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Abstract Background Despite the well-known health benefits of exercise, women’s participation in exercise is low worldwide. As women are at risk of developing various chronic diseases as they age, suggesting effective exercise methods that can maximize energy consumption is needed to prevent such conditions. Excess post-exercise oxygen consumption (EPOC) can maximize energy consumption. In this crossover, randomized controlled trial, we aimed to compare the EPOC for different exercise modalities including continuous exercise (CE), interval exercise (IE), and accumulated exercise (AE) that spent the homogenized energy expenditure during exercise in healthy women. Methods Forty-four participants (age, 36.09 ± 11.73 years) were recruited and randomly allocated to three groups. The intensity of each modality was set as follows: CE was performed for 30 min at 60% peak oxygen uptake (VO2peak). IE was performed once for 2 min at 80% VO2peak, followed by 3 min at 80% VO2peak, and 1 min at 40% VO2peak, for a total of six times over 26 min. AE was performed for 10 min with a 60% VO2peak and was measured thrice a day. Results During exercise, energy metabolism was higher for IE and CE than that for AE. However, this was reversed for AE during EPOC. Consequently, the greatest energy metabolism was shown for AE during total time (exercise and EPOC). Conclusions By encouraging regular exercises, AE can help maintain and improve body composition by increasing compliance with exercise participation, given its short exercise times, and by efficiently increasing energy consumption through the accumulation of EPOC. Trial registration Clinical number (KCT0007298), 18/05/2022, Institutional Review Board of Konkuk University (7001355-202201-E-160).

Abstract We investigated the influence of short‐ and long‐interval cycling exercise with blood flow restriction (BFR) on neuromuscular fatigue, shear stress and muscle oxygenation, potent stimuli to BFR‐training adaptations. During separate sessions, eight individuals performed short‐ (24 × 60 s/30 s; SI) or long‐interval (12 × 120 s/60 s; LI) trials on a cycle ergometer, matched for total work. One leg exercised with (BFR‐leg) and the other without (CTRL‐leg) BFR. Quadriceps fatigue was quantified using pre‐ to post‐interval changes in maximal voluntary contraction (MVC), potentiated twitch force (QT) and voluntary activation (VA). Shear rate was measured by Doppler ultrasound at cuff release post‐intervals. Vastus lateralis tissue oxygenation was measured by near‐infrared spectroscopy during exercise. Following the initial interval, significant (P

Background: Despite the well-known health benefits of exercise, women's participation in exercise is low worldwide. As women are at risk of developing various chronic diseases as they age, suggesting effective exercise methods that can maximize energy consumption is needed to prevent such conditions. Excess post-exercise oxygen consumption (EPOC) can maximize energy consumption. In this crossover, randomized controlled trial, we aimed to compare the EPOC for different exercise modalities including continuous exercise (CE), interval exercise (IE), and accumulated exercise (AE) that spent the homogenized energy expenditure during exercise in healthy women. Methods: Forty-four participants (age, 36.09 ± 11.73 years) were recruited and randomly allocated to three groups. The intensity of each modality was set as follows: CE was performed for 30 min at 60% peak oxygen uptake (VO2peak). IE was performed once for 2 min at 80% VO2peak, followed by 3 min at 80% VO2peak, and 1 min at 40% VO2peak, for a total of six times over 26 min. AE was performed for 10 min with a 60% VO2peak and was measured thrice a day. Results: During exercise, energy metabolism was higher for IE and CE than that for AE. However, this was reversed for AE during EPOC. Consequently, the greatest energy metabolism was shown for AE during total time (exercise and EPOC). Conclusions: By encouraging regular exercises, AE can help maintain and improve body composition by increasing compliance with exercise participation, given its short exercise times, and by efficiently increasing energy consumption through the accumulation of EPOC. Trial registration: Clinical number (KCT0007298), 18/05/2022, Institutional Review Board of Konkuk University (7001355-202201-E-160). [ABSTRACT FROM AUTHOR]

We investigated the influence of short‐ and long‐interval cycling exercise with blood flow restriction (BFR) on neuromuscular fatigue, shear stress and muscle oxygenation, potent stimuli to BFR‐training adaptations. During separate sessions, eight individuals performed short‐ (24 × 60 s/30 s; SI) or long‐interval (12 × 120 s/60 s; LI) trials on a cycle ergometer, matched for total work. One leg exercised with (BFR‐leg) and the other without (CTRL‐leg) BFR. Quadriceps fatigue was quantified using pre‐ to post‐interval changes in maximal voluntary contraction (MVC), potentiated twitch force (QT) and voluntary activation (VA). Shear rate was measured by Doppler ultrasound at cuff release post‐intervals. Vastus lateralis tissue oxygenation was measured by near‐infrared spectroscopy during exercise. Following the initial interval, significant (P < 0.05) declines in MVC and QT were found in both SI and LI, which were more pronounced in the BFR‐leg, and accounted for approximately two‐thirds of the total reduction at exercise termination. In the BFR‐leg, reductions in MVC (–28 ± 15%), QT (–42 ± 17%), and VA (–15 ± 17%) were maximal at exercise termination and persisted up to 8 min post‐exercise. Exercise‐induced muscle deoxygenation was greater (P < 0.001) in the BFR‐leg than CTRL‐leg and perceived pain was more in LI than SI (P < 0.014). Cuff release triggered a significant (P < 0.001) shear rate increase which was consistent across trials. Exercise‐induced neuromuscular fatigue in the BFR‐leg exceeded that in the CTRL‐leg and was predominantly of peripheral origin. BFR also resulted in diminished muscle oxygenation and elevated shear stress. Finally, short‐interval trials resulted in comparable neuromuscular and haemodynamic responses with reduced perceived pain compared to long‐intervals. What is the central question of this study?Does modifying exercise–rest durations during low‐intensity blood‐flow‐restricted (BFR) interval aerobic exercise modulate neuromuscular fatigue development, shear stress and muscle oxygenation?What is the main finding and its importance?BFR interval exercise resulted in significantly greater neuromuscular fatigue, predominantly of peripheral origin, compared to exercise with unrestricted blood flow. Furthermore, shorter BFR intervals elicited comparable neuromuscular and haemodynamic responses compared to longer intervals. These findings have important implications for developing optimized BFR training interventions and for future studies assessing whether these acute stimuli translate into enhanced physiological adaptations and subsequent improvements in performance. [ABSTRACT FROM AUTHOR]

Low-volume interval training has been demonstrated to improve indices of 24 h glycemic control using continuous glucose monitoring in individuals with or at risk for metabolic diseases. Nonetheless, there are inconsistencies in the literature with respect to the effects of interval exercise on 24 h glycemia, which may partly result from different nutritional conditions and/or controls adopted across various studies. This current opinion aims to provide a concise overview of the effects of acute and chronic interval exercise on 24 h glycemic control, while also describing how nutrition can influence and modify these responses. Given the distinct impact of dietary intake on blood glucose regulation, the adoption of diverse dietary control strategies during measurement of 24 h glycemia—spanning from using the participant's habitual diet to providing standardized meals customized to individual energy requirements—may contribute to varying conclusions across studies regarding the influence of interval exercise on 24 h glycemia. In addition, nutritional manipulations surrounding exercise, including whether interval exercise commences in the fasted or fed state, the macronutrient composition of post-exercise meals, and the presence of an energy and/or carbohydrate deficit among participants, offer important context when considering the effects of interval exercise on 24 h glycemia. Additional well-controlled studies are warranted to explore the interactive effects of interval exercise and nutrition on 24 h glycemia. These efforts will assist in refining exercise and nutrition recommendations aimed at improving glycemic control. [ABSTRACT FROM AUTHOR]

ABSTRACTBackground This study investigated the acute effects of various doses of nitrate-rich beetroot juice on the responses to high-intensity interval exercise in women.Methods A double-blinded, randomized, placebo-controlled, crossover trial was conducted with 13 recreationally active young women (age = 23 ± 2 years). All participants performed interval exercise (8 × 1-min bouts of cycling at 85% of peak power output [PPO] interspersed with 1-min active recovery at 20% of PPO) 2.5 h after consumption of the randomly assigned beetroot juice containing 0 mmol (placebo), 6.45 mmol (single-dose), or 12.9 mmol (double-dose) [Formula: see text]. The heart rate (HR), blood pressure, blood lactate, blood glucose, oxygen saturation, rating of perceived exertion (RPE), and emotional arousal were assessed.Results Nitrate supplementation significantly altered the HR and RPE responses across the three trials. The mean HR was lower in the single- and double-dose groups than in the placebo control group during both work intervals and recovery periods, as well as across the overall protocol (all p

Background: High‐intensity interval training (HIIT) is characterized by repeated bouts of relatively intense exercise interspersed with recovery periods. Previous studies have evaluated this exercise strategy with various population subgroups, regimens, and comparator groups, limiting the generalizability of findings. We performed a novel umbrella review to generate an up‐to‐date synthesis of the available evidence regarding the effect of HIIT on cardiorespiratory fitness (CRF) in adults as compared to non‐exercise control and traditional continuous forms of exercise such as moderate‐intensity continuous training (MICT). Methods: An umbrella review was conducted in accordance with the Preferred Reporting Items for Overviews of Reviews guideline. Seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) were searched until February 2024. Systematic reviews with meta‐analyses comparing HIIT and active/non‐active control conditions were included. Literature search, data extraction, and methodological quality assessment (AMSTAR‐2) were conducted independently by two reviewers. Results: Twenty‐four systematic reviews with meta‐analyses, representing 429 primary studies and 12 967 unique participants, met the inclusion criteria. Most of the systematic reviews received moderate‐to‐critically low AMSTAR‐2 scores. The data showed that HIIT, including the particularly intense variant "sprint interval training" (SIT), significantly increases CRF in adults compared to non‐exercise control (standardized mean difference [SMD]: 0.28 to 4.31; weighted mean difference [WMD]: 3.25 to 5.5 mL/kg/min) and MICT (SMD: 0.18 to 0.99; WMD: 0.52 to 3.76 mL/kg/min). This effect was consistently observed across specific groups of individuals (e.g., apparently healthy adults, individuals with overweight/obesity, older adults, and high‐level athletes) and HIIT modalities (e.g., low‐volume HIIT, whole‐body HIIT, home‐based HIIT, aquatic HIIT, and short SIT). Conclusion: Existing evidence from systematic reviews consistently supports the effect of HIIT on enhancing CRF in adults when compared to non‐exercise control and MICT. Our findings offer a comprehensive basis that may potentially contribute to informing physical activity guidelines aimed at improving CRF in the general population. [ABSTRACT FROM AUTHOR]

