Aerobic exercise is recommended for weight management but energy balance is often less negative than predicted from exercise energy expenditure (ExEE).
To examine effects of active commuting and leisure-time exercise on fat loss in women and men with overweight and obesity.
We randomized 130 younger, physically inactive women and men with overweight and obesity (body mass index: 25–35 kg/m2) to 6 months of habitual lifestyle (CON, n=18), active commuting (BIKE, n=35), or leisure-time exercise of moderate (MOD, 50% VO2peak reserve, n=39) or vigorous intensity (VIG, 70% VO2peak reserve, n=38). The primary outcome was change in fat mass measured by dual-energy X-ray absorptiometry which was analyzed intention-to-treat. Accumulated energy balance was calculated based on changes in body composition, and ExEE was calculated based on heart rate monitoring during exercise.
Testing at 3 and 6 months was completed by 95 and 90 participants, respectively. Fat mass was reduced after 3 and 6 months in BIKE (3 months: -3.6 [-5.5; -1.7] kg (mean [95% CI]); 6 months: −4.2 [−6.6; −1.9] kg; both: P<0.001), MOD (3 months: −2.2 [−3.9; −0.4] kg; 6 months: −2.6 [−4.8; −0.5] kg, both: P<0.02), and VIG (3 months: −3.4 [−5.2; −1.7] kg; 6 months: −4.5 [−6.6; −2.3] kg; both: P<0.001) compared with CON. Furthermore, fat loss was greater in VIG compared with MOD (6 months: −1.8 [−3.6; −0.1] kg, P=0.043). Based on the ExEE and the accumulated energy balance MOD compensated for the ExEE (77 [48; 106] %) but not BIKE (38 [−18; 95] %) and VIG (21 [−14; 55] %).
A meaningful fat loss was obtained by 6 months of active commuting and leisure-time exercise, but fat loss was greater with vigorous compared to moderate intensity exercise. Active commuting is an alternative to leisure-time exercise in the management of overweight and obesity. The trial was registered at clinicaltrials.gov as NCT01962259 (main trial) and NCT01973686 (energy metabolism sub-study).