Effect of telling older adults their predictive physical fitness age on physical activity: A quasi-experimental study

Physical activity plays an essential role in preventing diseases and improving overall health. Promoting physical activity has become an important intervention against low physical fitness and chronic diseases in older adults. This study aimed to determine whether telling older people their predictive physical fitness age prompts physical activity. Two hundred and fifty-three older Chinese people were assigned single-blindly to either an intervention group (n = 140) or control group (n = 113) in this quasi-experimental study. Participants in the intervention group were informed of the predictive physical fitness age and taught the difference from their chronological age while participants in the control group were not. Participants in both groups were encouraged to get more physical activities each day. The primary outcome was physical activity, and the secondary outcome was the change in physical fitness age. Results showed that for older adults with low physical fitness, all physical activity parameters (vigorous physical activity, moderate physical activity, walking, total physical activity and sitting) showed a significant difference between intervention and control groups after 2 and 12 weeks (p < 0.05). Moreover, physical fitness age was improved remarkably after 12 weeks compared to the control group (73.57 ± 5.75 vs. 66.85 ± 6.33 years, p < 0.05). For older adults with normal physical fitness, a remarkable difference was observed in moderate physical activity, total physical activity, and sitting between intervention and control groups after 2 weeks (p < 0.05), but the difference disappeared after 12 weeks. For older adults with high physical fitness, no significant changes were found between groups (p > 0.05). The findings suggest that telling older people their predictive physical fitness age can become a viable motivational tool to promote physical activity especially for those with low physical fitness, thereby improving their physical fitness age and overall health.