Background: Whether the major components of leisure physical activity (number of types, intensity, frequency, and duration) have independent contribution to mortality reduction and there is a minimum amount of activity beneficial for the elderly remain unclear.
Methods: The prospective follow-up study aimed at examining the relationship between exercise components and total mortality in general elderly population. A total of 2113 persons aged 65 and older participating in 2001 Taiwan National Health Interview Survey were studied. Information regarding leisure physical activity, its energy parameters, other factors at baseline, and vital status at the end of 2003 was analyzed with Cox model.
Results: A total of 197 deaths occurred during a 2-year follow-up. Regular exercisers reduced 35% risk of death compared with sedentary individuals after adjustment for covariates. Moreover, exercisers with a weekly amount of energy exceeding 1000 kcal had significant benefit of risk reduction when energy expenditure is considered. There was a significant dose-response relationship between number of activity and the reduction in total mortality. The benefit on mortality reduction among the three components of total energy amount was only observed in intensity.
Conclusions: For the amount of energy dedicated to leisure physical activity, older persons are recommended to expend at least 1000 kcal per week through regular exercise for mortality reduction. In addition to energy amount, protection of exercise against death also increases with the number of activities. Among the three components of total amount of energy, only intensity is significantly associated with mortality reduction.