Resistance High-intensity Interval Training Research Articles

Effect of low-volume combined aerobic and resistance high-intensity interval training on vascular health in people with type 2 diabetes: a randomised controlled trial.

We compared the effects of low-volume combined aerobic and resistance high-intensity interval training (C-HIIT), combined moderate-intensity continuous training (C-MICT) and waitlist control (CON) on vascular health after 8-weeks of supervised training, and an additional 10-months of self-directed training, in adults with type 2 diabetes (T2D). Sixty-nine low active adults with T2D were randomised to 8-weeks of supervised C-HIIT (3 times/week, 78-min/week), C-MICT (current exercise guidelines, 4 times/week, 210-min/week) or CON. CON underwent usual care for 8-weeks before being re-randomised to C-HIIT or C-MICT. This was followed by 10-months of self-directed training for participants in C-HIIT and C-MICT. Vascular outcomes were evaluated at baseline, 8-weeks, and 12-months. After 8-weeks, supervised C-HIIT significantly improved relative flow-mediated dilation (FMD) compared with CON (mean difference [MD] 0.8% [0.1, 1.4], p = 0.025). Although not significantly different from CON, the magnitude of change in relative FMD following 8-weeks of supervised C-MICT was similar (MD 0.8% [-0.1, 1.7], p = 0.080). There were no differences in haemodynamic indices, carotid-femoral pulse wave velocity (cfPWV), or aortic reservoir pressure between groups at 8-weeks. After 12-months, there was a significant reduction in haemodynamic indices (time effect, p < 0.05) for both C-HIIT and C-MICT, with no between-group difference. The reduction in cfPWV over 12-months was significantly greater in C-MICT than C-HIIT (group × time effect, p = 0.018). There was no difference in FMD over time or between groups at 12-months. Short-term supervised C-HIIT and C-MICT both increased brachial artery FMD compared with CON. Long-term C-HIIT and C-MICT were beneficial for improving haemodynamic indices, but not brachial artery FMD. C-MICT was superior to C-HIIT for improving cfPWV at 12-months. Australian New Zealand Clinical Trials Registry Identifier ACTRN12615000475549.

Highlighting the effect of reduced training volume on maintaining hormonal adaptations obtained from periodized resistance training in sarcopenic older women

ABSTRACT Background This study investigated the impact of the High Intensity Interval Resistance Training (HIIRT) protocol on hormonal changes in older women. Research design and methods Forty sarcopenic women were divided into an experimental group (EX = 30) and a control group (C = 10). The EX-group was further divided into Maintenance Training 1 (MT1 = 10), Maintenance Training 2 (MT2 = 10), and Detraining (DT = 10). The participants underwent 8 weeks of resistance training, consisting of hypertrophy and strength cycles. Following this, the EX-group had a 4-week period with no exercise or a reduced training volume. Measurements were taken at three time points. Results After 8 weeks, the EX-group showed significant improvements in Insulin Like Growth Factor-1 (IGF-1), Myostatin (MSTN), Follistatin (Fstn), Growth Hormone (GH) and Cortisol (Cort) compared to the control group. During the volume reduction period, there were no significant differences between MT1 and MT2 groups, but both groups saw increases in IGF-1, Fstn, GH, and decreases in MSTN and Cort compared to the DT group. Conclusions These findings suggest that performing at least one training session per week with the HIIRT protocol is crucial for maintaining hormonal adaptations in sarcopenic older women.

Self-selected or fixed: is there an optimal rest interval for controlling intensity in high-intensity interval resistance training?

