Joint effect of light and moderate-to-vigorous physical activity on longevity

The objective of this study was to assess the combined effect of light and moderate-to-vigorous physical activity on all-cause mortality risk. This was a prospective cohort study of 3949 adults aged 40 and older. Exposures were the volume (average min/day) and dose (average MET min/day) of light activity and moderate-to-vigorous activity measured by accelerometers. The outcome was all-cause mortality. Median values were 324 min/day for light activity and 11 min/day for moderate-to-vigorous activity. Approximately 65% of moderate-to-vigorous activity was intermittent, and 99% was performed at a moderate intensity. Hazard ratios for all-cause mortality were 0.38 (95% CI: 0.29, 0.51) for 335 min/day of light activity alone and 0.43 (95% CI: 0.34, 0.56) for 20 min/day of moderate-to-vigorous activity alone. Combining 335 min/day of light activity with 20 min/day of moderate-to-vigorous activity was associated with a substantially lower hazard ratio of 0.17 (95% CI: 0.12, 0.33). A more modest combination-220 min/day of light activity and 10 min/day of moderate-to-vigorous activity-was also associated with a large reduction in mortality risk (hazard ratio: 0.33; 95% CI: 0.27, 0.41). These findings underscore the importance of promoting all intensities of physical activity as part of daily routines.