When you open your sleep tracker tomorrow morning, skip the sleep score and turn your attention to another number. A recent study has found time spent in REM sleep is a vital metric for understanding your longevity and illness risk — and most sleep trackers measure it.
A 2026 survey published in PLOS Medicine analyzed data from over 95,000 people wearing a sleep trackers. The researchers linked increased amounts of Rapid Eye Movement (REM) sleep with a lower risk of 83 conditions, including heart failure and dementia.
You might overlook REM in favor of juicier metrics like deep sleep and 3 a.m. wake ups, but this sleep stage is essential for your wellbeing. We asked sleep experts Dr. Hana Patel and Dr. Hanul Bhandari, what we need to know about REM sleep, including how to get more of it.
What is REM sleep — and why do you need it?
“REM sleep, (Rapid Eye Movement), is the fourth and final stage of sleep," explains Dr. Patel, NHS GP and resident sleep expert for Time4Sleep. "While this stage tends to be best known for vivid dreaming, it’s also essential for brain development, memory, and emotional regulation."
"REM sleep is characterized by abundant rapid eye movements, high-frequency EEG signals similar to those during alert waking periods, and other polysomnographic indicators," explains Dr. Bhandari, MD.
REM should account for 20-25% of your sleep, or around 90 to 120 minutes (assuming a seven hour total sleep time.) But REM sleep often gets cut short because of when it occurs in your sleep cycle.
"The length of REM stages can last for different durations but the periods increase as the night progresses," explains Dr. Bhandari. "As the sleep progresses through the night, a greater fraction of each cycle is spent in REM sleep."
That means waking up early cuts down time in REM.
Dr. Patel warns this disruption is associated with a worse mood and can contribute to "chronic stress, anxiety, and depression."
Dr. Bhandari also notes that studies have linked a lack of REM sleep to "higher mortality." However, he adds that increasing the amount of time spent in the REM stage isn't a simple fix for a longer life — your sleep is more complex than that.
How to find REM sleep on your sleep tracker
Most of the best sleep trackers divide sleep into three key stages: light sleep (or core sleep), REM sleep, and deep sleep. How long you spent in each stage and overall sleep duration are typically combined to create your sleep score.
Dr. Patel explains that REM sleep is characterized by "increased brain activity, darting eye movements, limited muscle movement, and fluctuating heart and respiration rates." It's these metrics your sleep tracker observes and uses to determine when you're in that REM stage.
You can typically see your REM sleep in two ways. First, as a graph, which shows when in the night REM sleep occurred. This helps you understand if you're waking up before the increased REM associated with the latter stages of sleep (and if your alarm is blaring you awake in REM stage.)
Second, you can view it as a duration, combining all the different moments of REM sleep during the night. It's an easy way to see if you racked up enough REM sleep, and to compare it to other sleep stages.
How to get more REM sleep
If your sleep tracker is putting your REM sleep in the red, it's time for a sleep quality audit.
“To increase REM sleep, you’ll need to increase your overall sleep duration, explains Dr. Patel. "The NHS recommends that the average adult needs seven to nine hours of sleep every night."
"Start by protecting the latter part of the sleep period," adds Dr. Bhandari, "because REM sleep becomes more concentrated as the night progresses."
Both recommend practicing good sleep hygiene, to help you stay asleep for longer and avoid the 3 a.m. wake ups that can cut your sleep cycles short.
- "Keep regular waking times and bedtimes," says Dr. Patel. Dr. Bhandari explains this helps "promote a stronger sleep-wake cycle," which can increase your overall sleep duration.
- "Try to work out exactly how much sleep you need," Dr. Patel recommends, "so you can sleep enough so as not to need an alarm clock to wake in the morning."
- "Maintain a comfortable, quiet sleeping environment at the right temperature," advises Dr. Patel. Our best mattress guide can help you get started.
- "Avoid caffeine in the afternoon and keep the amount low in the morning," says Dr. Patel. She also recommends cutting out alcohol before bed.
- "Practice psychological relaxation techniques prior to sleep," says Dr. Patel. Guided sleep meditations are an accessible option.