Background: The activity patterns of older adults include more light/mild-intensity or "non-exercise" activity and less moderate- to vigorous-intensity activity. The health benefits of this type of activity pattern remain unclear.
Purpose: To examine dose-response associations between physical activity and survival using time-varying analysis to understand the importance of "non-exercise" activity for survival in older adults.
Methods: Participants (N=10,426) were drawn from The English Longitudinal Study of Ageing, a representative sample of men and women aged ≥50 years living in England. Participant data were linked with death records from the National Health Service registries from 2002 to 2011. Analyses were conducted in 2013. Cox proportional hazards models were used to estimate the risk of death according to time-varying estimates of physical activity.
Results: Over an average follow-up of 7.8 years (median follow-up, 8.5 years), there were 1,896 deaths. In models adjusted for comorbidities, psychosocial factors, smoking, and obesity, there was a dose-response association between time-varying physical activity and mortality, with the greatest survival benefit in vigorously active participants. However, participating in mild ("non-exercise")-intensity physical activity was also associated with a lower risk of all-cause mortality (hazard ratio [HR]=0.76, 95% CI=0.69, 0.83); cardiovascular mortality (HR=0.74, 95% CI=0.64, 0.85); and death by other causes (HR=0.67, 95% CI=0.58, 0.78). Time-varying models produced stronger, more robust estimates than models using a single measurement of physical activity at baseline.
Conclusions: Older adults gain health benefits from participating in regular "non-exercise" physical activity, although the greatest benefits are observed for more vigorous activity.
Copyright © 2014 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.