Volitional lifestyle in healthy elderly: its relevance to rest-activity cycle, nocturnal sleep, and daytime napping.

Sleep-related problems are prevalent among the aged. The present study examined the influence of a mentally active or "volitional" lifestyle on the rest-activity cycle, nocturnal sleep, and daytime napping in the healthy elderly. 14 aged individuals with a high Volitional lifestyle (M = 74.1 yr. old) and 14 with a Low Volitional lifestyle (M = 73.0 yr. old) were screened by questionnaires including the Philadelphia Geriatric Center Morale scale and the Self-confidence scale. Their activity levels were monitored by a wrist actigraph system for 14 consecutive days. They were also asked to record daily sleep logs. The total times of nocturnal sleep and daytime napping did not differ between the groups. However, the acrophases of circadian (tau = 24 hr.) and circasemidian (tau = 12 hr.) activity cycles were more advanced in the Low Volitional group. In addition, the High Volitional group took a daytime nap with a better timing than did the Low Volitional group: the former started a nap during the phase in which their activity level was going down, whereas the latter when their activity level was going up. These results suggest that high volitional lifestyle may be related to better rest-activity cycle in the healthy elderly.