REM Sleep Stage Linked To A Lower Risk Of 83 Diseases

You probably already know that getting enough good-quality sleep is important for health. It’s been linked to an additional four years of life and could even lower your dementia risk.

But what exactly about sleep, and which part of the process in particular, confers these benefits?

A new study published in PLOS One may have some answers. After looking at sleep and health data from 95,559 people, researchers found a link between REM sleep and a lower likelihood of developing dozens of health conditions.

Meanwhile, other stages, like deep sleep, seemed to matter too – just to a lesser extent. Sleep duration appeared to affect risk, as well.

REM, or rapid eye movement, sleep is an active stage of the sleep cycle in which most of our dreams occur.

Your heart rate, blood pressure, and even temperature can rise during this phase of sleep, and your eyes will – as the name suggests – rapidly move.

Harvard Health said muscles in the arms and legs “also become temporarily unable to move” during this stage to prevent you from acting out your dreams.

In the latest study, the authors compared a week’s worth of sleep data, which came from participants’ tracking watches, with later disease incidence almost nine years later.

Researchers discovered that “variations in sleep patterns were associated with 156 incidences of diseases”.

Spending more time in REM sleep was associated with lower odds of developing a whopping 83 diseases, including heart failure, multiple sclerosis, Alzheimer’s disease, hypotension (low blood pressure), and atrial fibrillation.

Meanwhile, those who got more deep sleep, which should make up about a quarter of your overall slumber, seemed less likely to go on to have seven conditions, including type 2 diabetes, sleep apnoea, depression, and Parkinson’s disease.

Greater sleep irregularity was linked to higher chances of developing three conditions (abdominal pain, anxiety, and depression), while waking up in the middle of the night seemed to increase the likelihood of six ailments (including psychoactive substance dependence and osteoarthritis).

And getting between six and eight hours of shut-eye a night was associated with a lower risk of developing 69 diseases; those who kipped for fewer than five hours seemed likelier to face 37 health issues.

“These findings highlight that both sleep architecture and sleep duration are associated with disease risk,” the study said.

This doesn’t prove for sure that either REM sleep duration or overall sleep patterns definitely caused the higher risk profiles for these diseases. They just showed an association.

The study authors said this could be an example of “reverse causation”, too, meaning the condition creates the sleep difference rather than the other way around.

But the paper ended: “The findings underscore that maintaining 6–8 hours of sleep is associated with a more favourable sleep architecture and lower disease risk, offering insights for prevention and health promotion.”

Responding to the study, Dr Greg Elder, Associate Director of Northumbria Centre for Sleep Research at Northumbria University, highlighted some of the limitations of the study – one being that movement-based watches “can’t yet accurately determine what sleep stage we are actually in overnight”.

“I think this research is good quality because it adds to the increasing number of studies that show that how much sleep we actually objectively get, and not just how much sleep we say that we get (which is often different), is very important from a health perspective,” he added.

Dr Elder ended: “This study adds to the evidence to show that a regular sleep pattern, where we get enough sleep, is important for our physical and psychological health, as we get older.”

Dr Nina Rzechorzek, a clinician scientist at the University of Cambridge, said the results “support sleep patterns as potentially informative markers of future disease risk”.

That said, “they do not show that increasing REM or deep sleep, or simply forcing sleep into a 6–8-hour window, will prevent disease”.