Combined effect of daily physical activity and social relationships on sleep disorder among older adults: cross-sectional and longitudinal study based on data from the Kasama study.

BACKGROUND: This study investigated whether daily physical activity of older adults, combined with social relationships, is associated with the risk of sleep disorder. Further, it determined whether a high level of one variable with a low level of the other, leads to a significantly lower risk of sleep disorder than low levels of both. METHODS: The sample comprised 1339 community-dwelling older Japanese adults: 988 in Study 1 and 351 in Study 2. The level of daily physical activity and range of social relationships were assessed using the Physical Activity Scale for the Elderly and the Lubben Social Network Scale, respectively. The Pittsburgh Sleep Quality Index was used to assess sleep disorder. To test the combined relationships and effects in Studies 1 and 2, the medians for the respective scores of each of the following four groups that the participants were categorized into, were calculated: (1) low activity group with low social relationships, (2) low activity group with high social relationships, (3) high activity group with low social relationships, and (4) high activity group with high social relationships. After adjusting for potential confounders, a logistic regression analysis was conducted in Study 1. After adjusting for potential confounders, a Cox proportional hazards regression analysis was conducted in Study 2. RESULTS: Study 1 revealed that the high activity group with high social relationships showed a significantly lower risk of sleep disorder (ORs: 0.585, 95% CI: 0.404-0.847) than the low activity group with low social relationships. Study 2 also revealed that the high activity group with high social relationships showed a significantly lower prevalence of sleep disorder (HRs: 0.564, 95% CI: 0.327-0.974) than the low activity group with low social relationships. CONCLUSIONS: Our findings suggest that for older adults with high social relationships, being physically active is favorably associated with sleep quality. However, a high level of one variable with a low level of the other has not been confirmed in improving sleep quality among older adults.

Associations between exercising in a group and physical and cognitive functions in community-dwelling older adults: a cross-sectional study using data from the Kasama Study.

[Purpose] To examine the associations of exercise habits, particularly exercising in a group, with physical and cognitive functions in community-dwelling older adults. [Participants and Methods] A total of 615 older adults participated in this cross-sectional study. We conducted three physical performance tests (grip strength, five times sit-to-stand, and 5-meter walk tests) and the Five-Cog test (attention, memory, visuospatial, language, and reasoning). We investigated exercise habits using questionnaires and classified the participants into three groups as follows: those who did not exercise (n=86), those who exercised alone (n=168), and those who exercised in a group (n=362). To clarify the associations of exercise habits with physical and cognitive functions, we used the analysis of covariance with adjustment for potential confounders. [Results] The participants who exercised in a group had better lower limb strength than those who exercised alone and better scores for all the variables than the non-exercisers. Furthermore, those who exercised in a group scored significantly higher on the attention, memory, visuospatial, and overall cognitive function tests than those who exercised alone. [Conclusion] Our results highlight the importance of the social aspects associated with exercising, such as the presence of exercise peers, to improve the physical and cognitive health of older adults.

Effects of sedentary behavior and physical activity on sleep quality in older people: A cross-sectional study.

The aim of this cross-sectional study was to investigate the influence of replacing sedentary time with time engaged in one of two levels of physical activity on sleep quality using an isotemporal substitution model. The participants were 70 community-dwelling older Japanese adults (approximately 70% female). Physical activity types were measured using a triaxial accelerometer and categorized based on intensity as sedentary, light-intensity, and vigorous-intensity. The Pittsburgh Sleep Quality Index assessed subjective sleep quality. Objective sleep parameters were assessed using an actigraph. A series of multi-linear regression models analyzed the statistical relationships. Our findings showed that replacing 30 min of sedentary activity per day with an equal period of light-intensity physical activity significantly influenced sleep quality parameters. However, there was no significant difference in sleep quality when light-intensity activity was replaced with vigorous-intensity activity. Engaging in one activity type means less available time for other types of activity; habitual replacement of sedentary activity with light-intensity physical activity might have long-term benefits on the sleep quality of older people.