Comparison of the Effect of Concurrent Moderate-Intensity Continuous Training and High-Intensity Interval Training with High-Intensity Interval Training Alone on Body Composition, Cortisol and Mental Health of Overweight 16-19-Year-old Male Students

High-intensity interval training (HIIT) has become popular, time-sparing alternative to moderate intensity continuous training (MICT), although the cardiac vascular and metabolic effects of HIIT are incompletely known. We compared the effects of 2-week interventions with HIIT and MICT on myocardial perfusion and free fatty acid and glucose uptake. Insulin-stimulated myocardial glucose uptake was decreased by training without any significantly different response between the groups, whereas free fatty acid uptake remained unchanged. Adenosine-stimulated myocardial perfusion responded differently to the training modes (change in mean HIIT: -19%; MICT: +9%; P=0.03 for interaction) and was correlated with myocardial glucose uptake for the entire dataset and especially after HIIT training. HIIT and MICT induce similar metabolic and functional changes in the heart, although myocardial vascular hyperaemic reactivity is impaired after HIIT, and this should be considered when prescribing very intense HIIT for previously untrained subjects. High-intensity interval training (HIIT) is a time-efficient way of obtaining the health benefits of exercise, although the cardiac effects of this training mode are incompletely known. We compared the effects of short-term HIIT and moderate intensity continuous training (MICT) interventions on myocardial perfusion and metabolism and cardiac function in healthy, sedentary, middle-aged men. Twenty-eight healthy, middle-aged men were randomized to either HIIT or MICT groups (n=14 in both) and underwent six cycle ergometer training sessions within 2weeks (HIIT session: 4-6×30s all-out cycling/4min recovery, MICT session 40-60min at 60% V̇O2 peak ). Cardiac magnetic resonance imaging (CMRI) was performed to measure cardiac structure and function and positron emission tomography was used to measure myocardial perfusion at baseline and during adenosine stimulation, insulin-stimulated glucose uptake (MGU) and fasting free fatty acid uptake (MFFAU). End-diastolic and end-systolic volumes increased and ejection fraction slightly decreased with both training modes, although no other changes in CMRI were observed. MFFAU and basal myocardial perfusion remained unchanged. MGU was decreased by training (HIIT from 46.5 to 35.9; MICT from 47.4 to 44.4mmol100g-1 min-1 , P=0.007 for time, P=0.11 for group×time). Adenosine-stimulated myocardial perfusion responded differently to the training modes (change in mean HIIT: -19%; MICT: +9%; P=0.03 for group×time interaction). HIIT and MICT induce similar metabolic and functional changes in the heart, although myocardial vascular hyperaemic reactivity is impaired after HIIT. This should be taken into account when prescribing very intense HIIT for previously untrained subjects.

High Intensity Interval Training in Patients With Cardiovascular Disease: A Brief Review of Physiologic Adaptations and Suggestions for Future Research

Comparison of the effects of high-intensity interval and moderate-intensity continuous training on inflammatory markers, cardiorespiratory fitness, and quality of life in breast cancer patients

To test the effectiveness on recreational female middle-aged runners of a programme of high-intensity interval training (HIIT) for a half-marathon race contrasted to a conventional moderate-intensity continuous training (MICT). Twenty recreational female runners (40 ± 7years) followed MICT or HIIT schedules for training a half-marathon. The MICT group trained a mean of 32km/week at intensities below 80% VO2max. The HIIT group ran 25km/week at intensities between 80 and 100% VO2max, combined with uphill running and resistance training. Women following HIIT ran 21% less distance and invested 17% less time than those from MICT group. All the women were evaluated at the beginning and end of the training and participated in the same half-marathon run. Women following both schedules reduced their previous finishing times by 2-3%, which for HIIT group would have meant rising up to 90 positions out of 1454 participants in the local half-marathon race. The high intensity performed during series of high power output (200m and 400m) and resistance sessions in HIIT programme promoted changes that allowed modifying efficiency at high workloads. At the same time, the HIIT training programme elicited changes in oxygen uptake and transport as indicated the cardiorespiratory parameters obtained during recovery in lab tests. Moreover, HIIT registered a 14% baseline decrease in heart rate contrasting to the not significant 6% decrease in MICT. Runners following HIIT training obtained similar registers as with a traditional MICT schedule, expending less time and running shorter distances, yet improving their anaerobic and aerobic power.

