Is Sleep Quality in Decline?

Check out this answer from Consensus:

The evidence suggests that while sleep quality tends to decline with age, the majority of people maintain good sleep quality throughout their lives. Poor sleep quality is strongly associated with cognitive decline and functional limitations, particularly in older adults. However, the notion that sleep duration has significantly declined over the past few decades is not supported by recent objective data. Factors such as stress, depression, and physical health play crucial roles in determining sleep quality. Addressing these factors may help mitigate the decline in sleep quality and its associated health impacts.

The question of whether sleep quality is in decline is of significant interest due to its implications for public health, cognitive function, and overall well-being. Various studies have examined trends in sleep quality over time and its association with cognitive decline and other health outcomes.

Key Insights

• Association Between Poor Sleep Quality and Cognitive Decline:
  • Poor sleep quality is linked to cognitive decline in older adults, with studies showing that individuals with poor sleep quality are more likely to experience significant cognitive decline over time1 2 3 5 6 7.
  • Specific aspects of poor sleep, such as reduced sleep efficiency, greater nighttime wakefulness, and short sleep duration, are particularly associated with cognitive decline1 3 6.
• Sleep Quality and Age:
  • Sleep quality tends to decline with age, with a higher proportion of older adults reporting poor sleep quality compared to younger adults4 6.
  • Longitudinal studies indicate that while the majority of people maintain good sleep quality, a significant minority experience a decline in sleep quality as they age4.
• Impact of Poor Sleep Quality on Functional and Cognitive Health:
  • Poor sleep quality is associated with subjective cognitive decline and related functional limitations, affecting both younger and older adults2 5.
  • Sleep disturbances and poor sleep quality are early indicators of cognitive impairment and are linked to conditions such as mild cognitive impairment (MCI) and Alzheimer’s disease (AD)6 7.
• Trends in Sleep Duration:
  • Contrary to the common belief that sleep duration has declined over the past few decades, recent reviews and studies have found no significant reduction in objectively recorded sleep duration over the last 50+ years8 9.
• Factors Influencing Sleep Quality:
  • Sleep quality is influenced by a range of factors including age, stress, depression, physical health, and environmental conditions4 10.
  • Poor sleep quality has significant adverse health outcomes, including increased fatigue, irritability, and daytime dysfunction10.

Is sleep quality in decline?

Panagiotis Matsangas has answered Uncertain

An expert from Naval Postgraduate School in Sleep Research

Sleep quality is affected by multiple factors, to include the quality the environment the individual sleep in, stress, age, pathological issues, whether the individual splits sleep in multiple sleep episodes due to extraneous factors. The association between the above mentioned factors and sleep is (in general) known. The impact on sleep quality may differ between individuals and within each individuals between different time periods. Therefore, a systemic decline in sleep quality due to these factors is not supported by existing research.

Sleep, however, is affected also by exposure to light before sleep (and in some cases during sleep as well). Specifically, being exposed to bright light (especially blue light) before sleep has been associated with difficulty sleeping (for example, Komada et al. 2000), curtailed sleep duration and self-perceived insufficient sleep (Suganuma et al. 2007; Fossum et al. 2014). In general, sleep hygiene practices recommend exposure to light based on our internal biological clock. Assuming a healthy individual working normal hours (not a shift worker), natural light during daytime and darkness at nighttime is recommended. Therefore, it is expected that exposure to artificial light at times not aligned with our body clock will affect our sleep. Along these lines, the use of light emitting devices before sleep will affect the sleep of individuals who exercise this practice.