactate. To test this hypothesis, we measured blood lactate and blood glucose for 21 milkfish caught by fly fishing in the remote Alphonse Group of islands, Republic of Seychelles. Fight times ranged 5–78.3 min. Blood lactate and blood glucose concentrations increased with fight times that did not exceed 60 min. Total length of milkfish was not correlated to blood lactate or blood glucose concentrations. Ours is the first study on C&R of milkfish that debunks the anecdote that milkfish can fight for long periods of time because they do not accumulate blood lactate. Our study also revealed that milkfish may begin to physiologically recover after fight times longer than 60 min. In the context of C&R, our study indicates that anglers should limit fight times to 20–30 min when possible to reduce angling‐induced physiological stress and other potential impacts (e.g., depredation) on milkfish in recreational fisheries. [ABSTRACT FROM AUTHOR]

Machine perfused ex-vivo organs offer an excellent experimental platform, e.g., for studying organ physiology and for conducting pre-clinical trials for drug delivery. One main challenge in machine perfusion is the accurate assessment of organ condition. Assessment is often performed using viability markers, i.e., lactate concentrations and blood gas analysis. Nonetheless, existing markers for condition assessment can be inconclusive, and novel assessment methods remain of interest. Over the last decades, several imaging modalities have given unique insights into the assessment of organ condition. A systematic review was conducted according to accepted guidelines to evaluate these medical imaging methods, focussed on literature that use machine perfused human-sized organs, that determine organ condition with medical imaging. A total of 18 out of 1,465 studies were included that reported organ condition results in perfused hearts, kidneys, and livers, using both conventional viability markers and medical imaging. Laser speckle imaging, ultrasound, computed tomography, and magnetic resonance imaging were used to identify local ischemic regions and quantify intraorgan perfusion. A detailed investigation of metabolic activity was achieved using 31P magnetic resonance imaging and near-infrared spectroscopy. The current review shows that medical imaging is a powerful tool to assess organ condition. [ABSTRACT FROM AUTHOR]

Introduction: We assessed metabolic and hormonal responses to high-load resistance exercise under varying normobaric hypoxia conditions with a saturation clamp. Methods: Employing a counterbalanced, crossover test design, ten well-trained men participated in three exercise trials with normoxic or hypoxic gas mixtures to maintain arterial oxygen saturation at --90% and 80% [moderate (MH) and severe (SH) hypoxia, respectively]. The resistance exercise regimen comprised five sets of 10 repetitions of barbell back squats at 70% of one repetition maximum, with 1- min rest between sets. Metabolic and hormonal responses were measured before normoxia or hypoxia exposures (Pre 1), 15 min after the exposures (Pre 2), and at 0-, 15-, and 30-min post-exercises (T0, T15, and T30, respectively). Results: Compared to Pre 2, blood lactate concentrations and growth hormone values were elevated at T0, T15, and T30 (p ≤ 0.001), while testosterone values increased at T0 in all conditions (p ≤ 0.009). Epinephrine values increased significantly from Pre 2 to T0 in SH only (p < 0.001). SH had significantly higher blood lactate concentrations (p = 0.023), growth hormone (p = 0.050), and epinephrine (p = 0.020) values at T30 compared to NM. Cortisol values were elevated above Pre 2 at T15 in MH and SH, while lower testosterone values were noted at T0 and T15 for SH compared to NM and MH (all p ≤ 0.05). Discussion: Severe simulated hypoxia, achieved through a saturation clamp during barbell back squats, may enhance metabolic and hormonal responses, particularly 30 min post-session. Nevertheless, the acute effects of hypoxia exposure seem to be overridden by the impact of high-load resistance exercise. [ABSTRACT FROM AUTHOR]