This study investigated the effects of different rest interval strategies during high-intensity interval resistance training (HIRT) on cardiorespiratory, perceptual, and enjoyment responses among trained young men. Sixteen men experienced with HIRT underwent cardiopulmonary exercise testing and were familiarized with the exercises and HIRT protocol. On the subsequent three visits, interspaced 48-72h, participants performed HIRT sessions with different rest intervals in a randomized order: 10s and 30s fixed rest intervals (FRI-10 and FRI-30), and self-selected rest interval (SSRI). Oxygen uptake (VO2), heart rate (HR), and recovery perception (Total Quality Recovery Scale) were measured during HIRT, while enjoyment responses (Physical Activity Enjoyment Scale) were assessed immediately after the sessions. The VO2 during exercise was greater in FRI-10 than FRI-30 (55% VO2max and 47% VO2max, respectively, p = 0.01), while no difference occurred between SSRI and bouts performed with fixed intervals (52% VO2max vs. FRI, p > 0.05). HR, excess post-exercise oxygen consumption (EPOC), recovery perception, and enjoyment responses were similar across conditions (p > 0.05). Exercise intensity was not affected by the rest interval strategy. High exercise intensity was maintained in sessions performed with FRI or SSRI, without negative repercussions on the duration of training sessions and enjoyment responses after exercise sessions.

The Effect of Sports Activity and Vitamin D Intake on Serum Eutoxin-1 and Superoxide Dismutase Levels in Overweight Women with Vitamin D Deficiency: A Clinical Trial Study

Introduction: Being overweight and having vitamin D deficiency are associated with oxidative stress and low-grade chronic inflammation, resulting in various diseases. In the present study, changes in the levels of Eutoxin-1 and superoxide dismutase (SOD) were evaluated after 8 weeks of high-intensity interval resistance training (HIIRT) and vitamin D intake in overweight women with vitamin D deficiency. Method: In this clinical trial study, 52 overweight women with vitamin D deficiency were purposefully selected and then randomly assigned to exercise, vitamin D, exercise+vitamin D (combined), and control groups. HIIRT was performed 3 times a week in three sets with an intensity of 80% of a maximum repetition. Vitamin D was taken at a dose of 50,000 units weekly. Data were analyzed using paired t-test, one-way ANOVA, and Kruskal-Wallis tests with a significant level of less than 0.05. Results: After 8 weeks, SOD activity increased in the experimental groups, and the level of Eutoxin-1 decreased significantly. In addition, the rate of changes in SOD and Eutoxin-1 levels in the combined group was higher than those in the vitamin D group; however, no significant difference was observed between the exercise and combination groups (P&lt;0.05). Conclusion: It seems that HIIRT and vitamin D intake can increase SOD activity and up-regulate Eutoxin-1 in overweight women. Moreover, co-administration of HIIRT with vitamin D intake can have stronger effects in reducing the inflammatory-oxidative effects of overweight and vitamin D deficiency by increasing SOD and decreasing Eutoxin-1, compared to the intervention of vitamin D consumption.

Combined Dietary Education and High-Intensity Interval Resistance Training Improve Health Outcomes in Patients with Coronary Artery Disease.

Background: Reducing cardiovascular risk through lifestyle changes that include a heart-healthy diet and regular exercise is recommended in the rehabilitation of patients with coronary artery disease (CAD). We pilot-tested the effectiveness of a dietary-education and high-intensity interval resistance training (DE–HIIRT) program on healthy food choices and associated anthropometric variables in patients with established CAD. Methods: A total of 22 participants, aged 60.0 ± 7.2 years, were enrolled in the study. Over 3 months, under the guidance and supervision of a physiotherapist, participants performed the resistance exercises 2×/week in a group setting (cohort of 11). Participants additionally attended three sessions of dietary education led by a dietician. Participants demonstrated their knowledge and understanding of dietary education by picking heart-healthy foods by reading food labels. Outcomes included change in diet (measured using the tricipital skinfold thickness Mediterranean Diet Adherence questionnaire (MEDAS-14) and the Food Consumption Frequency Questionnaire (FCFQ)) and anthropometric measurements (body composition, body circumference, and tricipital skinfold thickness). A paired t-test was performed to analyze the differences between the baseline and post-intervention results. Results: Participants significantly increased their consumption of vegetables (p = 0.04) and lowered their consumption of sweet snacks (p = 0.007), pastries (p = 0.02), and processed food (p = 0.05). Significant improvements in body mass index (p = 0.001), waist circumference (p = 0.0001), hip circumference (p = 0.04), and body fat (p = 0.0001) were also achieved. Conclusion: Making lifestyle changes that include both diet and exercise is essential in the management of CAD. The HIIRT program combined with dietary changes shows promise in achieving weight-loss goals in this population and needs to be further investigated with appropriate study designs.

