In general, you need less sleep as you age, including slightly less REM. But large deficits of REM sleep, no matter your age, can deprive you of its psychological benefits, Dr. Dasgupta said. You may have more trouble learning, processing emotional experiences or solving problems.
Dysregulated REM sleep is also linked with cognitive and mental health issues, like slower thinking and depression, said Dr. Ana Krieger, medical director of the Center for Sleep Medicine at Weill Cornell Medicine. Too little REM, fragmented REM and REM sleep behavior disorder — where muscle paralysis fails to happen and people physically act out their dreams, often by kicking or punching — are associated with neurological issues, from mild forgetfulness to dementia and Parkinson’s disease.
A 2020 study of over 4,000 middle-aged and older adults found that each 5 percent decrease in REM sleep was linked with a 13 percent greater risk of dying from any cause over the next two decades. Lack of sleep in general is associated with death, but the research suggests that not getting enough REM sleep “is the single strongest factor of all stages,” Dr. Walker said.
Dr. Walker and other experts aren’t sure what to make of this relationship between REM sleep and mortality. “I don’t think we understand REM sleep well enough yet to definitively say which mechanisms are at play,” he said. Or, as Dr. Gurubhagavatula said, if lack of REM is actually causing death.
How do you know if you need more?
It is hard to tease apart signs of REM sleep deficiency from signs of overall sleep deprivation, Dr. Gurubhagavatula said. If you’re sleep-deprived, then you’re probably REM-deprived.
Certain behaviors, however, can specifically compromise your REM sleep. “Cutting your sleep short by going to bed late and then using an alarm clock to wake up can put you at risk for chronic deprivation of REM sleep,” Dr. Gurubhagavatula said. That’s because the longest REM periods often happen at the end of the night.
Having an alcoholic drink before bed also “markedly impairs your REM sleep,” Dr. Walker said, because the process of metabolizing alcohol produces compounds that affect sleep cycle regulation. What’s more, Dr. Gurubhagavatula explained, moderate and heavy drinkers have a higher risk of REM sleep behavior disorder.
