Abstract
OBJECTIVE: We assessed the association between timing of moderate-to-vigorous physical activity (MVPA) with incident type 2 diabetes (T2D) and glycemic measures. RESEARCH DESIGN AND METHODS: Regression models were used to assess associations between accelerometer-derived MVPA timing and incident T2D in UK Biobank (UKB) (n = 84,528, prospective), prevalent diabetes, and glycemic measures in the National Health and Nutrition Examination Survey (NHANES) (n = 6,998, cross-sectional). RESULTS: In UKB, with early morning (0500-0959) MVPA as reference and before adjustment for total MVPA, "variable-timing" MVPA was associated with the lowest incident T2D risk; while after adjustment, afternoon-evening MVPA (1500-2400) showed the lowest incident T2D risk. In NHANES, afternoon/early evening MVPA was weakly associated with more favorable glycemic measures and lower diabetes prevalence after adjustment for total MVPA. CONCLUSIONS: When keeping total MVPA volume constant, clustering MVPA in the afternoon-evening was associated with the strongest reduction in incident T2D risk, fewer prevalent diabetes, and more favorable glycemic measures.