Chronic nonspecific low back pain (CNLBP) is a leading cause of disability and remains a major burden for many public health systems. Acupuncture is a nonpharmacological treatment for CNLBP that can be effective in improving low back pain; nevertheless, its effect on improving back muscle endurance in patients with CNLBP and its duration of effect have not been studied. The goal of this study was to assess the impact of acupuncture on lower back muscle activity in CNLBP patients. This was a single-blind, randomized, crossover experimental study. Thirty female patients were randomized into Group A (15 patients) or Group B (15 patients). Patients in Group A were assigned to receive real acupuncture (RA) in the first phase and sham acupuncture (SA) in the second phase, while those in Group B received SA first and then RA, with a 1-week washout period between phases. Two-way repeated ANOVA was used to evaluate the effect of group and time on isokinetic parameters, Surface electromyography (sEMG) data, and blood data. Significant interaction effects were identified between group * time on the isokinetic parameters of the lumbar extensor muscles, sEMG values of the erector spinae, blood lactate levels, and blood ammonia levels (all p< 0.05). Compared with those of the SA group, the isokinetic parameters of the lumbar extensor muscles, sEMG values of the erector spinae, blood lactate levels, and blood ammonia levels of the RA group were significantly different (all p< 0.05). RA improves lumbar extensor endurance in patients with CNLBP and lasts approximately 9 minutes. RA can improve blood circulation to reduce blood lactic acid and blood ammonia produced during exercise. [ABSTRACT FROM AUTHOR]

Key points There is evidence that aerobic exercise improves brain health. Benefits may be modulated by acute physiological responses to exercise, but this has not been well characterized in older or cognitively impaired adults. The randomized controlled trial ‘AEROBIC’ (NCT04299308) enrolled 60 older adults who were cognitively healthy (n = 30) or cognitively impaired (n = 30) to characterize the acute brain responses to moderate [45–55% heart rate reserve (HRR)] and higher (65–75% HRR) intensity acute exercise. Each participant received two fluorodeoxyglucose positron emission tomography (FDG‐PET) scans, one at rest and one following acute exercise. Change in cerebral glucose metabolism from rest to exercise was the primary outcome. Blood biomarker responses were also characterized as secondary outcomes. Whole grey matter FDG‐PET standardized uptake value ratio (SUVR) differed between exercise (1.045 ± 0.082) and rest (0.985 ± 0.077) across subjects [Diff = −0.060, t(58) = 13.8, P < 0.001] regardless of diagnosis. Exercise increased lactate area under the curve (AUC) [F(1,56) = 161.99, P < 0.001] more in the higher intensity group [mean difference (MD) = 97.0 ± 50.8] than the moderate intensity group (MD = 40.3 ± 27.5; t = −5.252, P < 0.001). Change in lactate AUC and FDG‐PET SUVR correlated significantly (R2 = 0.179, P < 0.001). Acute exercise decreased whole grey matter cerebral glucose metabolism. This effect tracked with the systemic lactate response, suggesting that lactate may serve as a key brain fuel during exercise. Direct measurements of brain lactate metabolism in response to exercise are warranted. Acute exercise is associated with a drop in global brain glucose metabolism in both cognitively healthy older adults and those with Alzheimer's disease. Blood lactate levels increase following acute exercise. Change in brain metabolism tracks with blood lactate, suggesting it may be an important brain fuel. Acute exercise stimulates changes in brain‐derived neurotrophic factor and other blood biomarkers. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of whole-body cryotherapy (WBC) on acute recovery after a single high-intensity training day. Twelve elite professional male rowers from the national aquatic training base. They were randomly divided into a WBC group (n = 6) and a control group (CON group, n = 6). They performed a high-intensity training program, with a single session immediately followed by WBC (-110°C, 3 min) or recovered naturally for 3 min (CON group). Rowing performance, skin temperature, heart rate, blood pressure, and blood lactate concentrations were recorded before training, immediately, 5 min, and 15 min after the intervention. Blood samples were collected early in the morning of the day of intervention and that of the following day. The results indicated that 1) the blood lactate concentrations after WBC were significantly lower than pre-training (p < 0.05); 2) the maximum power significantly decreased immediately after WBC compared to pre-training (p < 0.05); 3) a significant main effect of time was observed for average speed, which significantly decreased after WBC (p < 0.05); 4) a significant main effect of time for blood parameters was observed. Specifically, hematocrit, cortisol, and hemoglobin were significantly lower after WBC than pre-intervention, whereas testosterone/cortisol was significantly higher than pre-intervention (p < 0.05). The results of this study showed that a single session of WBC had a positive effect on accelerating the elimination of blood lactate after HIT, but did not significantly change rowing performance and physiological parameters. A single session of WBC was not an effective strategy for elite rowers for acute recovery after HIT. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the effects of acute ingestion of saffron (SAF) on physiological (i.e., heart rate and blood lactate) and perceptual (i.e., ratings of perceived exertion [RPE] and feeling scale) measures in response to a repeated-sprint ability test (RSS) in healthy young males (N = 22; mean ± SD: age, 21.7 ± 1.24 yrs.). All participants completed two experimental trials with a one-week washout period using a double-blind, placebo-controlled, crossover design. In each session, the participants were randomly chosen to receive either a capsule of saffron (300 mg) (SAF session) or a capsule of lactose (PLB session) two hours before performing the RSS. No significant differences (p > 0.05) were found for heart rate, RPE, and feeling scale between the SAF or PLB sessions at pre- and post-RSS. There were no significant changes (p > 0.05) in peak time, total time, fatigue index, and blood lactate in either the SAF or PLB sessions. Acute SAF ingestion did not significantly improve RSS performance nor physiological and perceptual measures in active young males. Future trials should address the topic by using shortened/prolonged higher doses of SAF on biological, physical, physiological, and perceptual responses to acute and chronic exercise. [ABSTRACT FROM AUTHOR]