In the workplace, people are often sedentary for prolonged time and do not regularly engage in physical activity—two factors independently linked to premature morbidity and mortality. This study aimed to determine the receptivity of incorporating practical stair-climbing "exercise snacks" (Snacks; three isolated bouts of ascending 53–60 stairs performed sporadically throughout the day) into workplace settings compared to more traditional high-intensity interval training (HIIT; performed as three bouts of 53-60 stairs within a structured HIIT workout) and to explore if these exercise strategies could influence sedentary and physical activity behaviour. Fourteen participants (12 women; Mage = 38.9 ± 10.2 years) completed two supervised exercise trials (Snacks and HIIT) followed by 1 week participating in either form of exercise in their workplace. Ratings of perceived exertion (RPE), affective valence, enjoyment, and self-efficacy were measured at the supervised exercise sessions. During the follow-up period, sedentary behaviour and physical activity were measured with an accelerometer. Affective valence was more positive (p = 0.03; η2p = 0.21) and there was a lower rise in RPE (p = 0.01; η2p = 0.29) during Snacks than HIIT. Post-exercise enjoyment of, and self-efficacy towards, Snacks and HIIT were high and similar (ps > 0.05). After the supervised trials, 10/14 of the participants preferred Snacks and 4/14 preferred HIIT (p = 0.18). On days when participants chose to perform either exercise modality, the average number of sit-to-stands in a 24 h period was increased (48.3 ± 8.7 to 52.8 ± 7.8; p = 0.03; Hedge's g = 0.73) and moderate-to-vigorous physical activity tended to increase (21.9 ± 18.2 to 38.1 ± 22.1 min; p = 0.06; Hedge's g = 0.60) compared to days when they chose not to exercise. Stair-climbing exercise snacks may be an attractive approach to implement in the workplace setting and has potential to positively impact sedentary behaviour and physical activity metrics. [ABSTRACT FROM AUTHOR]

The objective of this research is to explore the influence of different exercise protocols on fat oxidation. Uncontrolled experimental study. For this purpose, 10 sedentary male subjects were recruited, 30 to 39 years old, with elevated body mass index (BMI). Each participant was evaluated in four separate sessions. The first session consisted in determining peak aerobic power (PAP). The following sessions participants performed three equivalent exercise protocols, consisting of each one in three bouts of 15-minute exercise separated by 5 minutes of rest in between. The constant intensity protocol included exercise periods at 55% of PAP, while the other two (increasing and decreasing intensity protocols) consisted in exercise periods at 40, 55 and 70% of PAP in an increasing or decreasing order respectively. There were no significant differences (P > 0.05) in total caloric expenditure among the three protocols (range: 5.9 ± 0.2 to 6.1 ± 0.2 kcal·kg−1). DIP causes a progressive increase in fat oxidation comparative to IIP and CIP protocols (P < 0.01). In period third of the protocols, DIP oxidized significantly more fat than the other two. The perception of effort was significantly lower in the DIP compared to the other two protocols (P < 0.01). Fat oxidation in exercises at intervals of different intensity depends on the order of these periods, being greater when performed decreasingly, as well as the perception of effort, being more useful for sedentary subjects with high BMI. [ABSTRACT FROM AUTHOR]

Background: Lifestyle modification is a newly recommended complementary treatment for dry eye (DE) disorder. Objective: To investigate the effect of a 6-month high-intensity interval aerobic exercise (HIIAE) (conducted 30 min, 3 times weekly) alone or combined with a caloric-restriction approach, the Mediterranean diet (MD), on DE parameters in obese hypertensive elderly. The design, settings, participants, and intervention: This is a randomized controlled trial included sixty obese hypertensive elderly with DE based on university-based hospital recruitment. Elderly were randomly assigned to the experimental group (n = 30 elderly received HIIAE plus MD) and control group (n = 30 elderly received only HIIAE). Besides anthropometry (abdominal circumference, body weight, and body mass index) and blood pressure (measured in systole and diastole), DE parameters (tear film break-up time, DE scoring system, ocular surface disability index questionnaire, Schirmer's test, and Oxford grading system) were evaluated. Results: Significant improvements in anthropometry, blood pressure, and DE parameters were higher in the experimental group than in the control group. Conclusion: Aging-related DE symptoms and signs can be prevented and/or treated with HIIAE alone or combined with MD in obese hypertensive elderly with DE disorder. [ABSTRACT FROM AUTHOR]

Copyright of Spor Hekimligi Dergisi/Turkish Journal of Sports Medicine is the property of Turkish Journal of Sports Medicine / Spor Hekimleri Dernegi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Interval training (IT) has been shown to be a time-effective alternative to traditional training programmes in the management of obesity. Nevertheless, studies comparing the effects of different IT intensities on inflammation, muscle and liver damage, and perceptual responses in people with obesity are relatively scarce. This study aimed to compare the acute effects of two different IT protocols matched by the mean load and duration on biochemical and perceptual responses in sedentary adults with obesity. Twenty-two volunteers (age = 33.40 ± 10.01 years, BMI = 38.29 ± 7.09 kg/m²) were randomized to perform two conditions: moderate-intensity IT (MIIT) 5 x 3 min (70% of peak power output (PPO))/2 min (45%PPO) and high-intensity IT (HIIT) 8 x 1 min (90%PPO)/2 min (45%PPO). Blood samples were drawn before and after exercise for biochemical and haematological measurements. Rating of perceived exertion (RPE) was assessed during and after exercise. Perceptual pain was evaluated before, throughout and after exercise. C-reactive protein, white blood cells and neutrophils increased only after HIIT (p < 0.001, for all). Aspartate aminotransferase, alanine aminotransferase, creatine kinase and lactate dehydrogenase increased in both HIIT and MIIT (p < 0.001, for all), without any difference between sessions. HIIT induced a greater increase of blood lactate compared to MIIT (p < 0.05). Pain and RPE scores were higher during HIIT vs. MIIT (p < 0.001 and p < 0.01, respectively). MIIT induced fewer immune system perturbations and less muscle pain and was perceived as more tolerable compared to HIIT session. Therefore, MIIT could be used as a first step to promote body adaptations before starting a HIIT programme in sedentary people with obesity. [ABSTRACT FROM AUTHOR]

Interval training (IT) has been shown to be a time-effective alternative to traditional training programmes in the management of obesity. Nevertheless, studies comparing the effects of different IT intensities on inflammation, muscle and liver damage, and perceptual responses in people with obesity are relatively scarce. This study aimed to compare the acute effects of two different IT protocols matched by the mean load and duration on biochemical and perceptual responses in sedentary adults with obesity. Twenty-two volunteers (age = 33.40±10.01 years, BMI = 38.29±7.09 kg/m²) were randomized to perform two conditions: moderate intensity IT (MIIT) 5×3 min (70% of peak power output (PPO))/2 min (45%PPO) and high-intensity IT (HIIT) 8×1 min (90%PPO)/2 min (45%PPO). Blood samples were drawn before and after exercise for biochemical and haematological measurements. Rating of perceived exertion (RPE) was assessed during and after exercise. Perceptual pain was evaluated before, throughout and after exercise. C-reactive protein, white blood cells and neutrophils increased only after HIIT (p < 0.001, for all). Aspartate aminotransferase, alanine aminotransferase, creatine kinase and lactate dehydrogenase increased in both HIIT and MIIT (p < 0.001, for all), without any difference between sessions. HIIT induced a greater increase of blood lactate compared to MIIT (p < 0.05). Pain and RPE scores were higher during HIIT vs. MIIT (p < 0.001 and p < 0.01, respectively). MIIT induced fewer immune system perturbations and less muscle pain and was perceived as more tolerable compared to HIIT session. Therefore, MIIT could be used as a first step to promote body adaptations before starting a HIIT programme in sedentary people with obesity.

