How Sleep May Mend the Heart

Sleep has emerged in recent years as an essential factor in preserving heart health, with studies linking sleep to better blood pressure, lower cholesterol, and a reduced risk of heart attack and stroke.

Now, new research suggests that sleep may also mend a heart that’s already been injured. The study, published Oct. 30 in Nature, has found that sleep is vital to recovery in mice that have experienced a heart attack.

The new research also found clues—from samples collected as part of a sleep restriction study conducted by Columbia sleep investigators—that suggest sleep may play the same role in people.

We spoke to Marie-Pierre St-Onge, associate professor of nutritional medicine at Columbia University Vagelos College of Physicians and Surgeons, who led the original sleep study and is a co-author of the new Nature study, about the research and why sleep is so important.

What did your original Columbia sleep study show?

Until recently, it was unclear if a lack of sleep causes an increased risk of heart disease or just correlates with cardiovascular disease.

We designed our study to determine if lack of sleep is a causal factor in the development of heart disease. Measuring the health impacts of chronic sleep loss in people is difficult. We asked our participants, all of whom had adequate sleep duration to begin with, to reduce their sleep by 90 minutes each night for six weeks, which was arduous for them.

Our study showed poor sleep—even the mild sleep deficit that two-thirds of Americans experience—causes changes in the body that increase the risk of heart disease.

It’s one of the first to show a causal connection between sustained, mild sleep insufficiency and heart disease risk.

How did that study help show that sleep is needed to heal the heart after a heart attack?

In the new Nature study, our Mount Sinai collaborators found that after a mouse has a heart attack, the brain releases factors that promote sleep. Sleep, in turn, promotes healing of the heart. Mice deprived of sleep after a heart attack experienced an influx of inflammatory cells to the heart, worsened cardiac function, and a higher death rate.

When our collaborators analyzed blood samples from participants in our sleep study, they found similar migratory inflammatory cells when the study participants were sleep-restricted compared to when they obtained adequate sleep.

Our participants were healthy—none had had a heart attack—but the finding demonstrates that what happens in sleep-deprived mice after a heart attack also happens in sleep-deprived people.

Should sleep be prescribed for people recovering from a heart attack?

At the end of the day, what we want to do is help people. It’s important to see if people with cardiovascular disease can improve their heart’s condition by improving their sleep.

But this needs to be tested. Our lab is interested in studying the impact of sleep improvement for better cardiovascular health.

After people have a heart attack, the focus is usually on changing diet, getting more exercise, and losing weight. Based on what we know now, it seems imperative to add sleep to these patient’s lifestyle recommendations.