Body composition, cardiorespiratory fitness, and neuromuscular adaptations induced by a home-based whole-body high intensity interval training.

Background/objective: Bodyweight exercises performed at home could be a complementary approach to improve health-related fitness in people having little spare time and during stay-at-home periods. This study then investigated body composition, cardiorespiratory fitness, and neuromuscular adaptations to a home-based, video-directed, whole-body high-intensity interval training (WB-HIIT). Methods: Fourteen subjects participated to an 8-week WB-HIIT (6 females, 23 ± 1 years) and fourteen were included in a non-exercise control group (CTL; 6 females, 24 ± 4 years). All took part to pre- and post-intervention assessments of body composition, peak oxygen uptake (VO2peak) and first ventilatory threshold (VT1; index of aerobic capacity), dynamic (leg press 3-repetition maximum) and isometric strength (knee extensors maximal isometric contractions with assessment of voluntary activation), and muscle endurance during an isometric submaximal contraction maintained till exhaustion. WB-HIIT consisted in 30-s all-out whole-body exercises interspaced with 30 s of active recovery. Training sessions were performed at home by means of videos with demonstration of exercises. Heart rate was monitored during sessions. Results: WB-HIIT increased VO2peak (5%), VT1 (20%), leg lean mass (3%), dynamic (13%) and isometric strength (6%), and muscle endurance (28%; p < 0.05), while they did not improve in CTL. VO2peak increase was correlated (r = 0.56; p < 0.05) with the time spent above 80% of maximal heart rate during training sessions. Isometric strength increase was correlated with change in voluntary activation (r = 0.74; p < 0.01). Conclusion: The home-based WB-HIIT induced concomitant cardiorespiratory fitness and neuromuscular improvements. The predominant effect was observed for aerobic capacity and muscle endurance which could improve exercise tolerance and reduce fatigability.

Exercise as a non-pharmacological intervention to protect pancreatic beta cells in individuals with type 1 and type 2 diabetes.

AIMS/HYPOTHESIS: Diabetes is characterised by progressive loss of functional pancreatic beta cells. None of the therapeutic agents used to treat diabetes arrest this process; preventing beta cell loss remains a major unmet need. We have previously shown that serum from eight young healthy male participants who exercised for 8 weeks protected human islets and insulin-producing EndoC-ßH1 cells from apoptosis induced by proinflammatory cytokines or the endoplasmic reticulum (ER) stressor thapsigargin. Whether this protective effect is influenced by sex, age, training modality, ancestry or diabetes is unknown. METHODS: We enrolled 82 individuals, male or female, non-diabetic or diabetic, from different origins, in different supervised training protocols for 8-12 weeks (including training at home during the COVID-19 pandemic). EndoC-ßH1 cells were treated with 'exercised' serum or with the exerkine clusterin to ascertain cytoprotection from ER stress. RESULTS: The exercise interventions were effective and improved [Formula: see text] values in both younger and older, non-obese and obese, non-diabetic and diabetic participants. Serum obtained after training conferred significant beta cell protection (28% to 35% protection after 4 and 8 weeks of training, respectively) from severe ER stress-induced apoptosis. Cytoprotection was not affected by the type of exercise training or participant age, sex, BMI or ancestry, and persisted for up to 2 months after the end of the training programme. Serum from exercised participants with type 1 or type 2 diabetes was similarly protective. Clusterin reproduced the beneficial effects of exercised sera. CONCLUSIONS/INTERPRETATION: These data uncover the unexpected potential to preserve beta cell health by exercise training, opening a new avenue to prevent or slow diabetes progression through humoral muscle-beta cell crosstalk.

Right ventricular-pulmonary arterial coupling impairment and exercise capacity in obese adults.

Background: Obesity-related exercise intolerance may be associated with pulmonary vascular and right ventricular dysfunction. This study tested the hypothesis that decreased pulmonary vascular reserve and right ventricular (RV)-pulmonary arterial (PA) uncoupling contributes to exercise limitation in subjects with obesity. Methods: Seventeen subjects with obesity were matched to normo-weighted healthy controls. All subjects underwent; exercise echocardiography, lung diffusing capacity (DL) for nitric oxide (NO) and carbon monoxide (CO) and an incremental cardiopulmonary exercise test. Cardiac output (Q), PA pressure (PAP) and tricuspid annular plane systolic excursion (TAPSE) were recorded at increasing exercise intensities. Pulmonary vascular reserve was assessed by multipoint mean PAP (mPAP)/Q relationships with more reserve defined by lesser increase in mPAP at increased Q, and RV-PA coupling was assessed by the TAPSE/systolic PAP (sPAP) ratio. Results: At rest, subjects with obesity displayed lower TAPSE/sPAP ratios (1.00 ± 0.26 vs. 1.19 ± 0.22 ml/mmHg, P < 0.05), DLCO and pulmonary capillary blood volume (52 ± 11 vs. 64 ± 13 ml, P < 0.01) compared to controls. Exercise was associated with steeper mPAP-Q slopes, decreased TAPSE/sPAP and lower peak O2 uptake (VO2peak). The changes in TAPSE/sPAP at exercise were correlated to the body fat mass (R = 0.39, P = 0.01) and VO2peak (R = 0.44, P < 0.01). Conclusion: Obesity is associated with a decreased pulmonary vascular and RV-PA coupling reserve which may impair exercise capacity.