Scientists and coaches seek effective ergogenic aids for performance improvement. Cyclists commonly use β-Alanine, which may enhance post-exercise recovery and physical performance. High-dose β-Alanine supplementation's impact on World Tour cyclists during a 7-day camp remains unstudied. This study aimed to analyse the effect of a high dose of β-alanine in World Tour cyclist during a 7-day camp. A double-blinded, randomised controlled trial was conducted. 11 cyclists were included in the final analysis: β-alanine supplementation (n = 5; VO2max: 67.6±1.6 ml/kg/min) and a placebo group (n = 6; VO2max: 68.0±2.4 ml/kg/min). The duration of the supplementation protocol was seven days with four daily intakes. The subjects commenced supplementation after the physical tests (immediately following the snack) and consumed the final intake after breakfast on the day of the final test (a total of 7 days and 3 additional doses, 31 servings in total; 5g per dosage; 155g the total cumulative amount). Before and after seven days of supplementation, the cyclists performed an uphill time trial. Blood lactate, heart rate and rating of perceived exertion were measured during test. β-alanine supplementation improved the relative mean power attained during the time-trial compared with the control group (Z = -2.008; p = 0.045; Δ = 0.060), as well as the time needed to complete this trial (Z = -2.373; p = 0.018). As for physiological and metabolic variables, no significant change was found. In conclusion, the present study supports the effectiveness of one-week high dose of β-alanine during a cycling training in World Tour cyclists to improve their uphill time-trial performance. In addition, it is important to highlight the potential role of β-alanine in improving recovery power. This aspect is particularly relevant in the context of a training camp, where fatigue levels can increase alongside training intensity. Trial registration: This study was registered in ClinicalTrials.gov: (identifier: NCT04427319). [ABSTRACT FROM AUTHOR]

