Objective To investigate the effects of breaking up prolonged sedentary behavior (SB) on daily movement behavior and energy balance in adults with overweight/obesity.

Methods Thirty 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.

Results Only 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.

Conclusions Spreading 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 QUESTIONS

What is already known about this subject?

Acutely, 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.

Single 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.

What are the new findings in your manuscript?

Performing 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.

However, only the frequent, short active breaks reduced time spent in prolonged SB (>60 min), an independent cardiometabolic health risk factor.

Despite 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.

How might your results change the direction of research or the focus of clinical practice?

Promoting 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.

This strategy may help limit compensatory responses sometimes observed in response to continuous MVPA bouts, offering a new tool to manage body weight.

However, 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.

The authors have declared no competing interest.

NCT02998892

This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, Grant Number R00DK100465 (to A.B.), and NIH/NCATS Colorado CTSA, Grant Number UL1 TR001082 (to A.B.). This study was also supported by a grant from the Sao Paulo State Research Support Foundation, Grant Number 2023/17782-3 (to H.C.S.A.) and by the American Diabetes Association (Grant 1-25-PDF-103; to A.J.P).

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study was approved by the Colorado Multiple Institutional Review Board (COMIRB; protocol 16-1769) and conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from each participant.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

Clinical Trial Registration: ClinicalTrials.gov: NCT02998892

Funding: This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, Grant Number R00DK100465 (to A.B.), and NIH/NCATS Colorado CTSA, Grant Number UL1 TR001082 (to A.B.). This study was also supported by a grant from the São Paulo State Research Support Foundation, Grant Number 2023/17782-3 (to H.C.S.A.) and by the American Diabetes Association (Grant 1-25-PDF-103; to A.J.P).

The trial protocol, statistical analysis plan, and deidentified datasets generated and analyzed during the current study are available from the corresponding author on reasonable request, via secure file transfer. Data can be shared with researchers for purposes of reproducing the results or conducting meta-analyses and will be available indefinitely from the time of publication.

The trial protocol, statistical analysis plan, and deidentified datasets generated and analyzed during the current study are available from the corresponding author on reasonable request, via secure file transfer. Data can be shared with researchers for purposes of reproducing the results or conducting meta-analyses and will be available indefinitely from the time of publication.