Effects of Whole-Body High-Intensity Interval Training on Cardiorespiratory Fitness, Musculoskeletal Fitness, Body Composition, and Metabolic Biomarkers in Adults with Overweight and Obesity

Abstract

Highlights What are the main findings? A 10-week whole-body high-intensity interval training (WB-HIIT) improved health-related fitness and body composition, with gains in aerobic capacity, muscular strength and endurance, and a small reduction in central adiposity. What are the implications of the main findings? Obesity is characterized not only by metabolic impairments and reduced aerobic capacity, but also by decreased musculoskeletal fitness. Whole-body HIIT, by combining aerobic and strength components, may offer an effective approach to simultaneously stimulate the cardiovascular and neuromuscular systems. WB-HIIT is a time-efficient and accessible training modality that can be implemented in everyday settings, unlike traditional HIIT performed on cycle ergometers or treadmills. Its minimal equipment, whole-body nature, and adaptability may help overcome common barriers to exercise participation. Abstract Background/Objectives: Identifying accessible and effective exercise interventions is essential for improving health and physical fitness in individuals with overweight or obesity. Whole-body high-intensity interval training (WB-HIIT) is a time-efficient approach that requires minimal equipment and can be adapted to a wide range of settings and fitness levels. Therefore, this study aimed to investigate the effects of WB-HIIT on cardiorespiratory and musculoskeletal fitness, body composition, and metabolic health markers. Methods: Thirty-six healthy adults with overweight were assigned to either a WB-HIIT group (n = 19; 35 ± 9 years; BMI 30.2 ± 3.1 kg/m2) or a control group (n = 17; 33 ± 11 years; BMI 30.3 ± 3.3 kg/m2). Participants completed pre- and post-intervention assessments including dual-energy X-ray absorptiometry (DXA), blood sampling, maximal cardiopulmonary exercise testing, and measures of muscular strength (3 RM) and functional endurance (1 min sit-to-stand and arm curl). The 10-week supervised WB-HIIT (2–3 sessions per week) included a warm-up, 3–4 sets of 10–12 all-out whole-body exercises (30–40 s) interspersed with 20–30 s recovery, and a cool-down. Results: The control group showed no significant changes in any of the assessed parameters after 10 weeks, except for a modest increase in body fat mass. The WB-HIIT group showed significant improvements in cardiorespiratory fitness, evidenced by increases in VO2peak (p < 0.05), maximal treadmill incline (p < 0.01), and first ventilatory threshold parameters (p < 0.05). Maximal strength increased significantly in both the leg and bench press (p < 0.001), accompanied by a significant improvement in upper-limb functional endurance (arm curl, p < 0.05). No significant changes were observed in body weight or BMI, but small reductions were found in body fat percentage, trunk fat mass, and waist circumference (p < 0.05). Except for a modest decrease in glycated hemoglobin (p < 0.05), metabolic blood parameters remained unchanged and were already within the normal range at baseline. Conclusions: A 10-week WB-HIIT intervention improved cardiorespiratory fitness, muscular strength, and upper-limb functional endurance, and elicited a modest reduction in trunk fat mass in individuals with overweight or obesity.