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.

These results suggest that AT before RT combined with fortified milk consumption has similar effects on skeletal muscle mass and strength compared with RT alone, but it may be a more useful strategy to improve physical performance in older adults. Although the mechanism of our intervention is uncertain, our program would be an effective prevention for sarcopenia in older adults.

The majority of patients with insomnia are treated with hypnotic agents. In the present study, we evaluated the side-effect profile of an orexin receptor antagonist and γ-aminobutyric acid A (GABAA) receptor agonist on physical/cognitive functions upon forced awakening. This double-blind, randomized, placebo-controlled, cross-over study was conducted on 30 healthy male subjects. Fifteen minutes before bedtime, the subjects took a pill of suvorexant (20 mg), brotizolam (0.25 mg), or placebo and were forced awake 90 min thereafter. Physical- and cognitive-function tests were performed before taking the pill, after forced awakening, and the next morning. Polysomnographic recordings revealed that the efficacies of the hypnotic agents in prolonging total sleep time (∼30 min) and increasing sleep efficiency (∼6%) were comparable. When the subjects were allowed to go back to sleep after the forced awakening, the sleep latency was shorter under the influence of hypnotic agents (∼2 min) compared to the placebo trial (24 min), and the rapid eye movement latency was significantly shorter under suvorexant (98.8, 81.7, and 48.8 min for placebo, brotizolam, and suvorexant, respectively). Although brotizolam significantly impaired the overall physical/cognitive performance (sum of z score) compared with placebo upon forced awakening, there was no significant difference in the total z score of performance between suvorexant and placebo. Notably, the score for static balance with the eyes open was higher under suvorexant compared to brotizolam administration. The energy expenditure was lower under suvorexant and brotizolam compared with the placebo. The effect size of brotizolam (d = 0.24) to reduce the energy expenditure was larger than that of suvorexant (d < 0.01).

We clarified the relationship between occupational dysfunction and social isolation among community-dwelling adults. We used a self-administered questionnaire with a cross-sectional study for 2879 independently living older adults in Kasama City, Japan. Participants responded to a self-reported questionnaire in November 2019. Occupational dysfunction and social isolation were assessed. The participants were classified into two groups: healthy occupational function group, and occupational dysfunction group. To examine the relationship between occupational dysfunction and social isolation, we performed a logistic regression analysis with social isolation as a dependent variable and occupational dysfunction as an independent variable. In the crude model, the occupational dysfunction group had a higher risk of social isolation than the healthy occupational function group (odds ratio (OR) = 2.04; 95% confidence interval (CI), 1.63–2.55; p < 0.001). In the adjusted model, the occupational dysfunction group had a higher risk of social isolation than the healthy occupational function group (OR = 1.51; 95% CI, 1.17–1.94; p = 0.001). The results showed that occupational dysfunction was significantly associated with social isolation. These results can be used in constructing a support method for social isolation from a new perspective.

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