Cardiac rehabilitation (CR) is essential in reducing cardiovascular mortality and morbidity. High-intensity interval training (HIIT) has emerged as a promising exercise intervention for enhancing clinical outcomes in cardiac patients. This study aimed to investigate the effects of two short-term exercise-based programs employing HIIT and moderate-intensity continuous training (MICT) in comparison to a control group concerning blood pressure, body composition, and blood biomarkers in patients diagnosed with coronary artery disease (CAD). Seventy-two CAD patients (14% women) underwent randomization into three groups: HIIT, MICT, and control. The training programs encompassed six weeks of supervised treadmill exercises, conducted thrice weekly. MICT targeted 70-75% of peak heart rate (HRpeak), while HIIT was tailored to 85-95% of HRpeak. The control group received guidance on adopting healthy lifestyles. Outcome measurements included evaluations of blood pressure, body composition, and blood biomarkers. In contrast to MICT, the HIIT exhibited superior improvements in body fat mass ( %HIIT: 4.5%, p 0.001 vs. %MICT: 3.2%, p 0.001), waist circumference ( %HIIT: 4.1%, p = 0.002 vs. %MICT: 2.5%, p = 0.002), hemoglobin A1c (HbA1c) ( %HIIT: 10.4%, p 0.001 vs. %MICT: 32.3%, p 0.001) and thyrotropin (TSH) ( %HIIT: 16.5%, p = 0.007 vs. %MICT: 3.1%, p = 0.201). Both HIIT and MICT induced significant enhancements across all variables compared to the control group. HIIT and MICT emerged as effective modalities for enhancing systolic and diastolic function, body composition, and blood biomarkers in CAD patients, with HIIT demonstrating incremental improvements over MICT. The absence of participation in exercise-based programs following cardiovascular events yielded less favorable outcomes. HIIT holds promise as an adjunct intervention in CR programs for CAD patients. https://clinicaltrials.gov/ct2/show/NCT03538119.

PURPOSE: The objective of the present study was to investigate the effects of 8-week high-intensity interval training (HIIT) on bone metabolism in sedentary college women. METHODS: Twenty-six healthy, sedentary female participants were randomly assigned into either HIIT (n = 13, age 23.2 ± 2.9 yr, weight 59.2 ± 7.2 kg, height 162.9 ± 3.3 cm; 90% VO2max run for 3 min interspersed with 40% VO2max run for 2 min, 6 bouts in one session) or moderate-intensity continuous training (MICT) group (n = 13, age 21.9 ± 1.7 yr, weight 59.3 ± 6.6 kg, height 160.9 ± 4.4 cm; 60% VO2max continuous run for 30 min) with 3 sessions per week for 8 weeks. The bone mineral density (BMD), quantitative ultrasound of the calcaneus (CUS), serum bone turnover markers, jump abilities and body composition were measured pre and post HIIT and MICT interventions. RESULTS: After 8-week interventions, 1) The total body BMD (pre vs post: 0.94 ± 0.05 vs 1.01 ± 0.05, p < 0.01 in HIIT; 0.95 ± 0.05 vs 1.00 ± 0.05 g/cm2, p < 0.01 in MICT), lower limb BMD (1.01 ± 0.08 vs 1.06 ± 0.06, p < 0.01 in HIIT; 1.00 ± 0.08 vs 1.04 ± 0.10 g/cm2, p < 0.01 in MICT), pyridinoline (PYD) (29.93 ± 7.00 vs 25.42 ± 6.79, p < 0.01 in HIIT; 31.64 ± 6.22 vs 25.13 ± 5.39 nmol/L, p < 0.01 in MICT) and %body fat (31.43 ± 5.65 vs 28.85 ± 5.52, p < 0.01 in HIIT; 33.15 ± 4.48 vs 31.48 ± 4.73, p < 0.05 in MICT) were significantly changed without differences between two groups. 2) The 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) (12.10 ± 2.59 vs 17.19 ± 3.44, p < 0.01 in HIIT; 12.08 ± 2.11 vs 14.80 ± 2.01 ug/L, p < 0.01 in MICT), standing long jump (1.61 ± 0.78 vs 1.77 ± 0.83, p < 0.01 in HIIT; 1.59 ± 0.13 vs 1.65 ± 0.14 m, p < 0.01 in MICT) and vertical jump (2.30 ± 0.05 vs 2.42 ± 0.05, p < 0.01 in HIIT; 2.33 ± 0.04 vs 2.37 ± 0.04 m, p < 0.01 in MICT) were increased in both groups with significantly higher changes in HIIT group (p < 0.05). 3) The calcaneus stiffness index (CSTI) (108.77 ± 10.47 vs 126.38 ± 11.92 %, p < 0.01 in HIIT), calcaneus broadband ultrasound attenuation (CBUA) (121.70 ± 9.47 vs 140.40 ± 9.17 dB/MHz, p < 0.01 in HIIT) and osteocalcin (OC) only significantly increased after HIIT intervention (p < 0.01). CONCLUSIONS: It suggested that 8-week HIIT and MICT intervention could improve BMD and body composition. Compared with similar workload MICT, HIIT elicited superior benefits on bone formation and related jump abilities.

