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High-intensity interval training (HIIT) is effective for generating positive cardiovascular health and fitness benefits. This study compared HIIT and moderate-intensity continuous training (MICT) for affective state and enjoyment in sedentary males with overweight or obesity.Twenty-eight participants performed stationary cycling for 6 weeks × 3 sessions/week. Participants were randomly allocated to HIIT (N=16) (10 × 1-minute intervals at ~90% peak heart rate) or MICT (N=12) (30 minutes at 65-75% peak heart rate). Affective state changes were assessed after 6-weeks training. Enjoyment and acute change in affect were assessed after individual training sessions.HIIT participants reported improved positive affect following 6 weeks training (∆ 3.6 ± 4.6, p = 0.007, effect size d = 0.70), without corresponding improvement in negative affect (p = 0.48, d = -0.19). MICT did not induce any improvement in positive affect (p = 0.56, d = 0.16) or negative affect (p = 0.23, d = -0.41). Enjoyment ratings were comparable for both exercise formats (HIIT: 4.4 ± 0.4 on a 7-point scale; MICT: 4.3 ± 0.3; p = 0.70, d = 0.15).Six weeks of HIIT induced improvement in positive affect in sedentary participants with overweight or obesity. Enjoyment of training was only slightly above neutral levels for both training formats. What's already known about this topic? Exercise training can improve general affect however the optimal exercise characteristics for improving affect are unclear.Studies assessing the relative enjoyment of HIIT in comparison to MICT have largely been equivocal to date. What does this study add? HIIT can improve affective state in males with overweight or obesity.Six weeks of stationary cycling HIIT were rated as only mildly enjoyable, comparable to ratings for MICT.

Purpose: Cardiorespiratory fitness (CRF) is an independent predictor of mortality, and females typically achieve smaller improvements in CRF than males after exercise-based cardiac rehabilitation. High-intensity interval training (HIIT) has been shown to produce superior improvements in CRF than traditional cardiac rehabilitation, but the sex differences are unknown. The purpose of this systematic review and meta-analysis was to evaluate sex differences for changes in CRF and cardiometabolic health indicators after HIIT in adults with coronary artery disease (CAD)., Methods and Results: A systemic search of five electronic databases for studies examining the effect of HIIT on measured CRF and cardiometabolic health indicators in adults with CAD was performed. Data (published and unpublished) from 14 studies were included in the meta-analyses with approximately eightfold greater male than female participation (n = 836 vs n = 103). Males with CAD achieved a near-significant absolute improvement in CRF (mean difference [MD] = 1.07, 95% confidence interval [CI] = -0.08 to 2.23 mL·kg-1⋅min-1, P = 0.07) after HIIT when compared with control; there were insufficient data to conduct such an analysis in females. Significantly smaller improvements in CRF were experienced by females than males (MD = -1.10, 95% CI = -2.08 to -0.12 mL·kg-1⋅min-1, P = 0.03); there was no sex difference for the relative (percentage) change in CRF after HIIT. Females achieved significantly smaller reductions in body mass index (MD = -0.25, 95% CI = -0.03 to -0.47 kg·m-2, P = 0.02) and fasting blood glucose (MD = -0.38, 95% CI = -0.05 to -0.72, P = 0.03); no sex differences were observed for other cardiometabolic health indicators., Conclusion: There are no sex differences for relative improvements in CRF after HIIT; however, females are greatly underrepresented in trials. Future studies should increase female participation and perform sex-based analyses to determine sex-specific outcomes following HIIT., (Copyright © 2021 by the American College of Sports Medicine.)

The optimal exercise-training characteristics for reducing blood pressure (BP) are unclear. We investigated the effects of 6-weeks of high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) on BP and aortic stiffness in males with overweight or obesity. Twenty-eight participants (18-45 years; BMI: 25-35 kg/m 2 ) performed stationary cycling three times per week for 6 weeks. Participants were randomly allocated (unblinded) to work-matched HIIT (N = 16; 10 × 1-min intervals at 90-100% peak workload) or MICT (N = 12; 30 min at 65-75% peak heart rate). Central (aortic) and peripheral (brachial) BP and aortic stiffness was assessed before and after training. There were no significant group × time interactions for any BP measure (all p > 0.21). HIIT induced moderate reductions in central (systolic/diastolic ∆: -4.6/-3.5 mmHg, effect size d = -0.51/-0.40) and peripheral BP (-5.2/-4 mmHg, d = -0.45/-0.47). MICT induced moderate reductions in diastolic BP only (peripheral: -3.4 mmHg, d = -0.57; central: -3 mmHg, d = -0.50). The magnitude of improvement in BP was strongly negatively correlated with baseline BP (r = -0.66 to -0.78), with stronger correlations observed for HIIT (r = -0.73 to -0.88) compared with MICT (r = -0.43 to -0.61). HIIT was effective for reducing BP (~3-5 mmHg) in the overweight to obese cohort. Exercise training induced positive changes in central (aortic) BP. The BP-lowering effects of exercise training are more prominent in those with higher baseline BP, with stronger correlation in HIIT than MICT.