Intensity Dependent Effects of Interval Resistance Training on Myokines and Cardiovascular Risk Factors in Males With Obesity.

ObjectiveTo determine the effects of different intensities of interval resistance training (IRT) protocols on the levels of select myokines (decorin, follistatin, myostatin, activin A, transforming growth factor beta-1 [TGF-β1]), and cardiometabolic and anthropometric measures in males with obesity.MethodsForty-four obese males (age: 27.5 ± 9.4 yr.; height: 165.4 ± 2.8 cm; weight: 97.9 ± 2.6 kg and BMI: 35.7 ± 4.3 kg/m2) were randomly assigned to one of four groups (n=11 per group): low-intensity interval resistance training (LIIRT), moderate-intensity interval resistance training (MIIRT), high-intensity interval resistance training (HIIRT) or control (C). The LIIRT group performed 10 exercises in 3 sets of 40% (20 repetitions), the MIIRT group performed 10 exercises in three sets of 60% (13 repetitions), and the HIIRT group performed 10 exercises in three sets of 80% (10 repetitions) of one maximum repetition (1RM), which were followed with active rest of 20% of 1RM and 15 repetitions. The resistance training groups exercised ~70 min per session, 3 days per week, for 12 weeks. Measurements were taken at baseline and after 12 weeks of exercise training.ResultsBaseline levels of myokines, cardiovascular risk factors, anthropometry, body composition, and cardio-respiratory fitness were not different between the four groups (p>0.05). The group x time interactions for decorin, activin A, follistatin, myostatin, and TGF-β1, total cholesterol (TC), triglyceride (TG), high-density cholesterol (HDL), low-density cholesterol (LDL), anthropometry, body composition, and cardio-respiratory fitness were statistically significant (p<0.05). There were increases in post-test values for decorin, follistatin, HDL (p<0.05) and decreases in TC, TG, TGF-β1, LDL, and myostatin levels in the LIIRT, MIIRT, and HIIRT groups compared to pretest values (p<0.05). Changes in fat mass, VO2peak, HDL, TG, glucose, activin A, decorin were not significant in LIIRT compared to the control group, while changes in activin A, follistatin, and TFG-β1 levels were greater in HIIRT and MIIRT groups compared to the LIIRT group (p<0.05).ConclusionThe LIIRT, MIIRT, and HIIRT protocols all produced beneficial changes in decorin, activin A, follistatin, myostatin, and TGF-β1 levels, and cardiometabolic risk factors, with greater effects from the MIIRT and HIIRT protocols compared to LIIRT.

The effects of a structured-exercise training program on erectile function, cardiovascular and respiratory parameters in men following prostate cancer treatment: Preliminary results from a randomised, controlled clinical trial in prostate cancer survivorship