Soccer performance is the result of technical, tactical, physiological and psychological attributes of the players. PURPOSE: The present study investigated the effect of high- intensity interval training (HIIT) and continuous moderate intensity training (CONT) on selected parameters of the cardiorespiratory function in young trained soccer players. METHODS: Thirty Greek amateur soccer players (mean ± sd, age 19 ± 2,21y, Body mass 71.19 ± 2.5 kg) were randomized into a high-intensity interval training group (HIIT, n = 10), a continuous moderate intensity training group (CONT, n = 10) and a control group (Control, n = 10). The intervention for HIIT and CONT groups was 16 more training sessions, 2 per week while CONTROL group continued regular soccer training routine. The HIIT group training sessions consisted either of 15s sprints interspersed by 15s of recovery at 120%VO2max with 8 min total exercise time or they played 4x4 min (16 min total time) small-sided games (4v4) followed by 2 min recovery interval. The CONT group training sessions consisted either of 40 min continuous running at 70% VO2max or 10v10 full field soccer game for 40min. RESULTS: Mean values ± sd pre and post-training for Body weight, (HIIT: 69.49 ± 8.39 v 69.0 ± 8.8; CONT: 71.2 ± 10.93 v 70.2 ± 11.01 kg), %fat, (HIIT: 13.02 ± 2.41 v 12.12 ± 2.49, CONT: 13.75 ± 2.19 v 13.82 ± 2.21), VO2max, (HIIT: 55.08 ± 4.43 v 57.75 ± 5.63, CONT: 56.46 ± 4.61 v 58.41 ± 5.24 ml.kg-1.min-1), vVO2max (velocity at VO2max, HIIT: 15.9 ± 0.70 v 16.5 ± 0.52, CONT: 16.5 ± 1.51 v 16.7 ± 1.19 km.h-1) and vVT (velocity at ventilatory threshold, HIIT: 11.8 ± 0.87 v 12.5 ± 0.69, CONT: 12.4 ± 1.03 v 12.5 ± 1.13 km.h-1). VO max, vVO2max and vVT improved 4.6, 3.6 and 5.6% only after HIIT training but the difference didn’t pass statistical significance due to large sd of the sample. CONCLUSIONS: In conclusion, the combination of the training regiments of this study did not improve cardiorespiratory parameters of endurance performance in already trained young soccer players. There was, though, a tendency for better adaptations favors the time efficient HIIT training.

