Accelerometer-derived "weekend warrior" and regular physical activity on long-term risk of irritable bowel syndrome and subsequent depression: a large-scale prospective cohort study.

BACKGROUND

The WHO recommends ≥150 min/week of moderate-to-vigorous physical activity (MVPA) for optimal health. Whether weekend warrior (WW) or regular physical activity (PA) patterns differently influence risks of irritable bowel syndrome (IBS) and subsequent depression is unclear. This study explored these associations using accelerometer-derived PA.

METHODS

We included 84,799 UK Biobank participants with one-week accelerometer data to assess incident IBS using Cox models. Restricted cubic splines evaluated dose-response relationships and identified optimal and minimal candidate MVPA doses. Participants were classified as inactive, WW, or regularly active using guideline (150 min/week) and statistical thresholds. Among 3,976 baseline IBS patients, guideline-based groups were used to examine MVPA and subsequent depression risk with Cox models.

RESULTS

Over a median follow-up of 8.0 years, 962 participants developed IBS. MVPA showed a nonlinear inverse association, plateauing at 225 min/week, with a minimal candidate dose of 80 min/week. Both WW and regular activity were linked to lower IBS risk using 150 min/week (WW: HR 0.75, 95% CI 0.65-0.87; regular: HR 0.73, 95% CI 0.61-0.88) and 80 min/week thresholds (WW: HR 0.75, 95% CI 0.64-0.88; regular: HR 0.68, 95% CI 0.56-0.83). Among IBS patients, both WW (HR 0.61, 95% CI 0.42-0.89) and regular activity (HR 0.65, 95% CI 0.41-1.03) demonstrated comparable inverse associations with subsequent depression, with no significant difference between the two patterns.

CONCLUSION

Both WW and regular MVPA were similarly associated with a lower IBS risk, with minimal and optimal candidate doses of 80 and 225 min/week, respectively. Among IBS patients, both activity patterns demonstrated comparable inverse associations with subsequent depression, although findings were constrained by limited statistical power.