Appropriate Amount of Regular Exercise Is Associated with a Reduced Mortality Risk.

Purpose: This study aimed at investigating whether there is a continuous dose-response relationship between the amount of physical activity (PA) and longevity benefit.

Methods: We evaluated the records of 23,257,723 Koreans age ≥20 yr who had undergone one biennial medical evaluation by the National Health Insurance Corporation. Participants with ≥20 min of vigorous or ≥30 min of moderate PA or walking were stratified into four groups: 0 d·wk; 1-3 d·wk; 4 to 5 d·wk; and 6-7 d·wk. After calculating total metabolic equivalent task-hours per week (MET·h·wk), we created eight categories of MET-hours per week (0, 0.1-4.9, 5.0-9.9, 10.0-14.9, 15.0-19.9, 20.0-24.9, 25.0-29.9, and ≥30.0). Multivariate Cox proportional hazard analyses were performed.

Results: A reverse J-shaped risk curve was observed, with the lowest mortality risk in the participants exercising 4 to 5 d·wk (reference). Participants who did not exercise at all and those who exercised with a PA frequency of 1 to 3 d·wk or 6 to 7 d·wk showed a significantly increased mortality risk compared with the reference group. When we repeated the Cox analysis among the 8 MET·h·wk categories with the participants reporting 20.0 to 24.9 MET·h·wk of PA as the reference group, we found that those with physical inactivity and 25.0-29.9 or ≥30.0 MET·h·wk of PA showed a higher mortality risk than the reference group. These relationships were persistently observed after adjustment for confounders.

Conclusions: An appropriate amount of regular exercise in each specific type of PA was associated with the lowest risk of mortality. The inactive participants showed an increased mortality risk, and daily PA did not show any additional benefit in the mortality risk.