Aiming the prevention and treatment of hypertension, regular physical exercise has become important to reduce blood pressure. The present experiment compared the effect of interval step exercise with continuous walking exercise on cardiovascular parameters of post-menopausal hypertensive women. The volunteers were submitted to three experimental sessions: control (CO), interval exercise (IE) and continuous exercise (CE), in randomized order. The sessions lasted 120 min and during this period, resting blood pressure was evaluated after 10min of siting rest before exercise, and 30, 40 and 60min of siting rest position after exercise. Heart rate variability (HRV) were estimated at rest before exercise and 30min after exercise. Blood pressure reactivity (BPR) to the Stroop Color-Word test was measured at rest before exercise and 60min after exercise. Twelve women finished the study (59 ± 4 years and BMI of 29.78 ± 4.10 kg/m2). The One way ANOVA showed that systolic blood pressure (SBP) area under the curve over time were lower (p = 0.014) in both exercise sessions comparing with control session. The Generalized estimation equations (GEE) showed that SDNN and RMSSD indices of HRV decreases (p < 0.001) in both exercises session as well, comparing with CO. Maximal SBP during Stroop test were lower after both IE and CE exercises session comparing with CO session. We conclude that interval step exercise can reduce blood pressure responses and improve HRV acutely after its performance and these responses are similar to continuous walking exercise. [ABSTRACT FROM AUTHOR]

Introduction: β-aminoisobutyric acid (BAIBA) is a suggested cytokine secreted from skeletal muscles that regulates insulin sensitivity, pancreatic function, and fat oxidation. However, no studies to date have examined if a low-calorie diet (LCD) or LCD + with interval exercise (LCD + INT) differentially raises BAIBA. The purpose was to examine if LCD or LCD + INT raises circulating BAIBA in relation to cardiometabolic health. Methods: For this, twenty-three women with obesity were randomized to either 2-weeks of LCD (n = 12, 48.4 ± 2.5 y, 37.84 ± 1.5 kg/m²; ~1200 kcal/day) or LCD + INT (n = 11, 47.6 ± 4.3 y, 37.9 ± 2.3 kg/m²; ~60 min/d of INT alternating 3 min of 90% and 50% HRpeak), with matched energy availability. Fasting BAIBA and adipokines along with glucose, insulin, C-peptide, and FFA after every 30 min up to 120 min were obtained during a 75 g OGTT to estimate total area under the curve (tAUC), insulin sensitivity (SIIS), pancreatic function [disposition index (DI)], and hepatic insulin clearance (HIC). Fuel use (indirect calorimetry) was tested at 0, 60, and 120 min of the OGTT along with fitness (VO2peak) and body composition (BodPod). Results: Both treatments lowered body weight (p < 0.001) and leptin (p < 0.001) but raised BAIBA (p = 0.007) and insulin sensitivity (p = 0.02). LCD + INT increased VO2peak (p = 0.02) and REE tAUC120min (p = 0.02) while LCD and LCD + INT decreased carbohydrate oxidation (CHOox) tAUC120min (p < 0.001). Increased BAIBA associated with reduced weight (r = -0.67, p < 0.001), leptin (r = -0.66, p = 0.001), CHOox tAUC120min (r = -0.44, p = 0.03) and DImuscle120min (r = -0.45, p = 0.03), but elevated HIC120min (r = 0.47, p = 0.02). Discussion: Concluding, LCD and LCD + INT increased BAIBA in relation to reduced body weight and pancreatic function in women with obesity. This suggests energy deficit is a key factor regulating circulating BAIBA. [ABSTRACT FROM AUTHOR]

Abstract Background High-intensity interval training (HIIT) has been promoted as a time-efficient exercise strategy to improve health and fitness in children and adolescents. However, there remains little consensus in the literature regarding its efficacy in children and adolescents with special educational needs (SEN). This study aimed to examine HIIT as a means of improving key health and fitness parameters in children and adolescents with SEN. Methods A systematic search was conducted on eight databases (MEDLINE, Embase, SPORTDiscus, Web of Science, Scopus, PsycINFO, CINAHL, and Cochrane Library). Studies were eligible if they 1) included an HIIT protocol, 2) examined parameters related to both physical and mental aspects of health and fitness, and 3) examined children and adolescents with SEN aged 5–17 years. Results Of the 1727 studies yielded by the database search, 13 (453 participants) were included and reviewed. We found that HIIT generally improved body composition, physical fitness, and cardiometabolic risk biomarkers across a spectrum of SEN (e.g., attention deficit hyperactivity disorder, cerebral palsy, developmental coordination disorder, and mental illness). Improvements in mental health and cognitive performance following HIIT have also been observed. Conclusion This review provides up-to-date evidence for HIIT as a viable exercise strategy for children and adolescents with SEN. Further research investigating the benefits of HIIT in a wider range of SEN populations is warranted. Trial registration This study was registered in the International Prospective Register of Systematic Review (PROSPERO; registration number CRD42022352696).

Exercise is commonly perceived as a pleasurable and healthy activity. However, it is classified as a complex activity that potentially enhances the formation of free radicals and oxidative stress. This study aims to analyze lipid peroxidation, as the biomarker of free radicals, in interval exercise. A total of 16 trained non-athlete male adolescents, aged 20-21 years old, with normal blood pressure, normal resting heart rate, and gave good level of physical fitness voluntarily participated in this study. The participants were randomly separated into two groups, namely the K1 (n=8, interval exercise with active resting medium intensity pedaling ergometer bike) and K2 (n=8, interval exercise with resting without pedaling the ergometer bike). The interval exercise was carried out at 60-70% HRmax intensity for 35 minutes. The blood sample for Malondialdehyde (MDA) level analysis, as the lipid peroxidation biomarker, was taken using Thiobarbituric acid reactive substances (TBARS). The blood samples were collected before and after the interval exercise. The obtained data were analyzed using the one-way ANOVA test with a 5% significance level. Our results suggest no significant different level of MDA, a lipid peroxidation biomarker, between the interval exercise with resting through medium intensity pedaling ergometer bike and the interval exercise with resting with no pedaling ergometer bike. However, the interval exercise resting through pedaling an ergometer bike presented relatively higher lipid peroxidation than the interval exercise resting without pedaling an ergometer bike. Therefore, following the free radical concept, interval exercise with resting through pedaling an ergometer bike is more beneficial than the exercise without pedaling an ergometer bike resting.

To explore the effects of essential amino acid (EAA) supplementation on high-intensity interval training (HIIT) fatigue, perceived exertion, and training progression in overweight and obese adults. A secondary aim was to explore potential sex-differences on these outcomes. Thirty-seven untrained adults (51% female; 36.2 ± 5.9 yrs; 35.5 ± 6.7% body fat) completed eight weeks of HIIT, 2d/wk on a cycle ergometer, either with EAA supplementation (HIIT + EAA; 3.6 g of EAA twice daily, 30 minutes pre and post HIIT) or without supplementation (HIIT). Heart rate (HR) and ratings of perceived exertion (RPE) were recorded throughout each session as indices of within training fatigue. Time to exhaustion (TTE) was recorded for the final interval of each session. Workload progression was determined by change in watts. Differences between groups (with and without EAA) were evaluated at 1wk, 4wks, and 8wks by repeated measure ANOVAs (α = 0.05). There were no differences in TTE (p = 0.983) or workload progression (p = 0.655) with EAA supplementation at any time point. HR and RPE within HIIT sessions were not significantly different with EAA supplementation at any time point (p > 0.05). Results were similar when evaluating males and females separately, but in females, RPE was significantly lower with EAA supplementation at 4wks (Δ: 1.1-2.2; p = 0.016). EAA supplementation did not extend TTE during exercise or enhance workload progression across eight weeks of HIIT in untrained, overweight and obese adults. However, EAA consumed 30 minutes before exercise may reduce perceived exertion during the first four weeks of training in women, which may have implications for overall exercise enjoyment and long-term adherence. [ABSTRACT FROM AUTHOR]

Background & Aims: Aging indicates physiological and biological changes in humans that are associated with a decrease in physical strength and cause changes in the anatomy and physiology of the body. It has been reported that at a rate of one percent per year, muscle mass decreases from the age of 30 to 60 and increases from the age of 60 onwards. The incidence of diseases such as type 2 diabetes, metabolic syndrome and cardiovascular disease, as well as chronic diseases of the musculoskeletal system and cancer are increasing, all of which can be affected by a decrease in muscle mass (1). Autophagic activity has been shown to decrease with age and may contribute to the accumulation of damaged macromolecules and organs during aging. Failure in the autophagy process exacerbates age-related diseases such as nerve damage or cancer (5). p62, a classical autophagy receptor, is a multifunctional protein located throughout the cell and involved in many signal transduction pathways, including the Keap1-Nrf2 pathway (7). p62 is an autophagy substrate used to report autophagic activity. Recently, p62 has been shown to deliver ubiquitinated proteins, including tau, to the proteasome for degradation. In addition, it can be a shuttle between the nucleus and the cytoplasm to facilitate and control the quality of cytosolic proteins (6). It has been well established that regular exercise improves physical function and brings important health benefits that inhibit many pathological diseases such as cancer as well as cardiovascular, metabolic and neurodegenerative diseases (8). Exercise promotes phenotypic adaptation in skeletal muscle, which includes mitochondrial biogenesis, angiogenesis, fiber deformation, and improved insulin sensitivity (9, 10). Regarding the effect of exercise on changes in autophagy, it has been reported that aerobic and resistance training leads to changes in autophagy indices (11, 12). Atroastetin is a type of statin that has a reducing effect on cholesterol production, as well as antioxidant, anti-inflammatory, anti-apoptotic and tissue protective effects in some pathological conditions (15-17). Study of mechanisms affecting the process of autophagy following exercise, including continuous and intermittent exercise with atroastetin supplementation can improve this process (22). Therefore, the aim of this study was to investigate the effect of eight continuous and interval exercises with atroastetin supplementation on mRNA p62 expression in elderly rats with type 2 diabetes. Methods: This is a semi-experimental study. 63 old male Wistar rats (mean weight 300 to 350 g) categorized into eight groups that included; 1) healthy control group, 2) diabetic control group, 3) diabetic group + continuous exercise, 4) diabetic group + interval exercise, 5) diabetic group + supplement, 6) diabetic group + continuous exercise + supplement, 7) diabetic group + interval exercise + supplement, and 8) saline group. Diabetes was induced by injection of 50 mg/kg streptozotocin. continuous and interval exercise program was performed, which included running at a speed of 15 to 29 meters per minute for 5 to 22 minutes for continuous aerobic exercise and six 2.5-minute sets with four minutes of rest between each set for interval exercise. Atherostatin supplementation with dose of 20 mg per kg body weight was injected intraperitoneally daily. One-way ANOVA was used for comparison between groups at the p <0.05. Results: The results showed that P62 mRNA expression was significantly reduced in all groups compared to the healthy and diabetic control group (p<0.001), but there was no significant difference between the other groups (p<0.05). (fig. 1). Conclusion: The results of the present study showed that despite the decrease in P62 mRNA expression in the experimental groups compared to the control and patient groups, no significant difference was observed between the other experimental groups. It seems that taking atroastetin supplementation, despite its anti-inflammatory and anti-oxidant effect, has no effect on the process of autophagy, which can be due to the amount used during the training period or the short-term use of atherostatin. Exercise has been reported to induce autophagy in skeletal muscle. Key autophagy proteins, including p62 and LC3-II, change significantly after exercise. These changes are consistent with an increase in autophagy after exercise. Tarawan et al. (2019) reported that exercise significantly reduced P62 in the muscles, which is more pronounced at moderate intensities. The researchers argued that at moderate intensities relative to high and low intensities, autophagic activity decreased after exercise and recommended moderate-intensity exercise (25). Exercise by phosphorylating Akt can inactivate the autophagy pathway through the PI3K-Akt-MTOR mediated pathway. Due to its unique properties, muscle fibers seem to play a significant role in the activity of autophagy and proteins involved in this process (26). Mejías et al. In the study showed that eight weeks of aerobic and resistance training in elderly men and women significantly increased LC3II / I, Atg16-12 and Bcl-2, but p62 expression decreased significantly (11, 12). Therefore, it is thought that exercise play a decisive role in inhibiting autophagy. Jamart et al. (2013) concluded that low-intensity exercise after fasting increases the activity of autophagy in skeletal muscle, which is due to a decrease in Akt pathway activity compared to satiety (27). The results of the present study showed that compared to the control and disease groups, P62 mRNA expression was significantly reduced; However, this decrease was not significant between the training groups and the training groups with supplementation. These results appear to be influenced by research methodology that the duration of the training period was insufficient or that the dose of atroastetin was low. continuous and interval exercise with atroastetin supplementation with anti-inflammatory and anti-oxidant effects on muscle cells is thought to reduce autophagy activity, resulting in a significant decrease in P62 mRNA expression compared with the patient group. In fact, exercise reduces the onset of autophagy in the skeletal muscle of diabetic rats by improving the antioxidant system and reducing the release of cytochrome c. However, the amount of reactive oxygen species has been reported to be high in animal and human species with type 2 diabetes (28). Therefore, continuous and interval exercise with atroastetin supplementation has been able to reduce autophagy markers, including P62 mRNA. There were some limitations in the present study, such as the lack of measurement of other autophagic indices such as LC3-II. It can also be noted that PI3K-Akt- MTOR autophagy pathway indices are not measured. Therefore, a study measuring these indicators in elderly samples with type 2 diabetes is recommended. According to the results, it seems that continuous and interval exercise with atherostatin supplementation can reduce P62 mRNA in elderly type 2 diabetic rats. [ABSTRACT FROM AUTHOR]

