Effects of Accumulated Short Bouts of Exercise on Weight and Obesity Indices in Adults: A Meta-Analysis

Objective: To compile and quantify the effectiveness of accumulated short-bout exercise interventions on reducing the obesity indices in adults using meta-analysis. Data Source: PubMed, PsycINFO, CINAHL, Cochrane Library, and SportDiscus. Study Inclusion and Exclusion Criteria: (1) Description of a short-bout exercise trial (<30 minutes); (2) obesity indices must be measured pre- and postintervention; and (3) only adults and published in English. Data Extraction: Two independent reviewers extracted data and assessed the quality of the studies included. Of 3257 articles retrieved, 18 studies met the inclusion criteria. Based on the Downs and Black checklist, the methodological quality of the included studies was fairly robust. Data Synthesis: Pooled effect sizes (ESs) were calculated using a random effects model. Results: Average intervention length was approximately 16 weeks (ranged from 4 to 72 weeks). All weighted mean ES values for each obesity index measure were non-negative, ranging from small to large (ES = 0.33-0.96) in magnitude. Weighted mean ES for body mass (BM; n = 18; ES = 0.51, 95% confidence interval [CI] = 0.22-0.80), body mass index (BMI; n = 13; ES = 0.61, 95% CI = 0.24-0.97), waist circumference (n = 9; ES = 0.44, 95% CI = 0.15-0.73), body fat percentage (BF%; n = 8; ES = 0.33, 95% CI = 0.09-0.58), skinfold (n = 7; ES = 0.96, 95% CI = 0.39 -1.53), and fat mass (FM; n = 6; ES = 0.55, 95% CI = 0.21-0.90) were statistically significant. Moderator effects of intervention length (weeks) were observed for BM (Q(between) [Cochran's Q: a measure of heterogeneity between studies] = 6.83, P < .05); BMI (Q(between) = 13.93, P < .05); and FM (Q(between) = 10.41, P < .05). Intervention length >10 weeks was more effective than shorter (<= 10) intervention period for reducing BM, BMI, and FM. Conclusion: Accumulated short bouts of exercise have a beneficial effect on reducing the obesity indices among adults. The current study can help health researchers and practitioners in designing their intervention programs, which can be applied within schools, clinics, and communities.