ABSTRACT Introduction Prostate cancer (PC) treatments can cause significant cardiovascular and sexual dysfunctions. There is limited data on the effects of structured exercise interventions specifically on the improvements of erectile function (EF) in the context of cardiovascular health and PC survivorship. It is postulated that structured physical exercise programs can result in positive changes in biomarkers of cardiovascular health through cardiovascular remodelling and in turns, will improve penile haemodynamic and EF recovery in PC men with erectile dysfunction (ED). Objective To explore the efficacy of structured-exercise training on EF, cardiorespiratory fitness (V̇O2peak), exercise capacity (peak power output; PPO) and vascular health (pulse wave velocity; PWV) in men with ED in the context of PC survivorship. Methods Following ethics approval, men who underwent radical prostatectomy and reported mild-to-moderate ED (defined as International Index of Erectile Function (IIEF-5) score of 8 to 21) were recruited and randomised to complete a thrice-weekly 12-week of structured aerobic and resistance high-intensity interval training (HIIT) intervention, or usual care. Changes in EF (based on IIEF-5 scores), V̇O2peak, PPO and PWV were assessed at baseline and 12 weeks follow-up. Results Of the 33 patients referred to the study, seven were ineligible due to severe (n=5) or normal (n=2) erectile function, with 12 agreeing to participate and blindly randomise into structured HIIT and usual care groups. Attendance to the 144 scheduled exercise sessions was 100%, with no study-related adverse events. At baseline, 75% of participants had a low V̇O2peak compared to normative data. After 12 weeks, EF (mean improvement in IIEF-5 by 5 points), V̇O2peak (INT=+3.7 mL/kg/min, CON=+0.4 mL/kg/min), absolute PPO (INT=+35 W, CON=+3 W) and PWV (INT=-3.16 m/s, CON=-0.95 m/s) were greater in the intervention group compared with the usual care group. Conclusions A 12-week structured HIIT exercise program is feasible, safe and has been shown to improve EF, cardiorespiratory fitness, exercise capacity and vascular health in men with PC. Disclosure Work supported by industry: no.

Influence of HIIRT With Fixed and Self-Selected Recovery Intervals on Physiological, Affective, and Enjoyment Responses

ABSTRACT Purpose: Recovery-interval strategies may influence physiological and psychological responses during highintensity interval resistance training (HIIRT). This study compared the intensity, performance, and psychological outcomes during all-out effort HIIRT performed with fixed (FRI) and self-selected (SSRI) recovery intervals. Methods: Sixteen trained males (27.2 ± 4.1 years; 84.5 ± 8.9 kg; 55.8 ± 7.1 mL.kg−1.min−1) performed HIIRT bouts interspersed with FRI (10 s) and SSRI (15.3 ± 7.9 s). Results: Relative heart rate (%HRmax) and oxygen uptake (%VO2Peak), number of repetitions, and psychological responses (affection: Feeling ScaleFS; Felt Arousal ScaleFAS; enjoyment: Physical Activity Enjoyment ScalePACES) were assessed. FRI and SSRI elicited similar relative average intensity (p > .05) (%HRmax: 88.1 ± 3.5% vs. 87.6 ± 3.0%; %VO2Peak: 55.3 ± 7.4% vs. 54.1 ± 8.1%, respectively). The number of repetitions similarly decreased in SSRI and FRI from rounds 1 to 4 (~15%; p < .006), with no difference of total volume across conditions (FRI: 358.6 ± 32 reps vs. SSRI:357.5 ± 28.2; p = .89). In each round, no difference between FRI and SSRI (p > .05) was found for FS (3- to 3.5 vs. 2- to 4, respectively) or FAS (2- to 4 vs. 2- to 4, respectively), while PACES was lower in FRI than SSRI (102.8 ± 15.8 vs. 109.2 ± 13.2; p = .04). Conclusion: In conclusion, relative intensity, total repetitions, and affective perception were not influenced by the strategy of recovery intervals. On the other hand, overall enjoyment was favored in SSRI vs. FRI.

Effects of exercise intensity on gut microbiome composition and function in people with type 2 diabetes

