Not all sleep is created equal, and according to a massive new study, the specific stages of your nightly rest could play a significant role in whether you develop certain illnesses. Researchers from Peking University and Capital Medical University discovered that increasing the amount of REM sleep, the phase characterized by vivid dreams and rapid eye movement, is linked to a lower risk of 83 different diseases. These include serious conditions such as heart failure, multiple sclerosis, dementia, and Alzheimer’s disease. While deep sleep is often praised as the most physically restorative stage, it was associated with a lower risk for only seven diseases, including type 2 diabetes and major depressive disorder.
To reach these conclusions, scientists analyzed data from over 95,000 participants in the UK Biobank who wore wrist accelerometers for a week. The team tracked these individuals for nearly nine years to see how their sleep patterns correlated with subsequent health outcomes. They found that people who averaged between six and eight hours of sleep per night generally exhibited the healthiest patterns and the lowest disease risks. However, the researchers cautioned that reverse causation might be at play in some cases; for instance, depression often disrupts sleep patterns, meaning the illness might cause the poor sleep rather than the other way around.
Medical experts suggest these findings reinforce the idea that sleep is a fundamental pillar of health alongside diet and exercise. Nour Makarem of Columbia University noted that insufficient or fragmented sleep can lead to hormonal imbalances and chronic inflammation, creating a pathway toward cardiometabolic and neurodegenerative issues. By facilitating the removal of metabolic waste from the brain and helping regulate emotions through REM cycles, quality sleep acts as a critical maintenance system for both the mind and body.
Despite the impressive scale of the study, some specialists urge caution regarding how we track our rest. Girardin Jean-Louis from the University of Miami pointed out that using wearable devices to estimate sleep stages lacks the precision of clinical polysomnography, which remains the gold standard in medicine. While wearables are excellent for studying large groups, they cannot definitively prove that increasing a specific stage of sleep will prevent a disease. Future research will likely focus on more diverse populations to determine if these sleep patterns are truly causing better health or simply serving as early warning signs of disease development.
