Are naps good for you? What the research on daytime napping shows

Short naps have a good reputation and long ones a bad one. The research mostly agrees, but it also shows why a long nap can be a sign of a problem rather than a cause of one.

An older man napping on a sofa under a blanket, with a glass of water in the foreground.

Summary

A pooled analysis of 11 studies and 151,588 people linked naps of an hour or more to higher heart disease risk.
Naps under an hour were not linked to higher risk, and risk dipped slightly with naps up to about 30 minutes.
Long daytime napping can be a sign of poor night sleep, sleep apnea or illness, which muddies the link.
Genetic studies suggest a habit of napping goes with a slightly larger brain volume.
The same genetic approach linked napping to higher type 2 diabetes risk, so the picture is mixed.

In some countries an afternoon nap is a tradition; in others it is a guilty pleasure. The science has swung between the two views, with headlines linking naps to both sharper brains and earlier death.

Most of the research agrees on a simple pattern. Short naps, under about half an hour, are not linked to harm and may go with slightly lower heart risk. Long naps, an hour or more, are linked to higher risk of heart disease and death. The catch is that a long nap is often a symptom of something else, which makes it hard to know whether napping itself is to blame.

What the napping studies measure

Most napping research asks people how often and how long they nap, then follows them for years. For a pooled analysis in the journal SLEEP, eleven prospective cohort studies were identified with 151,588 participants. They were followed for an average of 11 years, during which there were more than 5,000 heart and stroke events and nearly 19,000 deaths.

Sleep needs set the backdrop. MedlinePlus notes that it is a myth that older adults simply need less sleep: some people think adults need less sleep as they age, but there is no evidence to support this. Naps are often how people make up for sleep they are not getting at night. That matters for reading the studies: a person who naps for two hours may be doing so because their night sleep is short or broken, and that underlying problem can carry its own risks.

Are long naps linked to heart disease and death?

Yes. In the pooled analysis, a long daytime nap (≥ 60 min/day) was associated with a higher risk of cardiovascular disease compared with not napping, about 82% higher, and with about 27% higher risk of death.

The link followed a J-shaped curve. Heart risk dipped slightly for naps up to about 30 minutes, rose a little around 45 minutes, then climbed sharply for longer naps. Naps shorter than an hour were not linked to higher risk of heart disease or death. The authors caution that further studies are needed to confirm the efficacy of a short nap, so the small dip is not proof that short naps protect the heart.

Why long naps might be a warning sign

Long daytime sleep is often a result rather than a cause. People who sleep poorly at night, have untreated sleep apnea, depression or heart failure, or are becoming frail tend to nap more. Studies can adjust for known illnesses, but not for conditions that have not yet been diagnosed.

That is why researchers have turned to genetic methods. A method known as Mendelian randomization, named after the pioneer of genetics Gregor Mendel, uses genetic variants that make people more likely to nap as a kind of natural experiment, because genes are fixed at birth and are not changed by later illness.

What genetic studies suggest about naps and the brain

A 2023 study in Sleep Health used this method in UK Biobank, a large study of middle-aged British adults. With up to 378,932 participants, it found evidence consistent with a modest causal association between habitual daytime napping and larger total brain volume. It found no effect on reaction time, visual memory or the size of the hippocampus, a region important for memory.

A 2022 genetic study pointed the other way for metabolism. It reported that genetically predicted self-reported daytime napping was linked to higher risk of type 2 diabetes, along with insomnia and short sleep. Daytime sleepiness, which is different from choosing to nap, was linked to higher heart disease risk. Taken together, the genetic studies suggest napping is neither clearly good nor clearly bad.

What official sleep resources say about naps

MedlinePlus explains that sleep deprivation does more than make people tired, affecting mood and physical health. Its tips for shift workers include naps, to take naps and extend your total sleep time, and its general sleep tips advise against napping after 3 p.m., when a nap may make it harder to fall asleep at night.

Those tips treat naps as a tool for making up lost sleep, not as a replacement for regular night sleep.

What the napping research cannot tell us

Almost all napping data come from people’s own reports, which are often inaccurate about how long they actually slept. The pooled studies were mostly from Asia and Europe, where napping habits differ.

Genetic studies avoid some of these problems but rely on assumptions that are hard to test, and the genes linked to napping also influence other sleep traits. No large randomized trial has tested whether adding or cutting naps changes heart disease, dementia or diabetes risk.

What the napping evidence adds up to

The research supports a cautious reading. Short naps are not linked to harm, and there are hints of benefit that remain unproven. Long, regular naps go with higher risk, but much of that link probably reflects underlying sleep problems or illness.

A change in napping habits, such as suddenly needing long daytime sleep, is the kind of thing sleep specialists look into, because it can point to a problem with sleep at night.