ABSTRACT Exercise is positively associated with higher microbial diversity, but there is limited information on exercise intensity's effect on gut microbiome composition and function in clinical populations. This study examines whether different intensities of exercise exert differential effects on gut microbiome composition and function in low active people with type 2 diabetes. This is a sub-study of the Exercise for Type 2 Diabetes Study, a single centre, prospective, randomised controlled trial. Participants (n = 12) completed 8-weeks of combined aerobic and resistance moderate intensity continuous training (C-MICT) or combined aerobic and resistance high-intensity interval training (C-HIIT). Faecal samples were collected before and after intervention to measure gut microbiome composition and metabolic pathways (metagenome shotgun sequencing) and short-chain fatty acids. Post-exercise α-diversity was different between groups as was the relative abundance of specific taxa was (p < .05). Post-exercise relative abundance of Bifidobacterium, A. municiphila, and butyrate-producers Lachnospira eligens, Enterococcus spp., and Clostridium Cluster IV were higher at lower exercise intensity. Other butyrate-producers (from Eryspelothrichales and Oscillospirales), and methane producer Methanobrevibacter smithii were higher at higher exercise intensity. Pyruvate metabolism (ko00620),COG “Cell wall membrane envelope biogenesis” and “Unknown function” pathways were significantly different between groups and higher in C-MICT post-exercise. Differential abundance analysis on KO showed higher expression of Two-component system in C-HIIT. Transcription factors and “unknown metabolism” related pathways decreased in both groups. There were no significant between group changes in faecal short chain fatty acids. Exercise intensity had a distinct effect on gut microbiome abundance and metabolic function, without impacting short-chain fatty acid output. Highlights Evidence of exercise effect on gut microbiome outcomes is limited to healthy and athletic populations In low active people with type 2 diabetes, different exercise intensities increased specific health promoting and butyrate producers species, and showed differentially abundant gut microbiome metabolic pathways. Further investigation is warranted, and if this supports the present findings, then specific exercise intensities may be promoted to target specific species and optimise gut health.

High-intensity interval resistance training (HIIRT) improves liver gluconeogenesis from lactate in Swiss mice.

High-intensity physical exercise favors anaerobic glycolysis and increases lactatemia. Lactate is converted back to glucose in the liver, so that the lactate threshold, an indicator of physical performance, must be related to the gluconeogenic capacity of the liver. This research assessed the effect of a high-intensity interval resistance training (HIIRT) on liver gluconeogenesis from lactate. Swiss mice were trained (groups T) on vertical ladder with overload of 90% of their maximal load. Control animals remained untrained (groups C0 and C8). In situ liver perfusion with lactate and adrenaline was performed in rested mice after 6 hours of food deprivation. There were larger outputs of glucose (T6, 71.90%; T8, 54.53%) and pyruvate (T8, 129.28%) (representative values for 4 mM lactate) in the groups trained for 6 or 8 weeks (T6 and T8), and of glucose in the presence of adrenaline in group T8 (280%). The content of PEPCK, an important regulatory enzyme of the gluconeogenic pathway, was 69.13% higher in group T8 than in the age-matched untrained animals (C8). HIIRT augmented liver gluconeogenesis from lactate and this might improve the lactate threshold. Novelty: The liver metabolizes lactate from muscle into glucose. Physical training may enhance the gluconeogenic capacity of the liver. As lactate clearance by the liver improves, lactate threshold is displaced to higher exercise intensities.

Exercise Intensity and Rest Intervals Effects on Intracellular Signals and Anabolic Response of Skeletal Muscle to Resistance Training

Moro, T, Monaco, L, Naro, F, Reggiani, C, and Paoli, A. Exercise intensity and rest intervals effects on intracellular signals and anabolic response of skeletal muscle to resistance training. J Strength Cond Res XX(X): 000–000, 2021—Resistance training (RT) is one of the most important stimuli for muscle hypertrophy, and it may play also an important role on weight loss and fatty acids oxidation. Clearly, RT affects anabolic pathways, but the differences among various training techniques has been poorly investigated. We sought to compare the effect of 2 different intensities of training: high-intensity interval resistance training (HIIRT) and traditional resistance training (TRT), on muscle signaling pathway. Nine young healthy subjects performed HIIRT and TRT protocol on 2 different occasions and with different legs on leg extension. High-intensity interval resistance training technique consisted of 3 sets of 6 repetitions (reps) at 6 repetition maximum and then 20 seconds of rest and 2 or 3 repetitions (until exhaustion) repeated for 3 times with 2′30″ rest between sets, whereas TRT consisted of 3 sets of 15 reps with 75 seconds of rest between sets. Biopsies from the vastus lateralis were taken at baseline (pre), immediately (0 hours) at the end of training, and 6 hours (6 h) and 24 hours (24 h) after training. Western blot and real-time polymerase chain reaction messenger RNA (mRNA) analysis were performed to assess muscle signaling pathway activation. In both protocols, rpS6 phosphorylation significantly increased at 6 hours (p < 0.05). Traditional resistance training showed a significant increase at 24 hours of AMPK phosphorylation compared with HIIRT (p < 0.05), whereas no significant differences between groups were found for other proteins. mRNA analysis showed no differences between protocols except for striated muscle activator of Rho signaling. The manipulation of resistance training intensity through incomplete/short recovery does not induce different molecular anabolic and metabolic responses compared with a TRT method. Trial Registration number: NCT04163120 retrospectively registered.