There is no consensus on how, when, or at what intensity exercise should be performed after heart transplantation (HTx). We have recently shown that high-intensity interval training (HIT) is safe, well tolerated, and efficacious in the maintenance state after HTx, but studies have not investigated HIT effects in the de novo HTx state. We hypothesized that HIT could be introduced early after HTx and that it could lead to clinically meaningful increases in exercise capacity and health-related quality of life. This multicenter, prospective, randomized, controlled trial included 81 patients a mean of 11 weeks (range, 7-16 weeks) after an HTx. Patients were randomized 1:1 to 9 months of either HIT (4×4-minute intervals at 85%-95% of peak effort) or moderate-intensity continuous training (60%-80% of peak effort). The primary outcome was the effect of HIT versus moderate-intensity continuous training on the change in aerobic exercise capacity, assessed as the peak oxygen consumption (Vo2peak). Secondary outcomes included tolerability, safety, adverse events, isokinetic muscular strength, body composition, health-related quality of life, left ventricular function, hemodynamics, endothelial function, and biomarkers. From baseline to follow-up, 96% of patients completed the study. There were no serious exercise-related adverse events. The population comprised 73% men, and the mean±SD age was 49±13 years. At the 1-year follow-up, the HIT group demonstrated greater improvements than the moderate-intensity continuous training group; the groups showed significantly different changes in the Vo2peak (mean difference between groups, 1.8 mL·kg-1·min-1), the anaerobic threshold (0.28 L/min), the peak expiratory flow (11%), and the extensor muscle exercise capacity (464 J). The 1.8-mL·kg-1·min-1 difference was equal to ≈0.5 metabolic equivalents, which is regarded as clinically meaningful and relevant. Health-related quality of life was similar between the groups, as indicated by results from the Short Form-36 (version 2), Hospital Anxiety and Depression Scale, and a visual analog scale. We demonstrated that HIT was a safe, efficient exercise method in de novo HTx recipients. HIT, compared with moderate-intensity continuous training, resulted in a clinically significantly greater change in exercise capacity based on the Vo2peak values (25% versus 15%), anaerobic threshold, peak expiratory flow, and muscular exercise capacity. URL: https://www.clinicaltrials.gov . Unique identifier NCT01796379.

Background/Objectives: Our study aimed to verify the effects of 6 weeks of concurrent training composed of resistance training (RT) and different modalities of aerobic exercise (moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT)) on body composition, blood pressure, vascular function, autonomic nervous system (ANS) function, blood lipid levels, cardiometabolic index (CMI), and health-related fitness in obese middle-aged women with prehypertension. Methods: We selected 26 middle-aged women with obesity and prehypertension and divided them equally into the RT + MICT (n = 13) and RT + HIIT (n = 13) groups. The concurrent training program consisted of warm-up, RT, aerobic exercise (MICT or HIIT), and cool-down, and was performed for 6 weeks, three times a week, 85-100 min per session. The measured dependent parameters were analyzed before and after training. Results: Concurrent training (RT + MICT and RT + HIIT) for 6 weeks showed significant improvements in body composition, blood pressure, vascular function, ANS function, CMI, and health-related fitness. However, the RT + HIIT group showed a relatively greater improvement in blood lipid levels compared to the RT + MICT group. Conclusions: Our study confirmed that both RT + MICT and RT + HIIT yielded similar positive effects on most health-related parameters in obese middle-aged women with prehypertension. Among them, RT + HIIT appeared to be relatively more effective in improving blood lipid profiles.

