Insights into Sleep and Health

Sleep involves more than just the hours you spend snoozing; it encompasses various stages, each impacting our health in unique ways. A recent study published in PLOS Medicine, led by researchers from Capital Medical University in China, examined the sleep habits of 95,559 participants from a UK health initiative.

Utilizing wrist-worn trackers, they analyzed a week’s worth of sleep data in relation to over a thousand health conditions, with participants tracked for nearly nine years on average. One sleep phase that particularly stood out was REM (Rapid Eye Movement) sleep, the stage where most dreaming occurs.

During REM sleep, brain activity is similar to that when we’re awake, lending it a role in enhancing learning and brain development. The study highlighted that an increased amount of REM sleep linked to a reduced risk of numerous diseases, including heart failure, Alzheimer’s, hypotension, and atrial fibrillation.

“Our analysis identified variations in sleep patterns connected to 156 disease incidences,” the researchers noted. More specifically, they observed that greater REM and deep sleep correlated with lower risks for 83 and 7 different diseases, respectively. In contrast, irregular sleep patterns and waking up after initially falling asleep were tied to higher risks of 3 and 6 diseases, respectively.

For deep sleep, their findings suggested connections to lower risks for type 2 diabetes and Parkinson’s disease. Interestingly, the researchers identified a ‘sweet spot’ for sleep between six and eight hours per night, which seemed to lower the risks for a considerable number of diseases. In fact, getting less than five hours was associated with a higher risk of 37 diseases compared to the six-to-eight hours range.

What’s more, they examined the proportion of REM sleep relative to total sleep time, indicating that the benefits observed weren’t merely the result of longer sleep durations. “These findings emphasize that both the structure of sleep and the amount of sleep are crucial for disease risk,” the researchers stated.

Although more research is necessary, they suggest that REM sleep may influence biological pathways distinct from general sleep, providing varied benefits and interacting with diseases differently. While we know sleep aids bodily rest and allows the brain to recharge, deepening our understanding of REM sleep will be pivotal for future studies.

This study offers a fresh framework for comprehending how sleep patterns relate to health risks, although it stops short of proving direct cause-and-effect relationships. The study’s strength lies in its large participant pool and reliance on real-life sleep data instead of self-reported measures.

Throughout a night, we cycle through multiple sleep stages, and two significant factors determining our REM sleep are the total quantity of sleep and how uninterrupted it is. Disrupting our circadian rhythm, along with factors like stress and alcohol consumption, can negatively affect REM sleep, which also tends to decrease naturally as we age.

Despite knowing a fair bit about sleep, the complexities of REM—like why warmer animals may experience less of it—remain somewhat mysterious. Clearly, though, its role is vital for our health. So, it might be worth considering that extra hour in bed tonight.

“Our findings indicate that keeping to 6–8 hours of sleep is linked to favorable sleep patterns and reduces disease risks, providing essential insights for health promotion,” the researchers concluded.

The full study can be found in PLOS Medicine.