Sleep and heart disease are linked. In large studies, people who regularly sleep too little have more coronary heart disease and stroke, and so do people who sleep unusually long. Newer research suggests that keeping irregular hours carries risk as well.
Nearly all of this evidence is observational. It shows that poor sleep and heart disease travel together, not that one causes the other, and no large trial has shown that sleeping longer prevents heart attacks. Sleep is still worth taking seriously, because it affects blood pressure, weight and blood sugar.
Key takeaways
- Since 2022 the American Heart Association has counted sleep as one of eight core measures of heart health.
- Both short and long sleep are tied to more heart disease and stroke, and long sleep is probably a sign of other illness.
- Bedtimes and sleep lengths that swing widely from night to night were linked to more cardiovascular events in one well-known US study.
- These are associations from observational research, so they cannot prove that better sleep will protect your heart.
Why sleep is now on the heart-health checklist
For years the American Heart Association summed up heart health with seven measures, known as Life's Simple 7. In 2022 it updated the list and renamed it Life's Essential 8. The eight components are diet, physical activity, nicotine exposure, sleep health, body mass index, blood lipids, blood glucose and blood pressure, with sleep health as the new addition.1
A 2016 scientific statement from the same association had already reviewed that research and called on health organizations to include sleep recommendations in their guidance.2
Sleep duration: too little and too much
The most quoted numbers come from a meta-analysis of 15 prospective studies with 474,684 participants, followed for between 7 and 25 years. Compared with people who slept a middle amount, short sleepers had a 48% higher risk of developing or dying from coronary heart disease and a 15% higher risk of stroke.3
Long sleepers were not better off. Long sleep was associated with a 38% higher risk of coronary heart disease and a 65% higher risk of stroke.3
| Sleep pattern | Coronary heart disease | Stroke |
|---|---|---|
| Short sleep | 48% higher risk | 15% higher risk |
| Long sleep | 38% higher risk | 65% higher risk |
Sleep was reported by questionnaire, and each study drew its own line for "short" and "long". The authors described both as predictors, or markers, of cardiovascular outcomes.
Long sleep in particular is unlikely to harm the heart directly. People often sleep more because something else is wrong, such as depression, chronic illness, pain or an undiagnosed sleep disorder. In that case the long sleep is a signal, not the cause.
This article does not give a target number of hours, because the right amount varies somewhat from person to person. If you regularly wake unrefreshed or struggle to stay awake during the day, raise it with your clinician whatever the clock says.
Regular timing matters too
How consistent your sleep is may matter apart from how long you sleep. The clearest evidence comes from MESA, a long-running US study of adults from several ethnic backgrounds.
In MESA, 1,992 adults without cardiovascular disease wore a wrist tracker for seven days and were then followed for a median of 4.9 years. People whose sleep length varied the most from night to night had about twice the risk of a cardiovascular event as people with the most consistent sleep.4 The result was similar for people whose bedtime shifted the most.
The link held after the researchers accounted for average sleep length and for standard risk factors. It also held when shift workers were left out.
There are limits. Only 111 events occurred during the study, so the estimates are imprecise. One week of tracking may not reflect years of habit. And irregular sleep often goes with irregular work, caregiving or stress, which bring risks of their own.
How poor sleep might raise heart risk
Researchers have proposed several routes, and the 2016 statement reviewed them. Short sleep and sleep disorders have been related to obesity, high blood pressure, type 2 diabetes and cardiovascular disease.2
The suggested pathways are:
- Blood pressure. Blood pressure normally dips at night. Short or broken sleep cuts into that rest period.
- Appetite and weight. People who sleep too little tend to eat more and move less the next day.
- Blood sugar. Short sleep has been related to type 2 diabetes, which develops through insulin resistance.
- Inflammation and stress hormones. Both are being studied as links between sleep and artery disease. Our guides to inflammation and stress cover them.
These pathways are plausible. They do not yet add up to proof that fixing sleep lowers the rate of heart attacks.
What the evidence cannot tell you
Three questions are still open.
First, cause and effect. Early heart disease, depression and other illnesses can disturb sleep years before they are diagnosed, which can make poor sleep look like a cause when it is partly a result.
Second, treatment. We do not have large trials showing that helping people sleep longer or more regularly reduces heart attacks or strokes.
Third, sleep aids. Nothing here supports taking sleeping pills or supplements for the sake of your heart. That is a conversation for your prescriber.
When poor sleep points to something else
Sometimes the problem is not your habits. Loud snoring, pauses in breathing that a partner notices, waking up gasping, morning headaches and heavy daytime sleepiness can be signs of obstructive sleep apnea. That condition has its own links to blood pressure, heart rhythm problems and cardiovascular events, and its own treatment evidence. We cover it separately in sleep apnea and heart risk.
Where to go from here
Sleep is one input into heart risk. Our guide to the PREVENT risk calculator shows how blood pressure, cholesterol and blood sugar combine into a 10-year estimate, and the heart disease risk assessment guide explains what a fuller evaluation includes.
Cardio Res-Q, the heart-disease prevention program at YoungerMeMD, asks about sleep quality as part of its lifestyle and risk evaluation. The screener on the program page has three quick questions to help you see whether a closer look fits your situation.
Are You a Candidate for Cardio Res-Q?
Three quick questions about the risk factors we screen for. Your answers stay between you and the clinic.
Frequently asked questions
Does poor sleep cause heart disease?
It is linked to heart disease, but cause has not been proven. People who sleep too little or keep irregular hours have more cardiovascular events in observational studies, and there are plausible biological reasons. Other illnesses can also disturb sleep, so some of the link runs the other way.
Is sleeping a lot bad for my heart?
Long sleep is associated with more heart disease and stroke, but it is probably a marker of other health problems and not harmful in itself. If you have started needing much more sleep than you used to, mention it to your clinician.
Does it matter if I go to bed at different times?
It may. In the MESA study, people with the most irregular sleep had about twice the rate of cardiovascular events of people with the steadiest sleep. That was one study with a small number of events, so treat it as a reason to keep a reasonably steady routine, not as a precise risk figure.
Related reading
This article is for general education and is not medical advice. Decisions about testing and medication should be made with your clinician. If you have chest pain or other symptoms of a heart attack, call 911.
