Researchers Found One Part Of REM Sleep Declines Faster In Women
On a good night, I clock somewhere between 1.5 and 2 hours of REM sleep. My dad, who's in his 70s, gets roughly half that. For a long time, I chalked it up to the fact that he's older and is a known light sleeper. That's, just how things go. Right?
Well new research1 that the quality, not just the quantity, of REM sleep changes across the lifespan. Here's what you need to know for your own sleep schedule.
Researchers set out to map how REM sleep changes across the adult lifespan
REM sleep (short for rapid eye movement sleep) is the stage most associated with vivid dreaming, emotional processing, and memory consolidation. But REM isn't one uniform state. It alternates between two phases: phasic and tonic.
- Phasic REM is the more active of the two, marked by bursts of rapid eye movements and heightened brain activity, and it's thought to be the phase most tied to memory and emotional processing.
- Tonic REM is quieter, with less eye movement and lower neural activity.
For this study, researchers wanted to understand how both phases shift as we get older, and whether that shift looks different in men versus women.
They used polysomnography (the gold-standard method for measuring sleep stages, which tracks brain waves, eye movements, and other physiological signals at once). They analyzed retrospective polysomnographic data from 627 healthy adults between the ages of 18 and 80.
REM sleep gets shallower with age, and women feel it first
Aging was linked to a broad decline in REM sleep. As people aged, the overall amount of REM sleep dropped, and so did the share of time spent in phasic REM specifically.
The number and density of rapid eye movements also declined with age, meaning the brain's activity during REM became less intense over time. Spectral analyses (which measure the frequency of brain-wave activity) showed that phasic REM slowed progressively across the lifespan, while tonic REM shifted toward higher-frequency activity.
Women showed a steeper decline in both phasic REM percentage and REM density compared with men, meaning the quality of their REM sleep dropped off faster with age. The researchers documented these differences in trajectory but didn't explain the mechanism behind them.
Why this matters for brain aging
The researchers frame this work as a step toward using REM sleep microstructure as a potential biomarker for neurodegenerative and psychopathological disorders. In plain terms, changes in the depth and complexity of REM sleep could one day help flag early signs of cognitive decline before other symptoms show up.
That aligns with what we research has already told us about phasic REM's role in the brain. The active, high-intensity phase is thought to be especially important for memory consolidation and emotional regulation. A gradual erosion of that phase (fewer eye movements, slower brain-wave activity, less time in the most restorative part of REM) could have downstream effects on how the brain functions over time.
How to protect your REM sleep as you age
You can't stop the natural changes that come with aging, but there are evidence-informed steps that support the quality of your sleep, including your REM sleep:
- Keep a consistent sleep schedule: Going to bed and waking up at the same time every day helps regulate your circadian rhythm, which supports healthy sleep architecture, including REM cycles.
- Limit alcohol, especially in the evening: Alcohol is one of the most well-documented REM suppressants. Even moderate amounts close to bedtime can cut into the amount and quality of REM sleep you get.
- Take a sleep supplement: A magnesium-based sleep supplement can be an effective solution for helping your brain and body relax before bed. This powder combines two form of magnesium with tart cherry extract to promote rest and recovery.
- Manage stress before bed: Elevated stress and cortisol can fragment sleep and reduce time in deeper sleep stages. A wind-down routine (light stretching, breathwork, or stepping away from screens) helps your nervous system downshift.
The takeaway
REM sleep quality (not just quantity) declines with age. Women appear to experience a steeper drop in the most active, restorative phase of REM sleep compared with men. So if you're still feeling tired after seemingly logging a good amount of REM sleep (or you feel energized after a short sleep duration), it could be the quality of your REM sleep at play.
