Nonlinear relationships between sleep duration, mental health, and quality of life: The dangers of less sleep versus more sleep

• Published in: Sleep medicine 2024-07, Vol.119, p.565-573
• Main Authors: Wang, Fei, Sun, Zhijing, Lin, Feng, Xu, Yanni, Wu, Erya, Sun, Xinying, Zhou, Xiaoming, Wu, Yibo
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age Factors; Aged; China; Cross-Sectional Studies; Female; Humans; Male; Mental Health; Middle Aged; Nonlinear relationships; Quality of life; Quality of Life - psychology; Sleep - physiology; Sleep Duration; Surveys and Questionnaires; Time Factors; Young Adult
• ISSN: 1389-9457; 1878-5506; 1878-5506
• DOI: 10.1016/j.sleep.2024.05.043

Recent research has found a non-linear relationship between sleep duration and mental health/quality of life. However, it is currently unclear which age group is more affected by sleep duration and what the optimal sleep duration is for each age group. Additionally, the underlying mechanisms of the non-linear relationship between sleep duration and quality of life are not well understood. Therefore, this study utilized questionnaire data from 20,962 participants in the Chinese PBICR-2022 database(Cross-sectional study) and constructed models to analyze the relationship between sleep duration and quality of life. The results showed that the optimal sleep duration varied among different age groups: approximately 9 h for adolescents, 8 h for early/middle-aged adults, and 7 h for older adults. Compared to other age groups, less or more sleep duration had a greater impact on mental health and quality of life in adolescents. Furthermore, mental health was found to play a significant mediating role between sleep duration and quality of life in both the less sleep group and the more sleep group, but this mediating effect was not significant among the older adults in the less sleep group, whereas the mediating effect of mental health was not significant among the middle-aged adults in the more sleep group. This suggests that different age groups have different optimal sleep duration, and age may be an important factor influencing the relationship between sleep duration and mental health/quality of life, with mental health playing a mediating role in the relationship between sleep duration and quality of life. •The optimal sleep duration generally shows a decreasing trend with age.•Mental health and quality of life are more affected by insufficient or excessive sleep in adolescents.•Significant mediating effects were found in the “sleep duration-mental health-quality of life" model.•The mediating effect of sleep deprivation group in old age was not significant.•The mediating effect of sleep overdose group in mid-adulthood was not significant.