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Trimethylamine N-oxide (TMAO) is linked to cardiovascular disease (CVD) through partly altered central hemodynamics. We sought to examine if a low-calorie diet plus interval exercise (LCD+INT) intervention reduces TMAO more than a low-calorie diet (LCD) program alone in relation to hemodynamics, prior to clinically meaningful weight loss. Women with obesity were randomized to 2 weeks of LCD (n = 12, ~1200 kcal/d) or LCD+INT (n = 11; 60 min/d, 3 min at 90% and 50% HRpeak, respectively). A 180 min 75 g OGTT was performed to assess fasting TMAO and precursors (carnitine, choline, betaine, and trimethylamine (TMA)) as well as insulin sensitivity. Pulse wave analysis (applanation tonometry) including augmentation index (AIx75), pulse pressure amplification (PPA), forward (Pf) and backward pressure (Pb) waveforms, and reflection magnitude (RM) at 0, 60, 120, and 180 min was also analyzed. LCD and LCD+INT comparably reduced weight (p < 0.01), fasting glucose (p = 0.05), insulin tAUC180min (p < 0.01), choline (p < 0.01), and Pf (p = 0.04). Only LCD+INT increased VO2peak (p = 0.03). Despite no overall treatment effect, a high baseline TMAO was associated with decreased TMAO (r = −0.45, p = 0.03). Reduced TMAO was related to increased fasting PPA (r = −0.48, p = 0.03). Lowered TMA and carnitine correlated with higher fasting RM (r = −0.64 and r = −0.59, both p < 0.01) and reduced 120 min Pf (both, r = 0.68, p < 0.01). Overall, treatments did not lower TMAO. Yet, people with high TMAO pre-treatment reduced TMAO after LCD, with and without INT, in relation to aortic waveforms. [ABSTRACT FROM AUTHOR]

Background: Evidence has shown that when overweight/obese individuals are permitted to self-pace their exercise intensity during a continuous exercise, it tends to generate a greater positive affective response (pleasurable) compared to the prescribed-based exercise, but these have yet to be explored in the context of highintensity interval exercise (HIIE) in overweight and obese adults. We examined the health parameters (body composition, aerobic capacity, blood glucose, total cholesterol, triglyceride, HDL, and LDL) and perceptual responses (affective, enjoyment and perceived exertion) during prescribed HIIE (P-HIIE) and self-paced HIIE (S-HIIE) across a 5-week exercise intervention in overweight and obese adults. Methods: Twenty inactive men and women (mean ± SD; aged 26.7 ± 4.9 years old; BMI = 27.5 ± 4.2; PA levels = 482 ± 333 MET-min/week) were randomized to 5 weeks of P-HIIE (n=10; 6-8 ×1-min work-intervals at 90% of maximal aerobic speed) or S-HIIE (n=10; 6-8 ×1-min work-intervals at self-paced intensity), both for three days in a week (15 sessions in total). Perceptual responses observed in session 1, session 8, and session 15 were analyzed. Whereas health parameters were measured before and after 5 weeks exercise intervention. Results: P-HIIE group elicited lower affective responses across all work interval compared to S-HIIE group in session 1 (all P< 0.03, all ES> 0.66). Both groups generated greater post-enjoyment in session 8 and session 15 compared to session 1 (all P< 0.02, all ES> 0.60). Also, both P-HIIE and S-HIIE groups produced an enhancement in aerobic capacity (P<0.01, ES>0.71), but no significant between-group differences in the change of the pre- and post-measures of health markers. Conclusion: S-HIIE and P-HIIE protocols produce a comparable effect of perceptual responses and aerobic capacity over a 5-week exercise intervention in the overweight and obese cohort, indicating the viability and adoption of this protocol for health promotion in overweight and obese adults. [ABSTRACT FROM AUTHOR]

Introduction: β-aminoisobutyric acid (BAIBA) is a suggested cytokine secreted from skeletal muscles that regulates insulin sensitivity, pancreatic function, and fat oxidation. However, no studies to date have examined if a low-calorie diet (LCD) or LCD + with interval exercise (LCD + INT) differentially raises BAIBA. The purpose was to examine if LCD or LCD + INT raises circulating BAIBA in relation to cardiometabolic health.Methods: For this, twenty-three women with obesity were randomized to either 2-weeks of LCD (n = 12, 48.4 ± 2.5 y, 37.84 ± 1.5 kg/m2; ∼1200 kcal/day) or LCD + INT (n = 11, 47.6 ± 4.3 y, 37.9 ± 2.3 kg/m2; ∼60 min/d of INT alternating 3 min of 90% and 50% HRpeak), with matched energy availability. Fasting BAIBA and adipokines along with glucose, insulin, C-peptide, and FFA after every 30 min up to 120 min were obtained during a 75 g OGTT to estimate total area under the curve (tAUC), insulin sensitivity (SIIS), pancreatic function [disposition index (DI)], and hepatic insulin clearance (HIC). Fuel use (indirect calorimetry) was tested at 0, 60, and 120 min of the OGTT along with fitness (VO2peak) and body composition (BodPod).Results: Both treatments lowered body weight (p < 0.001) and leptin (p < 0.001) but raised BAIBA (p = 0.007) and insulin sensitivity (p = 0.02). LCD + INT increased VO2peak (p = 0.02) and REE tAUC120min (p = 0.02) while LCD and LCD + INT decreased carbohydrate oxidation (CHOox) tAUC120min (p < 0.001). Increased BAIBA associated with reduced weight (r = −0.67, p < 0.001), leptin (r = −0.66, p = 0.001), CHOox tAUC120min (r = −0.44, p = 0.03) and DImuscle120min (r = −0.45, p = 0.03), but elevated HIC120min (r = 0.47, p = 0.02).Discussion: Concluding, LCD and LCD + INT increased BAIBA in relation to reduced body weight and pancreatic function in women with obesity. This suggests energy deficit is a key factor regulating circulating BAIBA.

Background: High-intensity interval training (HIIT) has been promoted as a time-efficient exercise strategy to improve health and fitness in children and adolescents. However, there remains little consensus in the literature regarding its efficacy in children and adolescents with special educational needs (SEN). This study aimed to examine HIIT as a means of improving key health and fitness parameters in children and adolescents with SEN. Methods: A systematic search was conducted on eight databases (MEDLINE, Embase, SPORTDiscus, Web of Science, Scopus, PsycINFO, CINAHL, and Cochrane Library). Studies were eligible if they 1) included an HIIT protocol, 2) examined parameters related to both physical and mental aspects of health and fitness, and 3) examined children and adolescents with SEN aged 5–17 years. Results: Of the 1727 studies yielded by the database search, 13 (453 participants) were included and reviewed. We found that HIIT generally improved body composition, physical fitness, and cardiometabolic risk biomarkers across a spectrum of SEN (e.g., attention deficit hyperactivity disorder, cerebral palsy, developmental coordination disorder, and mental illness). Improvements in mental health and cognitive performance following HIIT have also been observed. Conclusion: This review provides up-to-date evidence for HIIT as a viable exercise strategy for children and adolescents with SEN. Further research investigating the benefits of HIIT in a wider range of SEN populations is warranted. Trial registration: This study was registered in the International Prospective Register of Systematic Review (PROSPERO; registration number CRD42022352696). [ABSTRACT FROM AUTHOR]

