A recent study in BMC Public Health examined how the duration of midday naps and nighttime sleep affects mild cognitive impairment (MCI) in older Chinese adults. The research found that both short and long durations of nighttime sleep, as well as naps longer than 30 minutes, are associated with a higher risk of MCI. Optimal cognitive function is linked to about seven hours of nighttime sleep and naps shorter than 30 minutes.
Background Cognitive impairment, a major public health issue, affects quality of life, increases dependency, and burdens caregivers. With a growing elderly population in China, understanding factors that contribute to cognitive decline is crucial. Previous research has shown that both insufficient and excessive sleep can lead to cognitive problems.
About the Study The study analyzed data from the 2020 China Health and Retirement Longitudinal Study (CHARLS). Researchers selected 7,880 participants aged 60 and older. After excluding those with incomplete data, 5,314 participants remained. Cognitive function was evaluated through face-to-face assessments, and MCI was defined as scoring below age-specific norms.
Sleep duration was reported by participants, and sociodemographic, health, and lifestyle factors were considered. Statistical analyses, including logistic regression models, examined the relationship between sleep patterns and MCI.
Findings Among the participants, those who slept between six and eight hours per night had the lowest MCI rates. Those sleeping more than eight hours had the highest rates. Participants taking naps shorter than 30 minutes also showed lower MCI rates compared to those who did not nap.
The study revealed a U-shaped relationship between sleep duration and MCI risk: both inadequate and excessive sleep were linked to higher MCI likelihood. Optimal sleep included around 60 minutes for naps and six to eight hours for nighttime sleep.
Conclusions This study is the first to use a large, nationally representative dataset to explore how sleep duration affects MCI in elderly Chinese adults. It found that both too little and too much sleep increase MCI risk, emphasizing the need for balanced sleep patterns to protect cognitive health.
While the study provides valuable insights, limitations include reliance on self-reported sleep data and a cross-sectional design, which does not establish causality. Future research should involve longitudinal studies and objective sleep measurements to further clarify the relationship between sleep and cognition.
