Sleep and functional capacity in adults: Cross-sectional associations among self-report and objective assessments

Longitudinal association of sleep quality with physical performance measures: SABE cohort study, Brazil

OBJECTIVES

The aim of this study was to investigate the longitudinal association of sleep with physical performance in a representative sample of non-institutionalised older adults residing in the municipality of São Paulo, Brazil.

STUDY DESIGN

Prospective cohort study.

METHODS

The current longitudinal study used data extracted from the Health, Well-being, and Aging Study (Estudo Saúde Bem-Estar e Envelhecimento [SABE]). The study population consisted of individuals aged ≥60 years who participated in the study in 2010 or 2015. Dependent variables included the Short Physical Performance Battery (SPPB) and gait speed. Independent variables of interest were self-reported sleep difficulty, daytime sleepiness and sleep quality. The longitudinal association between sleep variables and the outcomes was evaluated using Generalised Estimating Equations (GEE) Models adjusted for covariates. All the variables, except age, sex and schooling, were assessed at baseline and follow-up visits (2010 and 2015).

RESULTS

The analyses included 2205 observations from 1559 individuals. The population mean age was 72 years in 2010 and 71 years in 2015, with a higher prevalence of women in both years. Between 2010 and 2015, there was a decline in the SPPB score and gait speed. Daytime sleepiness was negatively associated with the SPPB score [Coef.: -0.38 (95% confidence interval {CI}: -0.56, -0.21)] and gait speed [Coef.: -0.03 (95% CI: -0.05, -0.01)]. Poor sleep quality was negatively associated with the SPPB score [Coef.: -0.29 (95% CI: -0.57, -0.01)] and gait speed [Coef.: -0.03 (95% CI: -0.06, -0.00)].

CONCLUSIONS

Daytime sleepiness and poor sleep quality are associated with compromised physical performance in non-institutionalised older adults, and this association remained consistent over time.

The effect of explicit and implicit online self-compassion interventions on sleep quality among Chinese adults: A longitudinal and diary study

Objective

This study aimed to investigate the effects of explicit and implicit online intervention methods for self-compassion on improving sleep quality among Chinese adults.

Methods

A total of 328 adult participants were recruited to complete the Pittsburgh Sleep Quality Questionnaire and Self-compassion Scale, and 168 participants were randomly assigned to one of three different conditions: two self-compassion intervention groups (self-compassion writing intervention asked participants to write several sentences with self-compassion, and self-compassion combination intervention asked participants to combine words into complete sentences with self-compassion) and one control group. After 1 week of online self-compassion intervention with daily sleep quality measured simultaneously, 150 participants completed the posttest of the Pittsburgh Sleep Quality Questionnaire and Self-Compassion Scale.

Results

The pretest and posttests results showed that the self-compassion level and sleep quality of the self-compassion writing intervention group were significantly better than those of the control group. However, there was no significant difference between the self-compassion combination intervention group and the control group. For the diary tracking results, sleep quality was significantly better for both the self-compassion writing intervention group and self-compassion combination intervention group than the control group, however, the self-compassion writing intervention group showed great improvements.

Conclusion

Both self-compassion writing and combination interventions were effective in improving sleep quality, and the effect of self-compassion writing was more stable.

The Association Between Gait Speed and Sleep Problems Among Chinese Adults Aged 50 and Greater

Objective

The relationship between sleep problems and walking speed has been less explored. The present cross-sectional study was to investigate the association between sleep quality and sleep duration and gait speed in Chinese adults.

Methods

A total of 13,367 participants were recruited in this cross-sectional study, retrieving the data from the Global Aging and Adult Health Survey (SAGE). Gait speed was measured using the 4-m walking test. Age, sex, education years, smoking status, alcohol consumption, physical activity, chronic disease, sleep problems were self-reported by participants. To explore the association between sleep problems and gait speed, multivariate linear regression models were employed.

Results

In the adjusted model, poor sleep quality and longer sleep duration were significantly associated with slower normal walking speed in Chinese adults (p < 0.001). Moreover, there were negatively significant associations between normal gait speed and sleep quality in male adults (p < 0.01).

Conclusion

The findings suggest that slower normal walking speed was associated with poor sleep quality and longer sleep duration (>8 h) in Chinese male adults.

Between-person and within-person associations of sleep and working-memory in the everyday lives of old and very old adults: initial level, learning, and variability

STUDY OBJECTIVES

Sleep duration affects various aspects of cognitive performance, such as working-memory and learning, among children and adults. However, it remains open, whether similar or even stronger associations exist in old and very old age when changes in sleep and cognitive decrements are common.

METHODS

Using repeated daily-life assessments from a sample of 121 young-old (66-69 years old) and 39 old-old adults (84-90 years old), we assessed links between sleep duration and different aspects of working-memory (initial level, practice-related learning, and residualized variability) between and within persons. Participants reported their sleep durations every morning and performed a numerical working-memory updating task six times a day for seven consecutive days.

RESULTS

Both people who slept longer and those who slept shorter than the sample average showed lower initial performance levels, but a stronger increase of WM over time (i.e. larger learning effects), relative to people with average sleep. Sleep duration did not predict performance variability. Within-person associations were found for people sleeping relatively little on average: For them, working-memory performance was lower on days with shorter than average sleep, yet higher on days with longer than average sleep. Except for lower initial levels of working-memory in old-old adults, no differences between young-old and old-old adults were observed.

CONCLUSION

We conclude that sufficient sleep remains important for working-memory performance in older adults and that it is relevant to include different aspects of working-memory performance, because effects differed for initial performance and learning.