A greater amount of REM sleep is linked to a lower risk of 83 different conditions, including heart failure, Alzheimer's disease, hypotension and atrial fibrillation, a new study published in PLOS Medicine shows.
Researchers at Capital Medical University in China analysed data from 95,559 participants in the UK Biobank. Sleep patterns were monitored over a week using a wrist-worn device, and sleep data were compared with more than a thousand health outcomes. Participants were followed for a median of almost nine years.
The REM stage is the phase during which we dream most and in which brain activity is similar to that in the wakeful state. It is believed to aid learning and brain development. The results showed that the positive association with REM sleep was not simply a result of longer sleep.
In addition to REM sleep, other sleep characteristics were found to be significant. Different sleep characteristics were associated with 156 health outcomes. More deep sleep was associated with a lower risk of seven conditions, including type 2 diabetes and Parkinson's disease. Sleeping for six to eight hours a night was associated with a lower risk of a significant number of conditions, and maintaining sleep in this range was associated with a more favourable sleep architecture and a lower risk of disease.
On the other hand, certain sleep patterns carry a higher risk. Sleeping for less than five hours a night was associated with a higher risk of 37 conditions. An irregular sleep pattern was associated with a higher risk of three conditions, and frequent waking after falling asleep was associated with a higher risk of six conditions.
Two key factors influencing the amount of REM sleep are total sleep duration and its continuity. Disruptions to the natural body rhythm, stress and alcohol can negatively affect the amount of REM sleep, and the amount of REM sleep naturally decreases with age.
The study does not demonstrate a direct causal link, the authors note.
