Curvilinear dose-response association of physical activity with clinically diagnosed stress: Prospective cohort with 74,000 individuals.

This study examined the prospective dose-response association of accelerometer-derived physical activity with clinically diagnosed stress. We included adults aged 40-69 years from the UK Biobank cohort, free of severe disease at baseline, who participated in accelerometer measurements. Moderate- to vigorous physical activity (MVPA) at baseline was derived through one-week wrist-worn accelerometry. Clinically diagnosed severe stress at follow-up was defined by hospitalization with ICD-10 codes Z73.3 (stress, not elsewhere classified) and Z56.6 (work-related stress). Restricted cubic splines determined the prospective dose-response association between MVPA and stress, adjusting for relevant confounders. The study followed 74,715 individuals (mean age 55.2 years [SD 7.8]; 58% women); for a median of 7.9 years, during which 533 individuals (0.7%) developed stress. Higher levels of MVPA were curvilinearly associated with reduced stress risk, with the steepest minute-per-minute risk reduction from 15 (HR 0.98 [95%CI, 0.96-0.99]) to 220 (HR 0.74 [95%CI, 0.59-0.92]) minutes per week. The greatest risk reduction was observed at 1230 min per week (HR 0.59 [95%CI, 0.35-0.99]). A curvilinear dose-response association exists between MVPA and reduced risk of clinically diagnosed stress, with the greatest minute-per-minute incremental benefits observed from 15 to 220 min per week.