Bovine hemolytic anemia has a negative impact on animal welfare and productivity due to its associated clinical symptoms. Hemolysis is generally known to cause reticulocytosis, increased indirect bilirubin, decreased concentration of haptoglobin, and increased lactate dehydrogenase. Additionally, tissue hypoperfusion due to concomitant anemia increases blood lactate concentration. However, few studies have reported the correlation between these indicators and hemolytic anemia in cattle. We expected that alterations in hematological and biochemical parameters could identify cattle with hemolytic anemia. Therefore, in addition to reporting differences in indicators according to hemolytic anemia, this study aimed to derive indicators and set criteria for identification of bovine hemolytic anemia. In cattle with hemolytic anemia, reticulocytosis, increased indirect bilirubin, and increased L-lactate were observed, and the correlation of these indicators with hematocrit (HCT) was confirmed. And since HCT alone has limitations in identifying hemolytic anemia, we suggest additional criteria to identify hemolytic anemia in cattle. [ABSTRACT FROM AUTHOR]

Blood lactate concentration is an established circulating biomarker for measuring muscle acidity and can be evaluated for monitoring endurance, training routines, or athletic performance. Sweat is an alternative biofluid that may serve similar purposes and offers the advantage of noninvasive collection and continuous monitoring. The relationship between blood lactate and dynamic sweat biochemistry for wearable engineering applications in physiological fitness remains poorly defined. Here, we developed a microfluidic wearable band with an integrated colorimetric timer and biochemical assays that temporally captures sweat and measures pH and lactate concentration. A colorimetric silver nanoplasmonic assay was used to measure the concentration of lactate, and dye-conjugated SiO2 nanoparticle–agarose composite materials supported dynamic pH analysis. We evaluated these sweat biomarkers in relation to blood lactate in human participant studies during cycling exercise of varying intensity. Iontophoresis-generated sweat pH from regions of actively working muscles decreased with increasing heart rate during exercise and was negatively correlated with blood lactate concentration. In contrast, sweat pH from nonworking muscles did not correlate with blood lactate concentration. Changes in sweat pH and blood lactate were observed in participants who did not regularly exercise but not in individuals who regularly exercised, suggesting a relationship to physical fitness and supporting further development for noninvasive, biochemical fitness evaluations. Editor's summary: The makeup of our sweat has the potential to be used to noninvasively monitor health during exercise. Here, Cho et al. develop a wearable microfluidic band to measure local sweat biochemistry of muscles in human participants during rest or cycling exercise. The device incorporates a colorimetric "timer" that allows the collection of longitudinal sweat pH and lactate concentration measurements. Blood lactate concentration, a known circulating biomarker of muscle activity, was correlated with local sweat pH over actively working muscles. Therefore, changes in sweat pH during exercise may be an indicator of muscle fatigue. —Molly Ogle [ABSTRACT FROM AUTHOR]

In this work, we have studied the stability constants of ternary cobalt(II) complexes with the primary ligands: pyridine-2,3-dicarboxylic acid (H22,3-Dipic, H2L) and pyridine-3,4-dicarboxylic acid (H23,4-Dipic, H2L) and secondary ligands representing low molecular mass components of blood serum: lactic acid (HLac), oxalic acid (H2Ox), citric acid (H3Cit), and phosphoric acid (H3PO4). Potentiometric data were analyzed using the least squares computational program LETAGROP. Ionic strength and temperature were both kept constant using 1.0 mol dm−3 NaNO3 as ionic medium at 25 °C. Species distribution diagrams were generated to determine the speciation variations with respect to pH. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to examine the relationship between microcirculation and macrocirculation in the early period after extracorporeal circulation (ECC). Specifically, it investigates whether macrocirculation parameters such as Double Product (DP) and Shock Index (SI) can predict microcirculation by studying their correlation with lactate levels, a marker of microcirculation, in the early post-ECC period. Methods: The study analyzed the demographic, hemodynamic, and laboratory data of 2039 patients who underwent isolated coronary bypass surgery with ECC at Acıbadem Kadıköy and Acıbadem Altunizade Hospitals between 1999 and 2023. The data included serum lactate levels, DP, and SI measurements taken before induction and after ECC for all patients, as well as for the subgroup with DP values above 12,000. Results: The analysis did not find any correlation between plasma lactate levels and DP and SI during the post-ECC period; p=0.11, r=0.04 (-0.01; 0.08) and p<0.001, r=0.11 (0.06; 0.15), respectively. Similarly, no correlation was found between plasma lactate values and DP in patients with DP values >12,000 (n=284) (p=0.643, r=0.03 (-0.09; 0.14)). Conclusion: Vital parameters do not fully capture circulatory disorders. It would be more appropriate for critically ill patients to assess microcirculation using parameters such as lactate directly. Therefore, further studies are necessary to evaluate microcirculation and develop independent parameters. [ABSTRACT FROM AUTHOR]

