Acute effects of "exercise snacks" on postprandial glucose and insulin responses in populations at metabolic risk: a meta-analysis with exploratory meta-regression and vascular outcomes.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized crossover trials
PubMed 42558375 · doi:10.3389/fendo.2026.1912963
What was done
Six databases were searched for acute randomized crossover trials evaluating exercise snacks (short, frequent physical activity bouts interrupting prolonged sitting) versus uninterrupted sitting in sedentary adults with metabolic risk. Standard errors were hierarchically back-calculated from paired test statistics, insulin data were isolated from C-peptide, and risk of bias was assessed with the Cochrane RoB 2 tool for crossover trials. Random-effects meta-analyses and exploratory meta-regressions were conducted for postprandial glucose incremental area under the curve (iAUC), insulin iAUC, and exploratory vascular outcomes.
What was found
Eight trials comprising 159 participants were included. In five trials reporting glucose iAUC, exercise snacks significantly reduced postprandial glucose (MD = -5.69 mmol·h/L, 95% CI -9.38 to -2.00, P = 0.003), with high heterogeneity (I² = 85%) and a 95% prediction interval crossing the null (-13.53 to 2.15 mmol·h/L). Postprandial insulin iAUC showed a non-significant reduction (MD = -902.64 pmol·h/L, 95% CI -1889.11 to 83.82, P = 0.073, k = 4; I² = 98%). Exploratory meta-regression showed no statistically significant moderation by baseline metabolic status (P = 0.176) or exercise intensity (P = 0.057). Vascular outcomes were limited to two flow-mediated dilation trials and one endothelin-1 trial.
Why it matters
This review shows that brief activity snacks acutely blunt postprandial glucose excursions in individuals at metabolic risk under laboratory conditions. However, high heterogeneity and imprecise prediction intervals mean these findings cannot yet support a specific clinical prescription.
Limits
The total evidence base was small, with only 159 participants across 8 studies and 4 to 5 studies per primary outcome. Substantial statistical heterogeneity was present for both glucose and insulin, and the prediction interval for glucose included the possibility of no effect. Studies assessed only acute responses in controlled laboratory settings without long-term follow-up or free-living adherence data, and vascular endpoints were too sparse for firm conclusions.
Cited by
- supports Performing short bouts of exercise snacks immediately before or after meals improves blood glucose control and promotes rapid glucose uptake via GLUT4 transporters.