Abstract
BACKGROUND: Adiposity and low physical fitness are critical public health issues, particularly when taking into consideration the worldwide shift from active to sedentary lifestyles. Thus, the aim of this study was to determine how reallocations of time between sleep, sedentary behaviour (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) are associated with adiposity and physical fitness among Thai urban employees. METHODS: Cross-sectional data were collected from a random sample of 424 adults working in Bangkok. Daily durations of SB, LPA, and MVPA were estimated using accelerometers, while sleep duration was obtained from sleep logs. We used body mass index (BMI), percent body fat, and waist circumference as adiposity indicators and maximum oxygen consumption (VO(2 max)), dynamometer-measured handgrip, back and leg strength, and flexibility assessed using sit-and-reach test as fitness indicators. RESULTS: Reallocating 15 min/day to SB from the remaining behaviours was associated with on average 0.19 mL/kg/min (95% confidence interval [CI]: -0.35, -0.03) lower VO(2 max). Reallocating 15 min/day to LPA from the remaining behaviours was associated with on average 0.15 kg/m(2) (95% CI: 0.03, 0.27) higher BMI and 0.34 cm (95% CI: 0.01, 0.67) greater waist circumference. Reallocating 15 min/day to MVPA from the remaining behaviours was associated with on average 1.52 cm (95% CI: -2.85, -0.19) smaller waist circumference and 1.77 cm (95% CI: 0.69, 2.85) greater flexibility. CONCLUSIONS: There is a beneficial association of reallocating more time to MVPA with adiposity and fitness, and a detrimental association of reallocating more time to SB and LPA with adiposity.