Effect of High-Intensity Interval Resistance Training on Appendicular Skeletal Muscle Mass Index Measured by Bioelectric Impedance Analysis in Sarcopenic Elderly Women

Background: Aging is an inevitable physiological process leading to a progressive decrease in muscle mass and function, which is called sarcopenia. Correspondingly, this study aimed to investigate the effect of High-Intensity Interval Resistance Training (HIIRT) on certain sarcopenia-related factors in elderly women. Methods: This was a quasi-experimental study in which thirty elderly women aged 60 to 70 years, from April to September 2020, volunteered to participate and were randomly assigned to the experimental (n=15) and control (n=15) groups. Body Mass Index (BMI), Appendicular Skeletal Muscle Mass (ASM), Appendicular Skeletal Muscle Mass Index (ASMI), and body fat percentage were measured using bioelectric impedance analysis; handgrip strength was measured via Jamar dynamometer; walking speed was measured employing six-meter walking test (6MWT); IGF-1 level (μg/L) was measured with Mediagnost kit (Germany) and serum myostatin level (ng/L) was measured using ELISA kit from R&D Company (USA) via Enzyme-Linked Immuno Sorbent Assay )ELISA( method in two stages: pre-test (week 0) and post-test (end of week 8). Independent t-test was subsequently utilized to assess the research variables through SPSS software version 23 at 0.05 level of significance. Results: The results indicated a significant decrease in body fat percentage (1.05±0.79, p <0.001) and Myostatin (MSTN) (87.25±82.38, p <0.01) and a significant increase in handgrip strength (-08.58±4.50, p <0.001), ASM (-4.91±0.28, p <0.001), ASMI (-0.19±0.11, p <0.001), and 6MWT (-0.42±0.26, p <0.001) in the experimental group compared to the control. There was also an increase in IGF-1 (-0.83±2.90, P=0.88), yet it was not significant. Conclusion: The major components indicative of sarcopenia were improved through High-Intensity Interval Resistance Training. Therefore, HIIRT appeared to be one of the most important coping strategies for reduction of muscle mass and strength in older women. We could thus conclude that it is necessary for the elderly to do this type of training.

Effects of 6 Weeks of Traditional Resistance Training or High Intensity Interval Resistance Training on Body Composition, Aerobic Power and Strength in Healthy Young Subjects: A Randomized Parallel Trial.

Consistent practice of physical activity has well known positive effects on general health; however, time for exercise remains one major barrier for many. An acute bout of high intensity interval resistance training (HIIRT) increases acute resting energy expenditure (REE) and decreases respiratory ratio (RR), suggesting its potential role on weight loss and increased fatty acid oxidation. The aim of this study was to test the long-term effect of HIIRT on body composition, lipid profile and muscle strength using a randomized parallel trial. Twenty healthy young adults (22.15 ± 1.95 years) were randomized to perform either a HIIRT (N = 11) protocol, consisting of three sets of 6 repetitions at 6 repetition maximum (RM) and then 20 seconds of rest between repetitions until exhaustion repeated for 3 times with 2′30″ rest between sets or a traditional training (TRT, N = 9) protocol of 3 sets of 15 reps with 75 sec of rest between sets. Body composition, resting energy metabolism, aerobic capacity, muscle strength and blood measurements were taken before and after 8 weeks of training. Both protocols enhanced muscle strength, but only HIIRT improved endurance strength performance (+22.07%, p < 0.05) and lean body mass (+2.82%, p < 0.05). REE and RR were unaltered as lipid profile. HIIRT represents a valid training method to improve muscle strength and mass, but its role on body weight control was not confirmed.

