Frequent vs single active bouts differentially affect movement behavior and energy balance in adults with overweight/obesity

ObjectiveTo investigate the effects of breaking up prolonged sedentary behavior (SB) on daily movement behavior and energy balance in adults with overweight/obesity. MethodsThirty participants (16F/14M; 34.2{+/-}7.3y; 29.5{+/-}3.2kg/m2) were randomized to either BREAK (nine hourly 5-min brisk walking bouts) or a duration-matched intervention, ONE (45-min brisk walking), both performed 5 days/week for 6 weeks. Pre- and post-intervention, daily SB and physical activity (PA; accelerometry), body composition (doubly labeled water [DLW]), total daily energy expenditure (TDEE; DLW), appetite, and fasting leptin were measured. Linear-mixed effects models tested time effects and time-by-group interactions. ResultsOnly BREAK reduced prolonged SB (-8%; interaction: p=0.043). Both groups shifted SB-PA composition toward greater moderate-to-vigorous PA with proportional reductions in SB and light PA (time: all p[≤]0.011), which were associated with increases in TDEE (+0.67 MJ/d; time: p=0.040). Body and fat mass increased in ONE only (interaction: p=0.061 and p=0.055). No differences were noted in energy intake, appetite, or leptin levels. ConclusionsSpreading short PA bouts throughout the day increases MVPA and TDEE to the same extent as a traditional continuous PA bout. Future studies should investigate whether minor differences in body composition are driven by distinct behavioral/physiological compensations influenced by the daily pattern of PA/SB. STUDY IMPORTANCE QUESTIONSO_LIWhat is already known about this subject? O_LIAcutely, breaking up prolonged sedentary behavior (SB) with short bouts of physical activity (PA) increases energy expenditure and reduces food cravings compared to a single continuous PA bout. C_LIO_LISingle continuous PA bouts have been associated with compensatory reductions in non-exercise activities (daily living activities) in some studies, which may attenuate increases in total daily energy expenditure (TDEE) and limit effects on body mass and adiposity. C_LI C_LIO_LIWhat are the new findings in your manuscript? O_LIPerforming brisk walking either through frequent, short bouts spread across the day or as a single continuous bout over 6 weeks increases moderate-to-vigorous PA (MVPA) at the expense of SB and light PA and increases TDEE to a similar extent in adults with overweight or obesity. C_LIO_LIHowever, only the frequent, short active breaks reduced time spent in prolonged SB (>60 min), an independent cardiometabolic health risk factor. C_LIO_LIDespite no differences in energy intake, appetite, or plasma leptin concentration, the single continuous bouts were associated with a small, non-robust increase in body and fat mass, whereas these remained stable in the active breaks group, suggesting differential compensatory adaptations. C_LI C_LIO_LIHow might your results change the direction of research or the focus of clinical practice? O_LIPromoting frequent, short bouts of PA throughout the day can improve daily movement and help meet current PA/SB guidelines to a similar extent as traditional PA strategies, while also reducing prolonged sedentary time. C_LIO_LIThis strategy may help limit compensatory responses sometimes observed in response to continuous MVPA bouts, offering a new tool to manage body weight. C_LIO_LIHowever, differences in body composition outcomes were small and not robust, and future studies are needed to determine whether these patterns translate into meaningful long-term effects on energy balance and weight regulation. C_LI C_LI