Quality of Sleep Linked to Risk Reduction in Various Diseases

A recent study highlights the influence of different sleep types on the risk of developing over 80 diseases. Researchers from Peking University and Capital Medical University in Beijing found that more REM sleep—where most dreaming occurs—at night is linked to a reduced risk of 83 diseases. Greater deep sleep, known for its restorative properties, is associated with a lower risk of seven diseases. These findings were published in the journal PLoS Medicine on September 17.

Understanding REM and Deep Sleep

REM sleep involves rapid eye movements, even when eyes are closed, and is crucial for cognitive functions. It supports emotional regulation, brain development, mental health, and enhances learning and memory. Conversely, deep sleep is characterized by significantly reduced brain activity. This stage facilitates tissue repair and the removal of metabolic waste among other essential functions.

Study Observations

The study analyzed data from wrist accelerometers worn by over 95,000 U.K. Biobank participants. After a week of wearing these devices, participants were monitored for a median of 8.9 years for health conditions or mortality. Increased REM sleep duration was linked to a lower risk of diseases like heart failure, Parkinson’s disease, and Alzheimer’s. Deep sleep was associated with lower risks of type 2 diabetes, major depressive disorder, sleep apnea, and Parkinson’s.

However, the researchers caution that some associations might result from ‘reverse causation.’ For instance, symptoms of depression could alter sleep patterns rather than vice versa. The study also found that longer light sleep duration could increase the risk of conditions like depression but reduce risks of heart failure. The researchers concluded that those sleeping six to eight hours nightly had the best health outcomes.

Expert Insights

Eve Van Cauter from the University of Chicago emphasized that sleep is essential for health, and deficiency can lead to illness. Girardin Jean-Louis of the University of Miami added that sleep architecture and regularity are crucial for understanding sleep health. He notes a limitation of the study in that it uses wrist accelerometry instead of polysomnography for precise measurements.

While the study reveals essential associations, it doesn’t confirm that altering sleep stages will definitely prevent diseases. Future research should replicate findings in diverse groups and identify specific causal pathways.

Impact of Sleep on Health

Van Cauter mentioned that sleep is part of the Earth’s 24-hour rotation adaptation, affecting all physiological aspects. In the brain, sleep aids neuronal recovery and waste removal. Nour Makarem of Columbia University noted poor sleep links to hormonal imbalances, weight gain, and heart disease. Poor sleep also increases stress, inflammation, and disrupts circadian rhythms, predisposing individuals to diseases.

For improved health outcomes, Makarem suggests pragmatic interventions promoting sleep health alongside diet and exercise. Van Cauter advocates for sleep education beginning in kindergarten and advancing through high school.