Introduction:Growing research suggests that aerobic high-intensity interval training (HIIT) improves cardiovascular function and physical performance compared with moderate intensity continuous training (MICT). However relatively few animal models of HIIT are available to inform about the benefits of this exercise—particularly among older animals. In addition, there is little evidence for how HIIT training interacts with adjuvant pharmacological therapies known to enhance the impact of MCIT in older individuals such as Angiotensin Converting Enzyme (ACE) Inhibitors.Purpose:The aim of the present study was to establish a HIIT protocol in aged rats based on forced running wheel-bed, and to subsequently (1) establish the feasibility of the HIIT protocol in a proof-of-concept study evaluating interactions between HIIT and (2) the result of combining HIIT + ACE inhibitor treatment using the ACE inhibitor enalapril.Methods:Two groups of rats were used in this study. The feasibility of using wheel-bed for HIIT training was tested in group one (15- and 30-month-old male rats). In the second group, 37 24-month-old Fisher 344 × Brown Norway male rats were randomly divided into four subgroups: control, enalapril, HIIT training group, and HIIT training combined with enalapril administration. The training and administration lasted for 4 weeks. After the intervention, locomotor activity, exercise tolerance, and grip strength were tested.Results:Our feasibility study suggested that middle-aged and aged rats were able to successfully complete the HIIT training. In our intervention study, HIIT training alone, regardless of adjuvant enalapril intervention, did raise treadmill exercise tolerance vs. the sedentary condition. Measures of healthspan were not negatively impacted by HIIT training.Conclusion:The novel HIIT protocol based on forced running wheel-bed was successfully employed in aged rats. We conclude that future studies should compare the results and of multi-modal intervention strategies which include both HIIT and MICT in combination with adjuvant therapies such as enalapril to improve exercise tolerance and other global indices of healthspan.

Simple SummaryWe conducted this study to see whether HIIT and MICT can significantly decrease inflammatory markers through improving body composition in BCS. As such, these practical studies have a high degree of utility for the readership of this journal since most cancer survivors are afraid to perform physical activities. Although HIIT and MICT are effective strategies for improving inflammation, body composition, and physical fitness in BCS, our findings suggest that HIIT is superior to MICT in attenuating TNF-α and leptin as well as improving BM, FM, and LBS.Background: Chronic inflammation associated with breast cancer (BC) poses a major challenge in care management and may be ameliorated by physical activity. This randomized controlled trial assessed the effects of a 12-week high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on inflammatory markers, body composition, and physical fitness in BC survivors (BCS). Methods: Forty BCS (age = 57 ± 1 years; body mass [BM] = 74.8 ± 1.5 kg; VO2peak = 20.8 ± 2.1 mL·kg−1·min−1) were randomly assigned to three groups: HIIT (n = 15), MICT (n = 15), or control (CON; n = 15). The intervention groups (HIIT and MICT) performed their respective exercise protocols on a cycle ergometer 3 days/week for 12 weeks while the CON group maintained their current lifestyle. Baseline and post-intervention assessments included body composition (BM, fat mass (FM), lean mass (LM)), physical fitness (VO2peak, lower body strength (LBS), upper body strength (UBS)), and serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), leptin, and adiponectin. Results: Both intervention groups significantly (p < 0.05) decreased BM (HIIT = −1.8 kg, MICT = −0.91 kg), FM (HIIT = −0.81 kg, MICT = −0.18 kg), TNF-α (HIIT = −1.84 pg/mL, MICT = −0.99 pg/mL), IL-6 (HIIT = −0.71 pg/mL, MICT = −0.36 pg/mL), leptin (HIIT = −0.35 pg/mL, MICT = −0.16 pg/mL) and increased VO2peak (HIIT = 0.95 mL·kg−1·min−1, MICT = 0.67 mL·kg−1·min−1), LBS (HIIT = 2.84 kg, MICT = 1.53 kg), UBS (HIIT = 0.53 kg, MICT = 0.53 kg), IL-10 (HIIT = 0.63 pg/mL, MICT = 0.38 pg/mL), and adiponectin (HIIT = 0.23 ng/mL, MICT = 0.1 ng/mL) compared to baseline. The changes in BM, FM, TNF-α, leptin, and LBS were significantly greater in HIIT compared to all other groups. Conclusions: Our findings indicate that compared to the often-recommended MICT, HIIT may be a more beneficial exercise therapy for the improvement of inflammation, body composition and LBS in BCS; and consequently, merits long-term study