Abstract Background Performing multiple high-intensity interval training (HIIT) sessions in a compressed period of time (approximately 7–14 days) is called a HIIT shock microcycle (SM) and promises a rapid increase in endurance performance. However, the efficacy of HIIT-SM, as well as knowledge about optimal training volumes during a SM in the endurance-trained population have not been adequately investigated. This study aims to examine the effects of two different types of HIIT-SM (with or without additional low-intensity training (LIT)) compared to a control group (CG) on key endurance performance variables. Moreover, participants are closely monitored for stress, fatigue, recovery, and sleep before, during and after the intervention using innovative biomarkers, questionnaires, and wearable devices. Methods This is a study protocol of a randomized controlled trial that includes the results of a pilot participant. Thirty-six endurance trained athletes will be recruited and randomly assigned to either a HIIT-SM (HSM) group, HIIT-SM with additional LIT (HSM + LIT) group or a CG. All participants will be monitored before (9 days), during (7 days), and after (14 days) a 7-day intervention, for a total of 30 days. Participants in both intervention groups will complete 10 HIIT sessions over 7 consecutive days, with an additional 30 min of LIT in the HSM + LIT group. HIIT sessions consist of aerobic HIIT, i.e., 5 × 4 min at 90–95% of maximal heart rate interspersed by recovery periods of 2.5 min. To determine the effects of the intervention, physiological exercise testing, and a 5 km time trial will be conducted before and after the intervention. Results The feasibility study indicates good adherence and performance improvement of the pilot participant. Load monitoring tools, i.e., biomarkers and questionnaires showed increased values during the intervention period, indicating sensitive variables. Conclusion This study will be the first to examine the effects of different total training volumes of HIIT-SM, especially the combination of LIT and HIIT in the HSM + LIT group. In addition, different assessments to monitor the athletes' load during such an exhaustive training period will allow the identification of load monitoring tools such as innovative biomarkers, questionnaires, and wearable technology. Trial Registration: clinicaltrials.gov, NCT05067426. Registered 05 October 2021—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05067426 . Protocol Version Issue date: 1 Dec 2021. Original protocol. Authors: TLS, NH.

Purpose: Due to the intervals' nature of soccer, the aim of this study was to evaluate intermittent protocol of incremental laboratory test in measuring the physiological parameters of soccer players.Methods: Eighteen young soccer players (Mean ± SD; age 16.78 ± 0.78 years, weight 61.33 ± 9.44 kg, height 177 ± 6.75 Cm) voluntarily participated into two incremental laboratory tests (continuous and intermittent protocol) on the HP Cosmos Treadmill with 48-hour interval and then Bangesbo field test was performed. The subjects' cardiopulmonary parameters were measured by gas analyzer, metalyzer3b model, and blood lactate before and after the tests with lactometer Scout model. Statistical analysis was performed by ANOVA Repeated Measure, paired t-test and Pearson correlation coefficient at the significant level P ≤ 0.05.Results: There was no significant difference between the physiological factors of continuous and intermittent tests, but there was a significant difference between the distance at continuous and intermittent tests (P = 0.031). There was a significant positive relationship between the performance of the Bangesbo test with the maximum oxygen consumption (r = 0.64, P= 0.011) and distance (r = 0.62, P = 0.018) of the intermittent test.Conclusion: The significant positive correlation between the maximum oxygen consumption of the intermittent test and the performance of the Bangesbo test, Higher distance in intermittent test and significant positive correlation between performance of Bangesbo test and distance of intermittent incremental test; It may be explained by the similarity of the intermittent test to the interval component of the playing soccer and this observing suggest to consider component of athlete's activity when defining the incremental test.

Background/Objectives: High-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) alone has been shown to improve metabolic health, but the effects of alternating the two training approaches as often practiced in real life remained unclear. The purpose of the current study was to examine the effects of HIIT or MICT alone or alternating HIIT-MICT on cardiometabolic responses in inactive obese middle-aged men. Methods: Forty-two participants (age: 42 ± 5 y; BMI: 26.3 ± 2.1 kg m−2) were randomly assigned to four groups: HIIT (12 x 1-min running bouts at 80–90% HRmax interspersed with 1-min active recovery at 50% HRmax), MICT (40-min brisk walk at 65–70% HRmax), alternating HIIT-MICT or a non-exercise control group (CON). Exercise sessions were conducted three times per week for 16 weeks. Maximal oxygen uptake (VO2max), body composition (by bioelectrical impedance analysis), blood pressure, fasting blood glucose, insulin resistance (HOMA-IR) and lipid profile were assessed at baseline and after the 16-week intervention. Enjoyment and self-efficacy were also assessed at the end of intervention. Results: All exercise groups showed a similar VO2max increase of ∼15% (HIIT: 34.3 ± 4.4 vs 39.1 ± 5.4; MICT: 34.9 ± 5.0 vs 39.4 ± 7.2; and alternating HIIT-MICT: 34.4 ± 5.0 vs 40.3 ± 4.6 mL kg−1min−1) compared to baseline and CON (all p

Background and Objective: Differentiation of white adipose tissue into brown through hormonal and non-hormonal factors, causes weight loss and weakens in obese and overweight people. This study was performed to determine the effect of 12 weeks of interval exercise with different intensities on serum levels of fibroblast growth factor 21 and myostatin in obese and overweight males. Methods: This clinical trial study was done on 47 obese and overweight males (20.5±0.73 years old). Subjects were randomly divided into four groups: control, interval exercise with low intensity, moderate intensity and high intensity. The exercise program consisted of 12weeks of interval exercise with light, medium and heavy intensity respectively with 58-63, 73-78 and 88-93 percent of Reserve heart rate for 25 to 63 minutes and three sessions per week. Serum indices of fibroblast growth factor 21 and myostatin were measured using fasting blood sample 48 hours before and after exercise program using ELISA method. Results: Performing 12 weeks of interval training with different intensities was not contribute to significant changes in the serum levels of fibroblast growth factor 21 and myostatin. Implementation of interval exercise at moderate and high intensities was associated with reduction of body fat percentage and increasing in maximal oxygen consumption (VO2max) in overweight and obese men (P

Arterial stiffness is a reliable independent predictor of cardiovascular events. Exercise training might enhance arterial compliance through improved metabolic health status. Different modes of exercise may have different effects on arterial stiffness. However, the interactions among different modes of exercise on endothelial senescence, the development of arterial vascular stiffness, and the associated molecular mechanisms are not completely understood. In this narrative review, we evaluate the current evidence focusing on the effects of various exercise modes on arterial stiffness and vascular health, and the known underlying physiological mechanisms are discussed as well. Here, we discuss the most recent evidence of aerobic exercise, high-intensity interval training (HIIT), and resistance exercise (RE) on arterial stiffness and endothelial senescence in physiological and cellular studies. Indeed, aerobic, HIIT, and progression RE-induced arterial compliance may reduce arterial stiffness by effectively promoting nitric oxide (NO) bioavailability and reducing endothelial senescence. However, the transient increase in inflammation and sympathetic activation may contribute to the temporary elevation in arterial stiffness following whole-body high-intensity acute resistance exercise. [ABSTRACT FROM AUTHOR]

The practice of exercise can change biological markers. Thus, the use of saliva to define possible biomarkers has increased with the advances in "omics" techniques. Therefore, this study analyzed the salivary proteomic profile in young adults before and after interval exercise. Five adults, without comorbidities and with normal salivary flow, aged between 20 and 35 years (3 men and 2 women) were selected. The collection of stimulated (SS) and non-stimulated (NSS) saliva was done before (BE) and after (AE) exercise, which consisted of interval exercise with 5 min walking on a treadmill and 5 min at rest, during a total of 40 min. The proteins were extracted individually and processed by label-free proteomics. There was no significant difference between BE and AE salivary flows. For SS, 69 and 60 proteins were found BE (12 exclusives) and AE (3 exclusives), respectively. Ten subunits of immunoglobulins (8 more than twofold), as well as Lysozyme C and Cystatin-S, were increased AE compared to BE. Six hemoglobin's isoforms were decreased AE compared to BE. For NSS, 76 and 65 proteins were found BE (18 exclusives) and AE (7 exclusives), respectively. Albumin was increased AE, while Basic salivary proline-rich protein 1 and 2 decreased. Apolipoprotein A-I was identified exclusively AE compared to BE. The salivary proteome after interval exercise suggests increase of immunity. [ABSTRACT FROM AUTHOR]

IntroductionActivities such as high-intensity resistance training (HIRT) and high-intensity interval training (HIIT) may be more time-efficient modes to stimulate rapid changes in performance and body composition. There is little research evaluating the combined effects of HIRT and HIIT on body composition and strength, particularly when paired with nutritional supplementation.PurposeTo evaluate the chronic effects of pre- and post-workout supplementation on body composition and strength, and to understand sex-specific responses.Materials and methods64 untrained males (n = 23) and females (n = 41) (mean ± standard deviation; age: 33.2 ± 10.0 years; %fat: 31.6 ± 7.4%) were randomized to either (1) pre-post supplementation [SUP (n = 25); pre = multi-ingredient caffeine/HMB/vit D; post = whey protein/carbohydrates/glucosamine/vitamins], (2) placebo [PL (n = 24); non-caloric], or (3) control [CON (n = 15)]. All participants completed one repetition max (1RM) strength testing for leg press and bench press at baseline and week 6. Estimates of fat mass (FM) and lean mass (LM) were measured via dual energy x-ray absorptiometry. Participants in the SUP or PL group completed a 6-week supervised exercise intervention consisting of a full-body HIRT workout (3 × 6–8 reps) followed by a HIIT treadmill run (6 × 1 min run: 1 min rest) twice per week. Outcomes were evaluated by separate repeated measure ANOVAs (2 × 3).ResultsThere were no differences in FM between groups or sex (p = 0.133–0.851). LM increased from baseline to post-testing for all groups [Mean difference [MD(Post-Pre) ± Standard Error (SE) = 0.78 ± 0.12 kg; p < 0.001]. While not significant (p = 0.081), SUP gained more LM compared to PL [MD(SUP-PL) ± SE = 3.5 ± 3.3 kg] and CON [MD(SUP-CON) ± SE = 5.2 ± 3.8 kg]. LM increased over time for both males (0.84 ± 0.24 kg; p = 0.003) and females (0.73 ± 0.14 kg; p < 0.001). The SUP group resulted in a significant increase in 1RM leg press compared to the CON group (89.9 ± 30.8 kg; p = 0.015), with no significant differences compared to PL (p = 0.409). The SUP group had greater increases in 1RM bench press compared to the CON group (9.8 ± 1.8 kg; p < 0.001), with no significant differences compared to PL (p = 0.99). Both sexes increased upper- (5.5 ± 0.7 kg; p < 0.001) and lower-body strength (69.8 ± 4.5 kg p < 0.001) with training.ConclusionNutrient supplementation timing appears to augment body composition changes and strength compared to control. Pre-/post-nutrient timing may support greater increases in LM and lower- and upper-body strength in both men and women.Clinical trial registration[https://clinicaltrials.gov/ct2/show/NCT04230824?cond=NCT04230824&draw=2&rank=1], identifier [NCT04230824].

