How the relationship between physical activity and health changes with age.

In the context of age-related declines in physical activity (PA) and the dramatic increase in ageing populations in many countries, this paper sheds further light on the link between PA and self-perceived health (SPH) by examining whether the magnitude of this relationship is age specific. With a sample of 14,456 Spanish individuals aged 18-69, we estimated three levels of intensity in PA using the International Physical Activity Questionnaire. Individuals who did more PA per week showed higher levels of SPH (β = 0.28; 95% CI 0.24-0.32), and age moderated this relationship, with a positive effect over age 49. People aged 50-59 and 60-69 who practiced PA had higher probabilities of better SPH compared with those aged 40-49 (β = 0.14; 95% CI 0.04-0.24) and (β = 0.32; 95% CI 0.21-0.43), respectively. This association between PA and SPH also depended on the intensity of PA, especially for walking (β = 0.14; 95% CI 0.04-0.24). In particular, in comparison with people age 40-49, a statistically significant relationship with SPH was found among people age 50-59 who walked (β = 0.22; 95% CI 0.07-0.36) and people age 60-69 who did moderate PA (β = 0.38; 95% CI 0.23-0.54). This paper provides a major rationale for the design, organisation and implementation of public policies promoting PA and healthy ageing for different age groups.