New strategies are urgently needed to increase physical activity participation in the increasingly sedentary population to combat the rising rates of obesity and metabolic disease. The aim of this thesis was to provide evidence that practical high-intensity interval training (HIT) strategies can remove many of the major exercise barriers for obese individuals and people with type 1 diabetes that could potentially increase physical activity participation. Secondly, this thesis aimed to provide mechanistic evidence to explain the physiological effectiveness of HIT as a means to reduce the risk of cardio-metabolic disease. In Chapters 4 and 5, 32 obese adults with at least 3 additional cardiovascular disease (CVD) risk factors completed one of three 12-week training programmes 3x/week: Home-HIT (n=9); Laboratory-based supervised HIT (Lab-HIT; n=10) or home-based moderate intensity continuous training (Home-MICT; n=13). Changes in V O2peak, insulin sensitivity, body composition, flow-mediated dilation (FMD) and aortic pulse wave velocity (PWV) were assessed. Muscle biopsies were taken to assess changes in capillarisation, mitochondrial density, intramuscular triglyceride (IMTG) content and eNOS and GLUT4 protein expression using quantitative immunofluorescence microscopy. Adherence and compliance (Home-HIT 96±3% & 99±1%; Home-MICT 88±4% & 100±0%; Lab-HIT 97±1% & 100±0%, respectively) to training did not differ between groups. Training increased V O2peak and Matsuda insulin sensitivity index (P<0.05). BMI, body fat percentage and visceral fat decreased (P<0.05). FMD increased and aortic PWV decreased in each group (P<0.05). Immunofluorescence microscopy revealed increased capillarisation, mitochondrial density, IMTG content and eNOS and GLUT4 protein expression (P<0.05). In Chapter 6, 14 people with type 1 diabetes completed a randomised counterbalanced crossover design whereby continuous glucose monitoring was used to assess glycaemic control and risk of hypoglycaemia following a single bout of HIT and moderate-intensity continuous training (MICT) on separate days, compared to a non-exercise control day (CON). In Chapter 7, 14 people with type 1 diabetes (n=7 per group) completed six weeks of HIT or MICT 3x/week and the effect on glucose control and markers of cardio-metabolic health were measured. Chapter 6 showed no difference in the time, incidence or severity of hypoglycaemia over the 24-hour or nocturnal period between the CON, HIT and MICT days. In Chapter 7, six weeks of HIT or MICT improved V O2max by 14% and 15%, respectively and aortic PWV by 12%, with no difference between groups. Therefore, Chapters 6 and 7 demonstrate that HIT is an effective exercise strategy for people with type 1 diabetes that reduces the two major barriers of lack of time and fear of hypoglycaemia. Finally, in Chapter 8, eleven previously sedentary individuals with type 1 diabetes completed 6 weeks of Home-HIT. Blood glucose was monitored before, immediately and 1h after all of the exercise sessions. Perceptions of the program along with attitudes towards exercise, barriers to exercise and previous experiences of exercise were evaluated using an online survey. Training session adherence was 93±2%, with participants achieving their target HR in 99±1% of sessions. Blood glucose was not different from baseline immediately or 1h post HIT exercise. Training increased V O2peak by 8% (P=0.015), but blood pressure was unchanged (P=0.445). The qualitative data showed that the Home-HIT programme was positively received with many benefits. In conclusion, this thesis provides strong evidence that HIT can reduce major barriers to exercise and potentially increase exercise participation in these at-risk populations. Furthermore, Home-HIT was shown to be an effective strategy to improve a wide range of physiological markers indicative of improved cardio-metabolic health. Importantly, Home-HIT not only reduced traditional barriers to exercise, but also the key barrier in people with type 1 diabetes, fear of hypoglycaemia. As such, Home-HIT may represent an effective strategy to improve health in obese individuals with elevated CVD and people with type 1 diabetes by increasing exercise participation. Future research should investigate the effects of Home-HIT on a larger scale using larger cohorts and longer training periods using large-scale randomised controlled trials.