Background: Menopause represents a turning point where vascular damage begins to outweigh reparative processes, leading to increased cardiovascular disease (CVD) risk. Exercise training reduces CVD risk in postmenopausal females via improvements in traditional risk factors and direct changes to the vasculature. We assessed the effect of moderate (MODERATE‐IT) versus heavy (HEAVY‐IT) intensity interval exercise training upon markers of cardiovascular health and vascular repair in postmenopausal females. Methods: Twenty‐seven healthy postmenopausal females (56 ± 4 yr) were assigned to 12 weeks of either MODERATE‐IT or HEAVY‐IT, twice per week. MODERATE‐IT consisted of 10s work, and 10s active recovery repeated for 30 min. HEAVY‐IT comprised 30s work, and 30s active recovery repeated for 21 ± 2 min. Endothelial function (flow‐mediated dilation), arterial stiffness (pulse wave velocity), and V̇O2peak were assessed pre‐training and post‐training. Blood samples were obtained pre‐training and post‐training for enumeration of circulating angiogenic cells (CACs), culture of CACs, and lipoprotein profile. Results: V̇O2peak increased 2.4 ± 2.8 ml/kg/min following HEAVY‐IT only (p < 0.05). Brachial blood pressure and endothelial function were unchanged with exercise training (p > 0.05). Peripheral pulse wave velocity reduced 8% with exercise training, irrespective of intensity (p < 0.05). Exercise training had no effect on lipoprotein profile or endothelin‐1 (p > 0.05). CAC adhesion to vascular smooth muscle cells (VSMC) increased 30 min post plating following MODERATE‐IT only (p < 0.05). Conclusions: HEAVY‐IT was more effective at increasing V̇O2peak in postmenopausal females. The ability of CACs to adhere to VSMC improved following MODERATE‐IT but not HEAVY‐IT. Interval training had the same effect on endothelial function (no change) and arterial stiffness (reduced), regardless of exercise intensity. [ABSTRACT FROM AUTHOR]

Purpose: Due to the intervals' nature of soccer, the aim of this study was to evaluate intermittent protocol of incremental laboratory test in measuring the physiological parameters of soccer players. Methods: Eighteen young soccer players (Mean ± SD; age 16.78 ± 0.78 years, weight 61.33 ± 9.44 kg, height 177 ± 6.75 Cm) voluntarily participated into two incremental laboratory tests (continuous and intermittent protocol) on the HP Cosmos Treadmill with 48-hour interval and then Bangesbo field test was performed. The subjects' cardiopulmonary parameters were measured by gas analyzer, metalyzer3b model, and blood lactate before and after the tests with lactometer Scout model. Statistical analysis was performed by ANOVA Repeated Measure, paired t-test and Pearson correlation coefficient at the significant level P ≤ 0.05. Results: There was no significant difference between the physiological factors of continuous and intermittent tests, but there was a significant difference between the distance at continuous and intermittent tests (P = 0.031). There was a significant positive relationship between the performance of the Bangesbo test with the maximum oxygen consumption (r = 0.64, P= 0.011) and distance (r = 0.62, P = 0.018) of the intermittent test. Conclusion: The significant positive correlation between the maximum oxygen consumption of the intermittent test and the performance of the Bangesbo test, Higher distance in intermittent test and significant positive correlation between performance of Bangesbo test and distance of intermittent incremental test; It may be explained by the similarity of the intermittent test to the interval component of the playing soccer and this observing suggest to consider component of athlete's activity when defining the incremental test. [ABSTRACT FROM AUTHOR]

Key pointsContinuous high-intensity constant-power exercise is unsustainable, with maximal oxygen uptake (V̇O2 max ) and the limit of tolerance attained after only a few minutes. Performing the same power intermittently reduces the O2 cost of exercise and increases tolerance. The extent to which this dissociation is reflected in the intramuscular bioenergetics is unknown. We used pulmonary gas exchange and 31 P magnetic resonance spectroscopy to measure whole-body V̇O2, quadriceps phosphate metabolism and pH during continuous and intermittent exercise of different work:recovery durations. Shortening the work:recovery durations (16:32 s vs. 32:64 s vs. 64:128 s vs. continuous) at a work rate estimated to require 110% peak aerobic power reduced V̇O2, muscle phosphocreatine breakdown and muscle acidification, eliminated the glycolytic-associated contribution to ATP synthesis, and increased exercise tolerance. Exercise intensity (i.e. magnitude of intramuscular metabolic perturbations) can be dissociated from the external power using intermittent exercise with short work:recovery durations.AbstractCompared with work-matched high-intensity continuous exercise, intermittent exercise dissociates pulmonary oxygen uptake (V̇O2) from the accumulated work. The extent to which this reflects differences in O2 storage fluctuations and/or contributions from oxidative and substrate-level bioenergetics is unknown. Using pulmonary gas-exchange and intramuscular 31 P magnetic resonance spectroscopy, we tested the hypotheses that, at the same power: ATP synthesis rates are similar, whereas peak V̇O2 amplitude is lower in intermittent vs. continuous exercise. Thus, we expected that: intermittent exercise relies less upon anaerobic glycolysis for ATP provision than continuous exercise; shorter intervals would require relatively greater fluctuations in intramuscular bioenergetics than in V̇O2 compared to longer intervals. Six men performed bilateral knee-extensor exercise (estimated to require 110% peak aerobic power) continuously and with three different intermittent work:recovery durations (16:32, 32:64 and 64:128 s). Target work duration (576 s) was achieved in all intermittent protocols; greater than continuous (252 ± 174 s; P

Abstract Background Menopause represents a turning point where vascular damage begins to outweigh reparative processes, leading to increased cardiovascular disease (CVD) risk. Exercise training reduces CVD risk in postmenopausal females via improvements in traditional risk factors and direct changes to the vasculature. We assessed the effect of moderate (MODERATE‐IT) versus heavy (HEAVY‐IT) intensity interval exercise training upon markers of cardiovascular health and vascular repair in postmenopausal females. Methods Twenty‐seven healthy postmenopausal females (56 ± 4 yr) were assigned to 12 weeks of either MODERATE‐IT or HEAVY‐IT, twice per week. MODERATE‐IT consisted of 10s work, and 10s active recovery repeated for 30 min. HEAVY‐IT comprised 30s work, and 30s active recovery repeated for 21 ± 2 min. Endothelial function (flow‐mediated dilation), arterial stiffness (pulse wave velocity), and V̇O2peak were assessed pre‐training and post‐training. Blood samples were obtained pre‐training and post‐training for enumeration of circulating angiogenic cells (CACs), culture of CACs, and lipoprotein profile. Results V̇O2peak increased 2.4 ± 2.8 ml/kg/min following HEAVY‐IT only (p 0.05). Peripheral pulse wave velocity reduced 8% with exercise training, irrespective of intensity (p 0.05). CAC adhesion to vascular smooth muscle cells (VSMC) increased 30 min post plating following MODERATE‐IT only (p

Mitochondrial dysfunction is a significant feature of type 2 diabetes. MOTS-C, a peptide derived from mitochondria, has positive effects on metabolism and exercise capacity. This study explored the impact of high and moderate-intensity interval exercises on mitochondrial MOTS-C alterations and their correlation with metabolic markers in male diabetic sand rats. Thirty male sand rats were divided into six groups: control, MIIT, DM + HIIT, DM + MIIT, DM, and HIIT (5 rats each). Diabetes was induced using a high-fat diet (HFD) combined with streptozotocin (STZ). The Wistar sand rats in exercise groups underwent 8 weeks of interval training of varying intensities. Post sample collection, protein expressions of PCG-1a, AMPK, and GLUT4 were assessed through Western blot analysis, while MOTS-C protein expression was determined using ELISA. Both exercise intensity and diabetes significantly affected the levels of PCG-1a, MOTS-C, GLUT4 proteins, and insulin resistance (p < 0.001). The combined effect of diabetes status and exercise intensity on these levels was also significant (p < 0.001). However, the diabetes effect varied when comparing high-intensity to moderate-intensity exercise. The moderate-intensity exercise group with diabetes showed higher levels of PCG-1a, MOTS-C, and GLUT4 proteins and reduced insulin resistance levels (p < 0.001). Exercise intensity (p = 0.022) and diabetes (p = 0.008) significantly influenced AMPK protein levels. The interplay between diabetes status and exercise intensity on AMPK protein levels was noteworthy, with the moderate-intensity diabetes group exhibiting higher AMPK levels than the high-intensity diabetes group (p < 0.001). In conclusion, exercise elevates the levels of PCG-1a, MOTS-C, GLUT4, and AMPK proteins, regulating insulin resistance in diabetic sand rats. Given the AMPK-MOTS-C mitochondrial pathway's mechanisms, interval exercises might enhance the metabolic rates and general health of diabetic rodents. [ABSTRACT FROM AUTHOR]

