Physical activity dose for generalized anxiety disorder & worry: Results from the Irish longitudinal study on ageing.

The lowest moderate-to-vigorous physical activity (MVPA) dose that conveys protection for Generalized Anxiety Disorder (GAD) and worry is unknown. This study quantified associations of weekly accumulated MVPA doses with GAD and worry across 10 years using data from The Irish Longitudinal Study on Ageing (TILDA). Continuous MVPA (metabolic equivalent of task [MET] minutes per week [MET.min.week-1]; e.g., moderate-intensity brisk walking = 4METs), three-dose and, more precise, five-dose MVPA categories were examined. Worry symptoms and GAD status were measured using the Penn State Worry Questionnaire-Abbreviated and the Composite International Diagnostic Interview. Multivariable negative random effect binomial regression and logistic models adjusted for relevant covariates quantified associations across time. Among the 7,650 participants, compared to no MVPA (0 MET.min.week-1), 18 % (OR: 0.82; 95 %CI: [0.69-0.98]), 22 % (OR: 0.78; [ 0.64-0.95]) and 31 % (OR: 0.69; [0.59-0.79]) lower odds of GAD were found for the doses of 1-<600, 600-<1,200 and ≥2,400 MET.min.week-1 respectively. Post-hoc analysis demonstrated 47 % lower odds (OR: 0.53; (0.36-0.78) of GAD for 1-<200 MET.min.week1 compared to inactivity. Compared to no activity, engaging in even minimal physical activity equivalent of 10 min/day for five days/week of moderate-intensity activity (e.g., brisk walking), may lower the risk of GAD over time among older adults.