We all know that an occasional night of little sleep makes for a difficult day of grogginess, fuzzy thinking, and mood swings. You might also know that regularly skimping on sleep makes symptoms worse and leads to stress and weight gain. But many people are unaware that insufficient sleep also poses dangerous health risks, especially for your heart.

How much sleep is too little?

Research shows the average person needs seven to nine hours of sleep per night. That can be difficult to achieve as we age, when it’s common to sleep a little less than seven hours per night. But if you’re getting less than six hours per night, your health is in jeopardy.

For example, a large analysis published online May 27, 2025, by the American Journal of Lifestyle Medicine, tied chronic sleep deficiency to high blood pressure, coronary artery disease, stroke, diabetes, obesity, mental health disorders, and even premature death. Other studies have linked chronic sleep deficiency to nearly three times the risk of heart disease (if you have several sleep problems) and a 20% higher incidence of heart attacks.

Why does it hurt the heart?

Insufficient sleep isn’t necessarily a direct cause of heart and vascular problems. It triggers a long list of physiological and hormonal changes — such as increases in blood pressure, blood sugar, and inflammation — that contribute to heart problems.

A lack of sleep also disrupts hormones that control hunger and appetite, often causing people to overindulge in foods rich in fat and carbohydrates — a quick path to weight gain.

Nationwide health surveys have found that people who average less than seven hours of sleep per night have higher rates of obesity, compared with those who get adequate amounts of sleep. Obesity is a major contributor to heart disease, chronic inflammation, and diabetes.

Change your sleep habits

If you’re not getting at least seven hours of uninterrupted sleep on most nights, consider your sleep habits. Are you waking up at the same time every morning? That’s essential to help anchor your sleep-wake schedule.

You should also try to go to bed at the same time every night (hopefully that’s at least seven hours before your wake-up time).

If you have a hard time falling or staying asleep, try these strategies.

See your doctor

Many health problems can disturb sleep, such as chronic pain, restless legs syndrome, sleep apnea, heartburn, incontinence, medication side effects, stress, anxiety, and more. Talk to your doctor to identify and treat underlying conditions or change a troublesome medication.

If your doctor suspects that you have chronic insomnia, it might be time to try cognitive behavioral therapy for insomnia (see “What is CBT-i?”) or work with a sleep specialist. But try not to put it off. Your health — especially your heart health — and longevity are at stake.

What is CBT-i?

Cognitive behavioral therapy for insomnia (CBT-i) is a safe and effective non-drug approach to treat chronic insomnia. To find a therapist, check the Society for Behavioral Sleep Medicine website at https://www.behavioralsleep.org. Click “Providers.”

Another option is an app called CBT-i Coach, developed by the Department of Veterans Affairs. While it was designed for people suffering from insomnia and post‑traumatic stress disorder, anyone can download it for free.

(Heidi Godman is the executive editor of the Harvard Health Letter.)

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