Effectiveness of Whole-Body High-Intensity Interval Training on Health-Related Fitness: A Systematic Review and Meta-Analysis.

Due to its versatility, whole-body high-intensity interval training (WB-HIIT) can be proposed to the general population and patients to improve health-related fitness. However, its effectiveness compared to traditional aerobic continuous or interval trainings has yet to be determined. A search of four electronic databases was conducted. Studies reporting the effects of WB-HIIT on cardiorespiratory fitness (CRF), fat mass, fat-free mass, musculoskeletal fitness and metabolic risk factors were included. Standardized mean differences (SMD) between WB-HIIT and no exercise or traditional aerobic trainings were calculated. A meta-regression assessed the effect of total training time on the different outcomes. Twenty-two studies were included in the systematic review and nineteen in the meta-analysis. Compared to no exercise, WB-HIIT improves CRF (SMD: 0.75; 95%CI: 0.28, 1.23; p < 0.001), fat-free mass (SMD: 0.38; 95%CI: 0.11, 0.65; p < 0.001), fat mass (SMD: 0.40; 95%CI: 0.09, 0.72; p < 0.001) and musculoskeletal fitness (SMD: 0.84; 95%CI: 0.61, 1.08; p < 0.001). Compared to other aerobic trainings, WB-HIIT has a lower effect on CRF (SMD: −0.40; 95%CI: −0.70, −0.11; p = 0.007), a similar effect on fat-free mass (SMD: −0.04; 95%CI: −0.44, 0.35; p = 0.8) and fat mass (SMD: −0.07; 95%CI: −0.39, 0.25; p = 0.7), and a larger effect on musculoskeletal fitness (SMD: 0.42; 95%CI: 0.14, 0.71; p = 0.003). WB-HIIT overall effect and specific effect on CRF and fat mass were associated with total training time. The systematic review did not provide evidence of metabolic risk improvement. Despite a slightly lower effect on CRF, WB-HIIT is equally effective as traditional aerobic trainings to improve body composition and more effective to enhance musculoskeletal fitness, which is essential for execution of daily tasks.

Lean Mass Loss and Altered Muscular Aerobic Capacity after Bariatric Surgery.

INTRODUCTION: Patients undergoing weight loss surgery do not improve their aerobic capacity or peak oxygen uptake (VO2peak) after bariatric surgery and some still complain about asthenia and/or breathlessness. We investigated the hypothesis that a post-surgery muscular limitation could impact the ventilatory response to exercise by evaluating the post-surgery changes in muscle mass, strength, and muscular aerobic capacity, measured by the first ventilatory threshold (VT). METHODS: Thirteen patients with obesity were referred to our university exercise laboratory before and 6 months after bariatric surgery and were matched by sex, age, and height to healthy subjects with normal weight. All subjects underwent a clinical examination, blood sampling, and body composition assessment by dual-energy X-ray absorptiometry, respiratory and limb muscle strength assessments, and cardiopulmonary exercise testing on a cyclo-ergometer. RESULTS: Bariatric surgery resulted in a loss of 34% fat mass, 43% visceral adipose tissue, and 12% lean mass (LM) (p < 0.001). Absolute handgrip, quadriceps, or respiratory muscle strength remained unaffected, while quadriceps/handgrip strength relative to LM increased (p < 0.05). Absolute VO2peak or VO2peak/LM did not improve and the first VT was decreased after surgery (1.4 ± 0.3 vs. 1.1 ± 0.4 L min-1, p < 0.05) and correlated to the exercising LM (LM legs) (R = 0.84, p < 0.001). CONCLUSIONS: Although bariatric surgery has numerous beneficial effects, absolute VO2peak does not improve and the weight loss-induced LM reduction is associated to an altered muscular aerobic capacity, as reflected by an early VT triggering early exercise hyperventilation.