Trimethylamine N-oxide (TMAO) is linked to cardiovascular disease (CVD) through partly altered central hemodynamics. We sought to examine if a low-calorie diet plus interval exercise (LCD+INT) intervention reduces TMAO more than a low-calorie diet (LCD) program alone in relation to hemodynamics, prior to clinically meaningful weight loss. Women with obesity were randomized to 2 weeks of LCD (n = 12, ~1200 kcal/d) or LCD+INT (n = 11; 60 min/d, 3 min at 90% and 50% HRpeak, respectively). A 180 min 75 g OGTT was performed to assess fasting TMAO and precursors (carnitine, choline, betaine, and trimethylamine (TMA)) as well as insulin sensitivity. Pulse wave analysis (applanation tonometry) including augmentation index (AIx75), pulse pressure amplification (PPA), forward (Pf) and backward pressure (Pb) waveforms, and reflection magnitude (RM) at 0, 60, 120, and 180 min was also analyzed. LCD and LCD+INT comparably reduced weight (p < 0.01), fasting glucose (p = 0.05), insulin tAUC180min (p < 0.01), choline (p < 0.01), and Pf (p = 0.04). Only LCD+INT increased VO2peak (p = 0.03). Despite no overall treatment effect, a high baseline TMAO was associated with decreased TMAO (r = −0.45, p = 0.03). Reduced TMAO was related to increased fasting PPA (r = −0.48, p = 0.03). Lowered TMA and carnitine correlated with higher fasting RM (r = −0.64 and r = −0.59, both p < 0.01) and reduced 120 min Pf (both, r = 0.68, p < 0.01). Overall, treatments did not lower TMAO. Yet, people with high TMAO pre-treatment reduced TMAO after LCD, with and without INT, in relation to aortic waveforms.

Background: Performing multiple high-intensity interval training (HIIT) sessions in a compressed period of time (approximately 7–14 days) is called a HIIT shock microcycle (SM) and promises a rapid increase in endurance performance. However, the efficacy of HIIT-SM, as well as knowledge about optimal training volumes during a SM in the endurance-trained population have not been adequately investigated. This study aims to examine the effects of two different types of HIIT-SM (with or without additional low-intensity training (LIT)) compared to a control group (CG) on key endurance performance variables. Moreover, participants are closely monitored for stress, fatigue, recovery, and sleep before, during and after the intervention using innovative biomarkers, questionnaires, and wearable devices. Methods: This is a study protocol of a randomized controlled trial that includes the results of a pilot participant. Thirty-six endurance trained athletes will be recruited and randomly assigned to either a HIIT-SM (HSM) group, HIIT-SM with additional LIT (HSM + LIT) group or a CG. All participants will be monitored before (9 days), during (7 days), and after (14 days) a 7-day intervention, for a total of 30 days. Participants in both intervention groups will complete 10 HIIT sessions over 7 consecutive days, with an additional 30 min of LIT in the HSM + LIT group. HIIT sessions consist of aerobic HIIT, i.e., 5 × 4 min at 90–95% of maximal heart rate interspersed by recovery periods of 2.5 min. To determine the effects of the intervention, physiological exercise testing, and a 5 km time trial will be conducted before and after the intervention. Results: The feasibility study indicates good adherence and performance improvement of the pilot participant. Load monitoring tools, i.e., biomarkers and questionnaires showed increased values during the intervention period, indicating sensitive variables. Conclusion: This study will be the first to examine the effects of different total training volumes of HIIT-SM, especially the combination of LIT and HIIT in the HSM + LIT group. In addition, different assessments to monitor the athletes' load during such an exhaustive training period will allow the identification of load monitoring tools such as innovative biomarkers, questionnaires, and wearable technology. Trial Registration: clinicaltrials.gov, NCT05067426. Registered 05 October 2021—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05067426. Protocol Version Issue date: 1 Dec 2021. Original protocol. Authors: TLS, NH. [ABSTRACT FROM AUTHOR]

Coronary artery disease is the main cause of death worldwide. Coronary artery bypass graft (CABG) is a preferred treatment option for multi-vessel disease and left main disease patients. Physical training (recovery) enhances exercise tolerance, an activity of daily living, and quality of life in this patient. For this, the aim of the current study was to investigate the effect of acute high-intensity interval exercise on post-exercise blood pressure in CABG patients. In this study, all patients underwent open-heart surgery at least 1 month before involvement in the study. All Subjects were included after Medical rigorous screening. Participants carried out two experimental sessions of high-intensity interval exercise (HIIE) and mild continuous exercise (MCE) with a minimum of 72 h intervals: This study employed a randomized, cross-over design, Brachial systolic blood pressure (SBP) and diastolic blood pressure (DBP) and heart rate (HR) were measured Immediately before (pre) and after (post) and approximately15 min(post-15) and 30 min (post-30) after each exercise bout. The Split-Plot Analysis of Variance with repeated measures (group × time) was used to analyze the data. Significant post-exercise increases in SBP, and HR were seen following each protocol (p<0.05). Following two bouts, SBP decreased at 15- and 30-min postexercise in two groups but this decline was more in the HIIE group than MCE. Based on the findings of this study, both high-intensity intermittent and continuous exercise can improve heart function in CABG patients by diminishing BP. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to compare the acute physiological, perceptual, and enjoyment responses between bodyweight high-intensity interval exercise (BW-HIIE) and treadmill running high-intensity interval exercise HIIE (RUN-HIIE). Methods: Twelve adults [age: 29.5 ± 5.3 years; weight: 70.9 ± 15.0 kg; height: 167.9 ± 8.9 cm; peak oxygen consumption (VO2 peak): 48.7 ± 6.5 ml min−1·kg−1] performed both RUN-HIIE and BW-HIIE. RUN-HIIE consisted of two sets of 5, 60-s (s) run intervals at 100% of the speed achieved during VO2 peak testing followed by 60s of walking at 4.02 km/h. BW-HIIE consisted of two sets of 5, 60s 'all-out' effort calisthenic exercises followed by 60s of marching in place at 100 steps per minute. Oxygen consumption (VO2), blood lactate (Blac), heart rate (HR), and rating of perceived exertion (RPE) were measured during exercise. Physical activity enjoyment (PACES) was assessed post-exercise. Creatine Kinase (CK) was measured before exercise and 48-h post-exercise. Muscle soreness was assessed before exercise, post-exercise, and 48-h post-exercise. Results: Oxygen consumption relative to VO2 peak was higher (p < 0.001) during RUN-HIIE (88 ± 3%) compared to BW-HIIE (77 ± 4%). HR relative to HRpeak was higher (p = 0.002) for RUN-HIIE (93 ± 1%) compared to BW-HIIE (88 ± 2%). Blac was higher (p < 0.001) after BW-HIIE (11.2 ± 3.2 mmol/l) compared to RUN-HIIE (6.9 ± 2.0 mmol/l). Average RPE achieved was higher (p = 0.003) during BW-HIIE (16 ± 2) than RUN-HIIE (14 ± 2). PACES was similar for RUN-HIIE and BW-HIIE (p > 0.05). No differences (p > 0.05) in CK were observed between RUN-HIIE and BW-HIIE. Conclusion: Our results indicate 'all-out' calisthenic exercise can elicit vigorous cardiorespiratory, Blac, and RPE responses. Implementing this style of exercise into training requires minimal space, no equipment, and may elicit cardiometabolic adaptations seen with traditional forms of high-intensity exercise. [ABSTRACT FROM AUTHOR]

Patients with type 1 diabetes mellitus (T1DM) have many benefits from regular exercise, including improved quality of life, lower blood pressure, improved lipid profile, increased insulin sensitivity, decreased insulin dose requirements, improved endothelial function, and reduced risk of micro- and macrovascular complications, as well as overall mortality. Despite these benefits, T1DM patients often do not get enough physical activity (PA) and are less physically active than their non-diabetic peers. The main reason for the low PA in patients with T1DM is the difficulty of glycemic management and the fear of developing hypoglycemia during exercise. Different types of training, such as moderate to high intensity exercise, high intensity interval training, have different effects on glycemic activity during exercise, which can be used to prevent the development of hypoglycemic reactions during and after exercise, along with carbohydrate intake and insulin dose adjustment. Higher-intensity exercise, as well as greater frequency and duration, are associated with a greater reduction in the risk of overall and cardiovascular mortality. Regular physical activity has a positive effect on reducing the risk of micro- and macrovascular complications, general and cardiovascular mortality in patients with type 1 diabetes, regardless of the quality of glycemic control, which can be used for prevention of T1DM complications.

ObjectiveThe purpose of this study was to compare the acute physiological, perceptual, and enjoyment responses between bodyweight high-intensity interval exercise (BW-HIIE) and treadmill running high-intensity interval exercise HIIE (RUN-HIIE).MethodsTwelve adults [age: 29.5 ± 5.3 years; weight: 70.9 ± 15.0 kg; height: 167.9 ± 8.9 cm; peak oxygen consumption (VO2 peak): 48.7 ± 6.5 ml min−1·kg−1] performed both RUN-HIIE and BW-HIIE. RUN-HIIE consisted of two sets of 5, 60-s (s) run intervals at 100% of the speed achieved during VO2 peak testing followed by 60s of walking at 4.02 km/h. BW-HIIE consisted of two sets of 5, 60s ‘all-out’ effort calisthenic exercises followed by 60s of marching in place at 100 steps per minute. Oxygen consumption (VO2), blood lactate (Blac), heart rate (HR), and rating of perceived exertion (RPE) were measured during exercise. Physical activity enjoyment (PACES) was assessed post-exercise. Creatine Kinase (CK) was measured before exercise and 48-h post-exercise. Muscle soreness was assessed before exercise, post-exercise, and 48-h post-exercise.ResultsOxygen consumption relative to VO2 peak was higher (p 0.05). No differences (p > 0.05) in CK were observed between RUN-HIIE and BW-HIIE.ConclusionOur results indicate ‘all-out’ calisthenic exercise can elicit vigorous cardiorespiratory, Blac, and RPE responses. Implementing this style of exercise into training requires minimal space, no equipment, and may elicit cardiometabolic adaptations seen with traditional forms of high-intensity exercise.