Background: The optimal characteristics of high-intensity interval training (HIIT) for patients with coronary artery disease (CAD) within cardiac rehabilitation (CR) are unclear. We assessed a HIIT protocol designed to balance patient safety, efficacy and enjoyment., Methods: Twenty-nine patients with CAD completed 6-weeks (× 2 sessions per week) of HIIT within outpatient (phase 2) CR. HIIT comprised 15 repetitions × 30-seconds cycling at ∼85-90% maximum heart rate, interspersed with 30-seconds of active recovery. Key outcomes covered patient safety, efficacy (peak aerobic capacity, body composition, blood pressure and vascular function), and patient adherence and enjoyment., Results: No cardiovascular-related adverse events were reported in relation to HIIT sessions. Patients showed significant improvement in peak aerobic capacity (mean +12%, p < 0.001, effect size d = 0.38), blood pressure (brachial systolic -7mmHg, p < 0.001, d = -0.59) and total body fat (-4%, p < 0.001, d = -0.49). Central adaptations were prominent (aortic systolic BP -5mmHg, p = 0.001, d = -0.50; visceral fat -10%, p = 0.001, d = -0.41). Patient enjoyment of training was high (5.5 out of 7 using the Exercise Enjoyment Scale) and measures of affective state improved following training (assorted p < 0.018)., Conclusions: This HIIT protocol appears safe, effective and enjoyable for patients with CAD within CR. Improved aerobic fitness, blood pressure and body fat levels were observed indicating improved cardiovascular-risk. High patient enjoyment and improved mood suggest the HIIT could be sustainable for patients in the longer-term., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background Cardiac rehabilitation ( CR ) for patients with cardiovascular disease has traditionally involved low- to moderate-intensity continuous aerobic exercise training ( MICT ). There is growing and robust evidence that high-intensity interval training ( HIIT ) shows similar or greater efficacy compared with MICT across a range of cardiovascular and metabolic measures, in both healthy populations and populations with a chronic illness. However, there is understandable concern about the safety aspects of applying HIIT in CR settings. This systematic review analyzed safety data drawn from recent proof-of-concept studies of HIIT during CR among patients with cardiovascular disease. Methods and Results We included trials comparing HIIT with either MICT or usual care in patients with coronary artery disease or heart failure participating in tertiary care services, such as phase 2 (outpatient) CR . Adverse events occurring during or up to 4 hours after an exercise training session were collated. There were 23 studies included, which analyzed 1117 participants ( HIIT =547; MICT =570). One major cardiovascular adverse event occurred in relation to an HIIT session, equating to 1 major cardiovascular event per 17 083 training sessions (11 333 training hours). One minor cardiovascular adverse events and 3 noncardiovascular adverse events (primarily musculoskeletal complaints) were also reported for HIIT . Two noncardiovascular events were reported in relation to MICT . Conclusions HIIT has shown a relatively low rate of major adverse cardiovascular events for patients with coronary artery disease or heart failure when applied within CR settings.

BACKGROUND: Moderate-intensity interval training (MIIT) may be a viable exercise format for improving body composition, aerobic fitness, and health-related variables. OBJECTIVES: This randomized trial aimed to analyze the effect of MIIT or high-intensity interval training (HIIT) on aerobic fitness, body composition variables, and resting metabolic rate (RMR) in women with overweight or obesity. METHODS: 31 sedentary adult women with overweight or obesity performed 7 weeks × 3 weekly sessions of either HIIT or MIIT. Physical and physiological tests were applied before and after training. RESULTS: In both analyses (intention-to-treat and by adherence to the training), aerobic fitness showed a time effect (p = 0.041 and p = 0.015), but without differences between groups (p > 0.05). No group (HIIT vs. MIIT), time (pre vs. post), or interaction effects (group vs. time) were found for RMR, body composition markers (fat mass, body fat percentage, lean mass), or body mass index – BMI (p > 0.05). In addition, MIIT induced a relatively high drop-out rate. CONCLUSIONS: This study suggested that the short-term (7-weeks) interval exercise training was effective for increasing aerobic fitness, and moderate-intensity intervals were as effective as high-intensity intervals. However, neither training format was effective for changing RMR, body composition variables, or BMI of women with overweight or obesity. Clinical trial ID: RBR-9jd7b7. [ABSTRACT FROM AUTHOR]