Competitive collegiate dance combines elements of gymnastics and acrobatics with more traditional styles, such as ballet, jazz, and modern dance. Assessing the physiological demands and identifying clear measures of intensity and duration of such dance provide a framework for planning the competitive season and developing strength and conditioning programs. This study examined the blood lactate (BL), heart rate (HR), and ratings of perceived exertion (RPE) of 14 well-trained female dancers on a competitive collegiate dance team. Subjects completed a treadmill test to determine their lactate threshold (LT) and then performed a 120-second choreographed jazz dance routine in cumulative 30-second segments, during which physiological markers were measured. All subjects exceeded their individually determined LT values by 90 seconds into the dance routine. A moderate (rs = 0.53; p < 0.001) positive correlation was observed between HR and RPE, as was a strong (rs = 0.70; p < 0.001) positive correlation between BL and RPE. Subjects worked at or above LT for much of the 120-second jazz dance routine, indicating that competitive collegiate dance is physiologically demanding and highly anaerobic. Understanding the physiological demands of competitive collegiate dance allows strength and conditioning professionals to develop, monitor, and adjust training parameters, which will aid in minimizing injury and maximizing competitive performance in collegiate dancers. [ABSTRACT FROM AUTHOR]

Transmembrane prolyl 4-hydroxylase (P4H-TM) is an enigmatic enzyme whose cellular function and primary substrate remain to be identified. Its loss-of-function mutations cause a severe neurological HIDEA syndrome with hypotonia, intellectual disability, dysautonomia and hypoventilation. Previously, P4H-TM deficiency in mice was associated with reduced atherogenesis and lower serum triglyceride levels. Here, we characterized the glucose and lipid metabolism of P4h-tm−/− mice in physiological and tissue analyses. P4h-tm−/− mice showed variations in 24-h oscillations of energy expenditure, VO2 and VCO2 and locomotor activity compared to wild-type (WT) mice. Their rearing activity was reduced, and they showed significant muscle weakness and compromised coordination. Sedated P4h-tm−/− mice had better glucose tolerance, lower fasting insulin levels, higher fasting lactate levels and lower fasting free fatty acid levels compared to WT. These alterations were not present in conscious P4h-tm−/− mice. Fasted P4h-tm−/− mice presented with faster hepatic glycogenolysis. The respiratory rate of conscious P4h-tm−/− mice was significantly lower compared to the WT, the decrease being further exacerbated by sedation and associated with acidosis and a reduced ventilatory response to both hypoxia and hypercapnia. P4H-TM deficiency in mice is associated with alterations in whole-body energy metabolism, day-night rhythm of activity, glucose homeostasis and neuromuscular and respiratory functions. Although the underlying mechanism(s) are not yet fully understood, the phenotype appears to have neurological origins, controlled by brain and central nervous system circuits. The phenotype of P4h-tm−/− mice recapitulates some of the symptoms of HIDEA patients, making this mouse model a valuable tool to study and develop tailored therapies. [ABSTRACT FROM AUTHOR]