Background: This study investigated the acute effects of various doses of nitrate-rich beetroot juice on the responses to high-intensity interval exercise in women., Methods: A double-blinded, randomized, placebo-controlled, crossover trial was conducted with 13 recreationally active young women (age = 23 ± 2 years). All participants performed interval exercise (8 × 1-min bouts of cycling at 85% of peak power output [PPO] interspersed with 1-min active recovery at 20% of PPO) 2.5 h after consumption of the randomly assigned beetroot juice containing 0 mmol (placebo), 6.45 mmol (single-dose), or 12.9 mmol (double-dose) N O 3 - . The heart rate (HR), blood pressure, blood lactate, blood glucose, oxygen saturation, rating of perceived exertion (RPE), and emotional arousal were assessed., Results: Nitrate supplementation significantly altered the HR and RPE responses across the three trials. The mean HR was lower in the single- and double-dose groups than in the placebo control group during both work intervals and recovery periods, as well as across the overall protocol (all p  < .05). The mean RPE was lower in the single- and double-dose groups than in the control group during recovery periods and across the overall protocol (all p  < .001). However, there was no significant difference in either HR or RPE between the single- and double-dose groups at any time point., Conclusions: Acute nitrate ingestion led to significant decreases in the mean HR and RPE during high-intensity interval exercise, but no additional benefit was observed with higher nitrate content. These findings may assist practitioners in implementing more effective nitrate supplementation strategies during high-intensity interval exercise.

Background and Objective: Differentiation of white adipose tissue into brown through hormonal and non-hormonal factors, causes weight loss and weakens in obese and overweight people. This study was performed to determine the effect of 12 weeks of interval exercise with different intensities on serum levels of fibroblast growth factor 21 and myostatin in obese and overweight males. Methods: This clinical trial study was done on 47 obese and overweight males (20.5±0.73 years old). Subjects were randomly divided into four groups: control, interval exercise with low intensity, moderate intensity and high intensity. The exercise program consisted of 12weeks of interval exercise with light, medium and heavy intensity respectively with 58-63, 73-78 and 88-93 percent of Reserve heart rate for 25 to 63 minutes and three sessions per week. Serum indices of fibroblast growth factor 21 and myostatin were measured using fasting blood sample 48 hours before and after exercise program using ELISA method. Results: Performing 12 weeks of interval training with different intensities was not contribute to significant changes in the serum levels of fibroblast growth factor 21 and myostatin. Implementation of interval exercise at moderate and high intensities was associated with reduction of body fat percentage and increasing in maximal oxygen consumption (VO2max) in overweight and obese men (P<0.05). Conclusion: Performing 12 weeks of low, medium and high intensity interval training without changing the serum level of fibroblast growth factor 21 and myostatin has a beneficial effect on improving body composition and increasing VO2max in obese and overweight young males. [ABSTRACT FROM AUTHOR]

High-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) alone has been shown to improve metabolic health, but the effects of alternating the two training approaches as often practiced in real life remained unclear. The purpose of the current study was to examine the effects of HIIT or MICT alone or alternating HIIT-MICT on cardiometabolic responses in inactive obese middle-aged men. Forty-two participants (age: 42 ± 5 y; BMI: 26.3 ± 2.1 kg m−2) were randomly assigned to four groups: HIIT (12 x 1-min running bouts at 80–90% HR max interspersed with 1-min active recovery at 50% HR max), MICT (40-min brisk walk at 65–70% HR max), alternating HIIT-MICT or a non-exercise control group (CON). Exercise sessions were conducted three times per week for 16 weeks. Maximal oxygen uptake (VO 2max), body composition (by bioelectrical impedance analysis), blood pressure, fasting blood glucose, insulin resistance (HOMA-IR) and lipid profile were assessed at baseline and after the 16-week intervention. Enjoyment and self-efficacy were also assessed at the end of intervention. All exercise groups showed a similar VO 2max increase of ∼15% (HIIT: 34.3 ± 4.4 vs 39.1 ± 5.4; MICT: 34.9 ± 5.0 vs 39.4 ± 7.2; and alternating HIIT-MICT: 34.4 ± 5.0 vs 40.3 ± 4.6 mL kg−1min−1) compared to baseline and CON (all p < 0.05). Weight, BMI, % fat and waist circumference also showed similar reductions in all exercise groups compared to baseline and CON (all p < 0.05). No significant group difference was observed for all blood markers. Compared to baseline, total cholesterol decreased after HIIT-MICT, while HIIT significantly decreased fasting insulin level and improved insulin resistance (p < 0.05). Enjoyment, self-efficacy and adherence were similar among all exercise groups. HIIT or MICT alone or alternating HIIT-MICT similarly improve cardiovascular fitness and body composition in obese middle-aged men despite differences in total training volume and time commitment. [ABSTRACT FROM AUTHOR]

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Interval training is a form of exercise that involves intermittent bouts of relatively intense effort interspersed with periods of rest or lower-intensity exercise for recovery. Low-volume high-intensity interval training (HIIT) and sprint interval training (SIT) induce physiological and health-related adaptations comparable to traditional moderate-intensity continuous training (MICT) in healthy adults and those with chronic disease despite a lower time commitment. However, most studies within the field have been conducted in men, with a relatively limited number of studies conducted in women cohorts across the lifespan. This review summarizes our understanding of physiological responses to low-volume interval training in women, including those with overweight/obesity or type 2 diabetes, with a focus on cardiorespiratory fitness, glycemic control, and skeletal muscle mitochondrial content. We also describe emerging evidence demonstrating similarities and differences in the adaptive response between women and men. Collectively, HIIT and SIT have consistently been demonstrated to improve cardiorespiratory fitness in women, and most sex-based comparisons demonstrate similar improvements in men and women. However, research examining insulin sensitivity and skeletal muscle mitochondrial responses to HIIT and SIT in women is limited and conflicting, with some evidence of blunted improvements in women relative to men. There is a need for additional research that examines physiological adaptations to low-volume interval training in women across the lifespan, including studies that directly compare responses to MICT, evaluate potential mechanisms, and/or assess the influence of sex on the adaptive response. Future work in this area will strengthen the evidence-base for physical activity recommendations in women. [ABSTRACT FROM AUTHOR]

High-intensity interval training (HIIT) promotes positive cardiometabolic and body composition changes. Essential amino acids (EAA) may support changes associated with HIIT, but evaluation of potential synergistic effects is lacking. The purpose of this study was to compare independent and combined effects of HIIT and EAA on total body composition and metabolism in men and women considered overweight/obese; an exploratory aim was to evaluate the modulatory effects of sex. Sixty-six healthy adults (50% female; Age: 36.7 ± 6.0 years; BMI: 32.0 ± 4.2 kg/m2) completed 8 weeks of: (1) HIIT, 2 days/weeks; (2) EAA supplementation, 3.6 g twice daily; (3) HIIT + EAA; or (4) control. Body composition, resting metabolic rate (RMR), substrate metabolism (respiratory exchange ratio; RER), and cardiorespiratory fitness were measured at baseline, 4 weeks, and 8 weeks; cardiometabolic blood markers were measured at baseline and 8 weeks. Differences between groups were assessed by linear mixed models covaried for baseline values, followed by 95% confidence intervals (CI) on adjusted mean change scores. There were no significant changes in body composition (p > 0.05) for any group. Changes in RER, but not RMR, occurred with HIIT (mean change; [95% CI]: − 0.04; [− 0.07, − 0.02]) and EAA (− 0.03; [− 0.06, − 0.01]) after 8 weeks. Cardiorespiratory fitness increased following 8 weeks of HIIT (+ 5.1 ml/kg/min [3.3,6.8]) and HIIT + EAA (+ 4.1 ml/kg/min [1.0,6.4]). Changes with HIIT + EAA were not significantly different from HIIT. There were no changes in cardiometabolic markers (p > 0.05) and no sex interaction (p > 0.05). HIIT is efficacious for promoting positive changes in cardiorespiratory fitness and resting substrate metabolism in adults considered overweight/obese. Addition of EAA did not significantly enhance HIIT-induced adaptations. ClinicalTrials.gov ID#NCT04080102. [ABSTRACT FROM AUTHOR]

The purpose of this study was to confirm that blood lactate concentrations can be maintained at moderate to high steady state values during an entire interval training (IT) session (repetitions + rest). Forty-eight trained swimmers and track athletes performed four IT protocols consisting of 6-10 bouts between 1 and 3-min at ~5-10 mmol/L blood lactate concentrations with a passive recovery of 60 to 180-sec. Performance times were measured at every bout, while blood lactate concentrations and heart rate during recovery every other bout. One-way ANOVA was performed for comparisons and r-squared for the effect size (ES). Performance times were stable throughout each IT protocol (75 ± 8 and 77 ± 5-sec [swimmers and track athletes]; 67 ± 3-sec [swimmers]; 64 ± 3-sec [swimmers]; and 135 ± 6-sec [swimmers]). Despite some minor differences (p<0.05; ES, 0.28 to 0.37, large), blood lactate concentrations were maintained stable at moderate to high values during each IT protocol (5.85 ± 1.47 mmol/L; 5.64 ± 1.03 mmol/L; 9.29 ± 1.07 mmol/L; and 9.44 ± 1.12 mmol/L). HR decreased significantly from the beginning to the end of recovery (p<0.05; ES, 0.93 to 0.96, large). In conclusion, moderate to high blood lactate steady state concentrations can be sustained for ~20 to 60-min during an entire IT session (repetitions + rest) at a stable performance. This approach can optimize performance by stimulating the metabolic demands and the pace strategy during the middle section of endurance competitive events.