Objective: This study aimed to compare the effects of High-Intensity Interval Training (HIIT) and Moderate-Intensity Continuous Training (MICT) on glycemic control, beta-cell function, and aerobic fitness in women with Type 2 Diabetes Mellitus (T2DM). Methods: Thirty-six women with T2DM were assigned equally to HIIT, MICT, and control (CON) groups. Participants in the exercise cohorts underwent a 12-week training regimen (three sessions per week), while the CON group maintained an inactive lifestyle. Glycaemia variables, beta-cell function, maximal oxygen uptake (VO2max), lipid profiles, and body composition were assessed at baseline and post-intervention. Results: Both HIIT and MICT interventions led to significant improvements in glucose, insulin, HbA1c, and insulin resistance index. Moreover, visceral adiposity index (VAI), lipid accumulation product (LAP), total cholesterol (TC), and low-density lipoprotein (LDL) levels significantly decreased in the HIIT and MICT groups after 12 weeks. Triglyceride (TG) levels decreased only after MICT, while high-density lipoprotein (HDL) levels increased after both interventions. Maximal oxygen uptake (VO2max), body mass, body mass index (BMI), and waist circumference (WC) significantly improved in all exercise groups. Notably, the HIIT group showed greater reductions in body mass compared to MICT. Nevertheless, beta-cell function remained unaltered after these two exercise regimens. Conclusion: Both HIIT and MICT interventions effectively managed T2DM in women, regardless of exercise intensity. The HIIT regimen can be considered for time-efficient lifestyle interventions in people with T2DM.

Background: High-intensity interval training (HIIT) has been shown to improve cardiometabolic health during supervised lab-based studies but adherence, enjoyment, and health benefits of HIIT performed independently are yet to be understood. We compared adherence, enjoyment, and cardiometabolic outcomes after 8 weeks of HIIT or moderate-intensity continuous training (MICT), matched for energy expenditure, in overweight and obese young adults. Methods: 17 adults were randomized to HIIT or MICT. After completing 12 sessions of supervised training over 3 weeks, participants were asked to independently perform HIIT or MICT for 30 min, 4 times/week for 5 weeks. Cardiometabolic outcomes included cardiorespiratory fitness (VO2 peak), lipids, and inflammatory markers. Exercise enjoyment was measured by the validated Physical Activity Enjoyment Scale. Results: Exercise adherence (93.4 ± 3.1% vs. 93.1 ± 3.7%, respectively) and mean enjoyment across the intervention (100.1 ± 4.3 vs. 100.3 ± 4.4, respectively) were high, with no differences between HIIT and MICT (p > .05). Similarly, enjoyment levels did not change over time in either group (p > .05). After training, HIIT exhibited a greater decrease in low-density lipoprotein cholesterol than MICT (−0.66 mmol L−1 vs. −0.03 mmol L−1, respectively) and a greater increase in VO2 peak than MICT (p < .05, +2.6 mL kg min−1 vs. +0.4 mL kg min−1, respectively). Interleukin-6 and C-reactive protein increased in HIIT (+0.5 pg mL−1 and + 31.4 nmol L−1, respectively) and decreased in MICT (−0.6 pg mL−1 and −6.7 nmol L−1, respectively, p < .05). Conclusions: Our novel findings suggest that HIIT is enjoyable and has high unsupervised adherence rates in overweight and obese adults. However, HIIT may be associated with an increase in inflammation with short-term exercise in this population.

Background: The cardio-vascular diseases have an inflammatory background and systemic inflammation has the key role in the development of atherosclerosis and this factor may specially increase cardiovascular problems in overweight and obese people. The aim of this study was compares the effects of ten weeks High Intensity Interval (HIIT) training and moderate intensity aerobic training (MIAT) on some cardiovascular risk factors in overweight inactive men. Methods: Nineteen overweight men (with an average age of 24.12 ± 1.42 and body mass index 27.27 ± 0.94 kg / m2) voluntarily participated in this study and were randomly divided to 2 Groups: Group A (HIIT) and Group B (MIAT). Subjects performed training programs for 10 weeks, 3 sessions per week. The levels of C-reactive protein and lipid profile were measured before and after 10 weeks of training programs. For statistical data analysis, independent and paired t tests were used and considered significant at a p≤0.05. Results: After 12 weeks of High Intensity Interval training, levels of cholesterol (P=0.001), LDL (P=0.002) and CRP (P=0.001) were significantly reduced and HDL level increased significantly (P=0.001), In MIAT training group, only a significant reduction in cholesterol was found (P=0.006). Conclusion: The ten weeks HIIT training can cause favorable changes in body fat percentage, lipid profile and CRP level in overweight students.