Age differences in the effect of physical activity on depressive symptoms.

This study examined associations between physical activity and depressive symptoms in 1,151 community-dwelling adults in Japan. Physical activity was measured using a pedometer, whereas depressive symptoms were assessed with the Center for Epidemiological Studies-Depression Scale. A structural equation modeling with a cross-lagged panel design revealed that for the older adults (65-79 years of age), daily walking at baseline predicted fewer depressive symptoms at the 2-year follow-up, even after adjusting for confounders. In contrast, the association was not confirmed for the middle-aged adults (40-64 years of age). Findings suggest that age should be considered when estimating the effect of physical activity on psychological well-being.

The impact of health problems on depression and activities in middle-aged and older adults: age and social interactions as moderators.

In this study, we compared the impact of health problems (HPs) on everyday activities and depressive symptoms between middle-aged and older adults. We also examined what type and source of social interactions moderate the noxious effects of HPs. Longitudinal analyses of data with 1,802 Japanese community-dwelling adults indicated that HPs were significantly related to (a) an increase in depressive symptoms among middle-aged adults and (b) a decline in everyday activities among older adults. The former was buffered by emotional family support, whereas the latter (b) was buffered by instrumental family support and, surprisingly, by negative interactions with family. In contrast, social interactions with other friends and acquaintances did not show any moderating effect.

[Effects of shift work schedule on mood changes among female nurses].

This study examined the short-term effects of shift work on mood changes. The subjects were 1,608 Japanese female nurses, working on rotating 3-shift schedules consisted of day, evening, and night shift. Repeated measurements of six dimensions of mood and sleep hours in four consecutive days were analyzed. Prominent changes of subjective fatigue, activity and confusion were observed especially when shift changes occurred (e.g., day shift to night shift or night shift to evening shift). The changes of mood were contingent to those of sleep hours, which suggested the close association between them. However, the mood changes were observed even after adjusting for the effect of sleep hours, indicating that irregular sleep pattern is not the only cause that affects mood.