Daytime Napping and Cognitive Health in Older Adults: A Systematic Review

Factors associated with the fragmentation and stability of the rest-activity rhythm in adults and older adults

This cross-sectional study aimed to identify factors related to the fragmentation and stability of the rest-activity rhythm (RAR) in adults and older adults. It is part of a larger research project investigating aspects concerning sleep duration, quality, and disorders in a representative subsample of the population. Sociodemographic data, lifestyle, health habits and subjective sleep variables were obtained; RAR records were collected by means of actigraphy and analyzed using non-parametric variables (IS, IV, M10, L5, RA, sL5, and sM10). Study participants were 313 individuals with complete actigraphy records. There was a prevalence of older adults (50.2%) and females (51.1%). Females, individuals with 4-8 y of education, and those who used alcohol abusively exhibited lower RAR fragmentation. Higher fragmentation was observed in individuals who napped and those reporting poor sleep quality. Greater rhythm stability was evident in females, older adults, those with 4-8 y of education, and those who had a partner. Smokers demonstrated lower RAR stability. These findings may contribute valuable insights for decision-making aimed at preventing and treating issues related to fragmentation and instability of the rhythm and its possible consequences to health.

Self-reported sleep fragmentation and sleep duration and their association with cognitive function in PROTECT, a large digital community-based cohort of people over 50

OBJECTIVE

Sleep is vital for normal cognitive function in daily life, but is commonly disrupted in older adults. Poor sleep can be detrimental to mental and physical health, including cognitive function. This study assessed the association between self-reported short (<6 h) and long (>9 h) sleep duration and sleep fragmentation (3≥ nightly awakenings) in cognitive function.

METHODS

Cross-sectional data from 8508 individuals enroled in the PROTECT study aged 50 and above formed the basis of the univariate linear regression analysis conducted on four cognitive outcomes assessing visuospatial episodic memory (VSEM), spatial working memory, verbal working memory (VWM), and verbal reasoning (VR).

RESULTS

Short (ß = -0.153, 95% CI [-0.258, -0.048], p = 0.004) and long sleep duration (ß = -0.459, 95% CI [-0.826, -0.091], p = 0.014) were significantly associated with poorer cognitive performance in VWM. Long sleep duration (ß = -2.986, 95% CI [-5.453, -0.518], p = 0.018) was associated with impaired VR. Short sleep (ß = -0.133, 95% CI [-0.196, -0.069], p = <0.001) and sleep fragmentation (ß = -0.043, 95% CI [-0.085, -0.001], p = 0.043) were associated with reduced VSEM. These associations remained significant when including other established risk factors for dementia and cognitive decline (e.g., depression, hypertension).

CONCLUSIONS

Our findings suggest that short and long sleep durations and fragmented sleep, may be risk factors for a decline in cognitive processes such as working memory, VR and episodic memory thus might be potential targets for interventions to maintain cognitive health in ageing.

Association between sleep health and intrinsic capacity among older adults in Taiwan

Although the association between poor sleep quality and frailty has been previously reported, the relationship between sleep health and intrinsic capacity (IC) remains largely unknown. We aimed to examine the association between sleep health and IC among older adults. This was a cross-sectional study, and 1268 eligible participants completed a questionnaire collecting information on demographic, socioeconomic, lifestyle, sleep health, and IC. Sleep health was measured by the RU-SATED V2.0 scale. High, moderate, and low levels of IC were defined using the Integrated Care for Older People Screening Tool for Taiwanese. The ordinal logistic regression model estimated the odds ratio and corresponding 95% confidence interval. Low IC was significantly associated with age of 80 years or above, female, currently unmarried, uneducated, currently not working, financially dependent, and having emotional disorders. A one-point increase in sleep health was significantly associated with a 9% reduction in the odds of poor IC. An increase in daytime alertness was related to the greatest reduction in poor IC (aOR, 0.64; 95% CI, 0.52-0.79). In addition, the subitems sleep regularity (aOR, 0.77; 95% CI, 0.60-0.99), sleep timing (aOR, 0.80; 95% CI, 0.65-0.99), and sleep duration (aOR, 0.77; 95% CI, 0.61-0.96) were associated with a reduced OR of poor IC but with marginal statistical significance. Our findings showed that sleep health across multiple dimensions is related to IC, particularly daytime alertness in older adults. We suggest developing interventions to improve sleep health and prevent IC decline, which is crucial in causing poor health outcomes.