Device-quantified vigorous intermittent lifestyle physical activity and risk of incident depression and anxiety among non-exercising adults

Background: Physical activity is a well-established modifiable risk factor for depression and anxiety. However, whether vigorous intermittent lifestyle physical activity (VILPA), defined as short, sporadic bouts embedded in daily life, confers mental health benefits remains unclear. We aimed to examine the associations of accelerometer-measured VILPA with risks of incident depression and anxiety among non-exercising adults. Methods: This prospective cohort study included 19,962 non-exercising adults (mean age 62.3 years) from the UK Biobank, free of depression and anxiety at baseline (2013-2015), with 7-day wrist-worn accelerometry data. Cox proportional hazards models and restricted cubic splines were used to examine associations between average daily duration of VILPA bouts lasting up to 1 or 2 minutes and these outcomes. Findings: Over an average follow-up of 7.8 years, 469 participants developed depression and 536 developed anxiety. Approximately 94.6% of participants engaged in VILPA bouts lasting up to 1 minute. Daily VILPA duration exhibited L-shaped associations with both depression and anxiety. Compared with participants who accumulated no VILPA, the whole-sample median daily VILPA duration for bouts lasting up to 1 minute, 4.1 minutes, was associated with a hazard ratio of 0.70 (95% confidence interval [CI]: 0.56-0.88) for depression and 0.79 (95% CI: 0.64-0.97) for anxiety. Findings were similar for VILPA bouts lasting up to 2 minutes. Interpretation: Among non-exercisers, even small amounts of VILPA were associated with substantially lower risks of depression and anxiety, highlighting the potential of high-intensity incidental physical activity as a feasible strategy for preventing depression and anxiety, particularly among individuals unable or unwilling to engage in structured exercise.