Greater amounts of REM sleep are linked to significantly lower risks of dementia, Parkinson’s disease, and other health conditions, according to a major study involving over 95,000 adults.
A recent study has revealed that increased rapid eye movement (REM) sleep is associated with a substantially reduced risk of various diseases, including dementia and Parkinson’s disease. The research, which tracked over 95,000 adults, found that greater REM sleep correlated with an 80% lower risk of developing Parkinson’s and a 46% lower risk of dementia.
The study, conducted by researchers in China, involved participants who wore wrist accelerometers continuously for seven days and nights. The data collected was analyzed using deep-learning algorithms to assess different sleep stages, including REM sleep, deep sleep, light sleep, total sleep duration, wakefulness after sleep onset, and sleep irregularity. Health records were then examined to identify associations with more than 1,000 diseases over a follow-up period of nearly nine years.
In addition to the significant findings regarding REM sleep, the study also noted that greater amounts of deep sleep were linked to lower risks of seven specific health conditions, including Type 2 diabetes and major depressive disorder. The researchers highlighted that sleep duration plays a critical role in health outcomes, identifying six to eight hours of sleep per night as the “sweet spot” associated with the lowest risk for 69 diseases. Conversely, sleeping less than five hours per night was associated with an increased risk of 37 health conditions.
The study further revealed that irregular sleep patterns and increased wakefulness during the night were associated with higher risks of various conditions, including anxiety and substance use disorders. These findings were published on September 17 in the journal PLOS Medicine.
Dr. Oki Ishikawa, a pulmonary, critical care, and sleep medicine expert at Northwell’s Northern Westchester Hospital, emphasized the importance of both total sleep duration and the percentage of REM sleep. He noted that the average percentage of REM sleep in the study population was about 20%, which aligns with the normal range of 20-25% per sleep cycle. However, he cautioned that simply having a higher amount of REM sleep may not be sufficient to lower disease risk.
“Normal sleep patterns and duration are associated with aspects like maintenance of good immune function and memory,” Dr. Ishikawa stated. “The important message here is to try and get a sufficient amount of sleep in general.”
Dr. Chelsie Rohrscheib, a sleep expert at Wesper, pointed out that disrupted sleep may serve as an early warning sign of underlying diseases rather than just a consequence. She explained that conditions such as Parkinson’s disease, dementia, and heart failure can begin to affect sleep years before a formal diagnosis is made. Additionally, poor sleep may contribute to the progression of these diseases, indicating a bidirectional relationship.
Despite the promising findings, the researchers acknowledged several limitations of the study. As it was observational, the research could only establish associations rather than causation. The sleep data was collected over just one week using a wrist device, which is less accurate than clinical sleep studies for identifying specific sleep stages. Furthermore, some health information was gathered years earlier, and medications that could influence sleep were not fully accounted for. The study’s participants were drawn from the UK Biobank, which may limit the generalizability of the findings due to a less diverse and generally healthier population.
Dr. Rohrscheib concluded, “Overall, changes in sleep may provide important clues about underlying health, but this study cannot determine whether poor sleep is a cause, an early symptom, or both.” She also cautioned that while wrist-worn sleep trackers can estimate sleep stages, they are not 100% accurate.
Future research is needed to explore whether increasing REM or deep sleep can help prevent certain diseases and to investigate how the relationship between sleep stages and disease risk may vary by age, sex, overall health, and other individual characteristics.
Both Dr. Ishikawa and Dr. Rohrscheib recommend adhering to general sleep hygiene practices. These include maintaining an optimal sleep environment—dark, cool, and quiet—keeping a consistent sleep schedule, and avoiding substances like alcohol and caffeine that can disrupt sleep. Dr. Ishikawa added that addressing other sleep disorders, such as sleep apnea, could significantly enhance the amount of REM sleep a person achieves.
Ultimately, while measuring REM sleep can be challenging without specialized equipment, Dr. Ishikawa suggested that a good indicator of sleep quality is whether one feels refreshed upon waking and does not experience daytime sleepiness. Achieving seven to nine hours of uninterrupted sleep is likely to provide sufficient opportunity for cycling through REM sleep.
According to Fox News, the implications of this study underscore the importance of prioritizing sleep for overall health and well-being.