Purpose: Exogenous melatonin has been proven to have beneficial effects on sleep. A good sleep quality promotes recovery and improves physical performance. In this sense, the present study aimed to explore the potential effect of nocturnal melatonin ingestion on psycho-cognitive and short-term maximal performances, in the following morning. Method: Twelve professional soccer players (22.9 ± 1.3 years, 1.80 ± 0.05 m, and 72.0 ± 8.8 kg) volunteered to perform two separate testing sessions after either nocturnal melatonin or placebo ingestion. The next morning, participants performed the following psycho-cognitive and physical tests: Hooper's index, reaction time, vigilance, handgrip strength (HG), squat jump (SJ), modified agility T-test (MAT) and Wingate anaerobic test (WanT). Rating of perceived exertion (RPE) and blood lactate [La] were recorded, respectively, immediately and 3 min after the WanT. Blood glucose [GL] was measured before and 3 min after WanT. Results: Compared with placebo, melatonin improved subjective sleep quality, short-term maximal performances (HG and SJ), reaction-time, as well as peak and mean WanT powers and decreased fatigue index and RPE scores. However, [La] and [GL] were not affected by melatonin ingestion. Conclusion: Nocturnal melatonin intake before sleep has beneficial effects on cognitive and physical performances the following day. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study aimed to examine whether a period of high intensity intermittent training (HIIT) training influences aerobic and anaerobic performance in elite Karate athletes. Sixteen elite karate athletes volunteered to participate in this study. The athletes were randomly and gender-specifically divided into high intensity intermittent training (HIIT) group performed three times/week in addition to normal training for 6 weeks, and a traditional training (TT) group completing regular karate training. Body composition and maximal oxygen consumption as well as muscle power, speed, agility, and anaerobic power variables were assessed before and after the intervention. In addition, the blood lactate levels were measured in rest, after a warm-up period, and immediately, 5, 30, and 60 min after a Wingate test. The level of significance set ρ ≤ 0.05 for the study. A significant difference was observed in VO2max between HIIT and TT groups in post-test (p = 0.006). Furthermore, a significant difference observed between the muscle power (p = 0.001), speed (p = 0.013), agility (p = 0.004), peak power (PP) (p = 0.002), average power (AP) (p = 0.004), VO2max (p = 0.002), and level of the blood lactate concentration 60 min after Wingate test (p = 0.001) in HIIT group from pre- to post-test. A time × group interaction in muscle power (p = 0.001), speed (p = 0.021), and VO2max (p = 0.005) was observed. HIIT positively influences aerobic and anaerobic power in elite karate athletes compared to TT. [ABSTRACT FROM AUTHOR]

Blood lactate concentration during exercise is a reliable indicator of energy metabolism and endurance performance. Lactate is also present in sweat, and sweating plays an important role in thermoregulation, especially in hot conditions. Recently, wearable sensors have enabled the real-time and noninvasive measurement of sweat lactate concentration, potentially serving as an alternative indicator of blood lactate response. However, the evidence regarding the relationship between sweat and blood lactate responses during incremental exercise in hot conditions is lacking. In a randomized cross-over design, six highly trained male runners completed two incremental treadmill tests under normal (20°C/50%RH) or hot (30°C/50%RH) conditions. The tests include 3-min running stages and 1-min recovery, starting at 12 km/h and increasing by 1 km/h at each stage. Blood and sweat lactate concentrations were measured at each stage to determine blood and sweat lactate thresholds (LT). Blood lactate concentrations were higher under hot conditions (p < 0.01), but there was no difference in the response pattern or velocity at blood LT between conditions. Significant early increase (p < 0.01) in sweat lactate and low velocity at sweat LT (p < 0.05) were observed under hot conditions. A significant correlation between blood and sweat lactate concentrations was found under normal conditions (p < 0.001) but not under hot conditions, and no significant correlations were observed between the velocity at blood and sweat LT. In conclusion, sweat lactate concentration does not consistently reflect blood lactate concentration during incremental exercise. [ABSTRACT FROM AUTHOR]