Vigorous intermittent lifestyle physical activity (VILPA) and mortality risk among US adults: a wearables-based national cohort study

Background Vigorous intermittent lifestyle physical activity (VILPA) completed through normal daily living may offer a time-efficient avenue to accrue physical activity in a behaviorally sustainable manner. However, no research to date has explored its association with mortality in a nationally representative population. Objectives To examine the dose-response association between VILPA and mortality risk in a nationally representative sample of US adults. Methods This study included a nationally representative sample of 3,293 US adults from the 2011-14 National Health and Nutrition Examination Survey (NHANES) who self-reported no participation in structured exercise (52.3% female; mean age: 50.7 [SD: 16.6 years]. The dose-response relationship between VILPA and all-cause mortality was estimated using multivariable-adjusted cubic splines. Average daily frequency (bouts/day) and duration (minutes/day) of VILPA bouts lasting up to one minute were measured using a wrist-worn accelerometer. Results Over the mean (SD) 6.7 (1.4) year follow-up period, 290 all-cause mortality events occurred. Compared to the referent point (0 bouts per day), there was an L-shaped dose-response association where the median frequency (5.3 bouts per day) was associated with a 44% lower risk of all-cause mortality (HR: 0.56; 95% CI: 0.39, 0.82). The dose response curve was less steep beyond approximately 8 bouts per day (HR: 0.46; 95% CI: 0.28, 0.77). Daily duration of VILPA demonstrated a near-linear association with all-cause mortality risk with a median duration of 1.1 minutes associated with an HR of 0.61 (95% CI: 0.42, 0.88). Conclusions Short bursts of intermittent vigorous physical activity were associated with meaningful health benefits in a nationally representative sample of US adults. Future trials are warranted to investigate the effectiveness and feasibility of VILPA-based interventions.