Resistance High-Intensity Interval Training (HIIT) Improves Acute Gluconeogenesis from Lactate in Mice

High-intensity interval training (HIIT) markedly activates muscle anaerobic glycolysis and increases blood lactate. As the liver is a major organ for lactate clearance from the bloodstream, it might improve gluconeogenesis from lactate (NEO-lac) after a period of resistance HIIT. NEO-lac was evaluated by <i>in situ</i> liver perfusion in mice subjected to a resistance HIIT for 4 (T4) or 8 (T8) weeks, or not trained (T0). Perfusion was carried out immediately after an incremental exercise session to test the acute NEO-lac. Muscle strength (expressed as relative maximum load) and blood lactate were higher in T4 than in T0, but NEO-lac did not differ, possibly because of energy discharge of the liver and substrate overload. After 8 weeks of HIIT (T8), both muscle strength and liver NEO-lac increased, but blood lactate did not. The resistance HIIT for 8 weeks modulated liver gluconeogenic efficiency and capacity, which are important mechanisms for the improved clearance of blood lactate.

High intensity resistance training causes muscle damage and increases biomarkers of acute kidney injury in healthy individuals.

PurposeHigh-intensity interval resistance training (HIIRT) is an increasingly popular exercise program that provides positive results with short sessions. This study aimed to evaluate whether an HIIRT session causes muscle and kidney damage.MethodsFifty-eight healthy volunteers (median age 24 years, 50% women) participated in this study and performed a HIIRT session. The Borg CR10 scale for pain (CR10P) and blood and urine samples were collected before (baseline) and 2 and 24 hours after the HIIRT session. Blood samples were analyzed for serum creatinine (SCr), creatine kinase (CK) and myoglobin. Urine samples were assessed for creatinine, neutrophil gelatinase-associated lipocalin, interleukin 18, calbindin, microalbuminuria, trefoil factor-3 and β-2 microglobulin.ResultsCR10P had a significant increase at 2 and 24 hours post-workout, and CK increased significantly at 2 hours and increased further at 24 hours. Myoglobin increased significantly at 2 hours and remained elevated at 24 hours. SCr increased modestly but significantly at 24 hours only in men. Three men met the KDIGO diagnostic criteria for acute kidney injury. The urinary kidney injury biomarkers increased significantly at 2 hours and returned to the baseline values 24 hours after HIIRT.ConclusionsA single HIIRT session caused early and significant elevations in CK, myoglobin, SCr, microalbuminuria and urinary biomarkers indicative of kidney tubular injury, suggesting the occurrence of muscle and kidney damage.

Effects on Insulin Sensitivity, but Not on Mitochondrial Function Are Dependent on Insulin Resistance Status after High Intensity Interval Training

