Post-Exercise Balance Vulnerability in Adults with Sedentary Behavior: Sex Differences in Postural and Metabolic Recovery

This study examined the post-exercise window of vulnerability in static postural control after submaximal treadmill exercise in adults with sedentary behavior and evaluated sex differences in balance impairment and recovery. Thirty-four adults with sedentary behavior (17 women, 17 men) performed the Modified Bruce Protocol. Postural sway was assessed at baseline (Pre), immediately post-exercise (Post0), and at 5 (Post5) and 10 (Post10) minutes of recovery using center-of-pressure metrics (sway area, total sway distance, anterior–posterior excursion, medial–lateral excursion). Blood lactate and heart rate were recorded concurrently. Postural sway and blood lactate were analyzed with a two-way mixed ANOVA (time × sex): heart rate and RPE, with stage-wise independent-sample t-tests. Blood lactate increased markedly post-exercise and remained elevated throughout the 10 min recovery window (p < 0.001, η2p = 0.797), with higher levels in men across all time points (main effect of sex, p = 0.006, η2p = 0.215). Heart rate was higher in men at rest and throughout recovery (all p < 0.001; women higher only at Stage 4), returning near resting level in both sexes by Post10. All four postural sway parameters showed significant main effects of time (all p < 0.001, except total sway distance, p = 0.001) without statistically significant sex × time interactions, and all remained significantly elevated above baseline at Post10, indicating that postural recovery was incomplete within the 10 min observation window. Submaximal treadmill exercise induces acute postural control impairment in sedentary adults that persists into early recovery along specific CoP axes. Despite higher lactate in men, postural and metabolic recovery did not dissociate within the 10 min observation window, defining a post-exercise vulnerability window of at least 10 min that may warrant heightened attention to postural stability in this population.