High intensity interval training (HIIT) is a time-efficient training approach to stimulate biogenesis in healthy populations. We hypothesized that HIIT would increase skeletal muscle insulin sensitivity due to improved muscle mitochondrial function in type 2 diabetes (T2D) patients and age- and BMI-matched controls (CON). We examined 18 sedentary male patients with T2D and 23 healthy male CON (age: 58±5 vs. 57±4 years, BMI: 31.4±2.4 vs. 30.4±2.3 kg.m-2) that were enrolled in a 12-week HIIT cycling protocol. CON were further grouped in insulin-sensitive (IS) and -resistant (IR) (baseline M in mg.kg-1.min-1; 7.4 ± 1.3 vs. 4.2 ± 1.1, p&amp;lt;0.001). Two-step hyperinsulinemic-euglycemic clamps, skeletal muscle biopsies for high resolution respirometry and magnetic resonance spectroscopy for liver fat quantification were performed. After 12 weeks of HIIT, T2D and IR CON increased their insulin sensitivity (3.9±1.9 vs. baseline: 2.7±1.6, p=0.02 and 5.5±2.1 vs. 4.2 ± 1.1, p=0.03, respectively), which returned to baseline after detraining. T2D and IR CON increased suppression of endogenous glucose production (EGP) during the high-insulin clamp (T2D: 91 ± 14% vs. baseline: 76 ± 11%, p=0.003 and IR CON: 107 ± 13% vs. 94 ± 14%, p=0.04). IR CON also increased suppression of lipolysis during the low-insulin clamp (82 ± 9 vs. 84 ± 8%, p=0.04). In T2D liver fat was decreased by 17% and remained decreased after detraining. Liver fat content remained unchanged by HIIT training in both CON groups. Muscle maximal uncoupled respiration increased in T2D and CON by 44% and 48%, respectively, at 12 weeks and remained increased after detraining in all groups (p&amp;lt;0.01). We conclude that at the same level of insulin resistance HIIT training improved hepatic and peripheral insulin sensitivity in patients with T2D and insulin resistant controls whereas changes in mitochondrial function occurred irrespective of insulin resistance status. Disclosure M. Apostolopoulou: None. D. Pesta: None. Y. Karusheva: None. S. Gancheva: None. T. Jelenik: None. A. Bierwagen: None. K. M ssig: None. J. Szendroedi: None. M. Roden: Speaker's Bureau; Self; Boehringer Ingelheim GmbH. Research Support; Self; Boehringer Ingelheim GmbH. Consultant; Self; Poxel SA. Research Support; Self; Danone Nutricia Early Life Nutrition, GlaxoSmithKline plc., Nutricia Advanced Medical Nutrition, Sanofi.

High intensity interval resistance training (HIIRT) in older adults: Effects on body composition, strength, anabolic hormones and blood lipids

• High intensity interval resistance training (HIIRT) can be safely performed by older individuals. • HIIRT could reduce basal insulin, total cholesterol , LDL and TGs levels. • HIIRT could help to maintain lean body mass in older adults.

High-Intensity Interval Resistance Training (HIRT) influences resting energy expenditure and respiratory ratio in non-dieting individuals

BackgroundThe benefits of exercise are well established but one major barrier for many is time. It has been proposed that short period resistance training (RT) could play a role in weight control by increasing resting energy expenditure (REE) but the effects of different kinds of RT has not been widely reported.MethodsWe tested the acute effects of high-intensity interval resistance training (HIRT) vs. traditional resistance training (TT) on REE and respiratory ratio (RR) at 22 hours post-exercise. In two separate sessions, seventeen trained males carried out HIRT and TT protocols. The HIRT technique consists of: 6 repetitions, 20 seconds rest, 2/3 repetitions, 20 secs rest, 2/3 repetitions with 2′30″ rest between sets, three exercises for a total of 7 sets. TT consisted of eight exercises of 4 sets of 8–12 repetitions with one/two minutes rest with a total amount of 32 sets. We measured basal REE and RR (TT0 and HIRT0) and 22 hours after the training session (TT22 and HIRT22).ResultsHIRT showed a greater significant increase (p < 0.001) in REE at 22 hours compared to TT (HIRT22 2362 ± 118 Kcal/d vs TT22 1999 ± 88 Kcal/d). RR at HIRT22 was significantly lower (0.798 ± 0.010) compared to both HIRT0 (0.827 ± 0.006) and TT22 (0.822 ± 0.008).ConclusionsOur data suggest that shorter HIRT sessions may increase REE after exercise to a greater extent than TT and may reduce RR hence improving fat oxidation. The shorter exercise time commitment may help to reduce one major barrier to exercise.