A restful night’s sleep impacts your mood, energy, and productivity — it’s also associated with a healthy heart. Here’s why.
You’re likely familiar with the guidance on maintaining a healthy heart: eat minimally processed foods; exercise; maintain healthy blood sugar levels, keep your cholesterol in check; don’t smoke.
But did you know that logging enough zzz’s can also affect your heart health?
In July 2022, the American Heart Association added sleep to its cardiovascular health checklist — a list of eight factors a person can modify to maintain heart health. These include diet, exercise, tobacco use, weight, cholesterol, blood sugar levels, blood pressure, and, now — sleep.
The decision is based on research demonstrating the link between sleep and cardiovascular health. Brooke Aggarwal, an assistant professor of medical sciences in the Division of Cardiology within Columbia University’s Department of Medicine, conducted one such study that showed sleep deprivation (defined as fewer than five hours a night) among women is associated with a greater risk of hypertension, or high blood pressure, which is a known heart risk.
Aggarwal says she’s happy to see sleep added to the heart health checklist in part because it gives credibility to sleep researchers and others who care about sleep’s effects on overall health. She said it’s taken about a decade for it to get the attention it deserves. Going forward, it will change how practitioners address patient health.
“Cardiologists all across the country should be asking their patients as part of routine clinical encounters about sleep,” she says. “That will be an official part of a patient’s medical records.”
So, how exactly does sleep impact heart health? How do researchers define how much sleep is enough? And why does sleep quality matter as much as sleep duration? We caught up with Aggarwal to understand these and other questions about the connection between heart health and a good night’s rest.
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How does sleep impact cardiovascular health?
BA: It’s hard to quantify the benefit of good sleep in preventing heart disease, says Aggarwal. However, sleep can increase risk factors that are measurable.
Reduced or poor-quality sleep can increase blood pressure, for instance, which is a known risk factor for heart disease. It can also increase inflammation — or your immune system’s response to illness and disease — in the body. One study showed that women who experienced poor sleep quality had observable inflammation in the lining of their cells.
Overall, sleep improves heart health because it’s restorative, reduces inflammation, and regulates blood pressure.
Poor sleep can affect heart health in indirect ways, too. For instance, it can influence levels of physical activity and is associated with increased sugar intake. Both of these things can impact heart health over time.
“People who [don’t] sleep well are more attracted to unhealthy foods,” says Aggarwal. “An unhealthy diet can lead to poor sleep, and it can go the other way, too.”
Read more: How Food and Alcohol Affect Sleep
How do we define quality sleep?
BA: Doctors can use a subjective measurement known as the Pittsburgh Sleep Quality Index to assess how well a person is sleeping. Practitioners score their patients based on a series of questions the patients answer about their sleep, including what time they go to bed, what time they rise in the morning, and how many hours of actual sleep they get.
Practitioners can also use a hectograph watch, which measures a person’s movements and can report on how long a person spends asleep.
At home, people can get an idea of their sleep quality by tracking it with a smart watch.
Aggarwal caveats that these methods aren’t perfect, but they can provide insight into how much and how well a person is getting much-needed zzz’s.
When we talk about sleep, are we talking about duration or quality? Or both?
BA: For now, the AHA refers only to sleep duration in its updated checklist — it notes that seven to nine hours daily is ideal for adults. However, studies suggest that sleep quality is just as important. Research has shown that poor sleep quality is associated with greater food intake and a lower-quality diet, both of which can increase the risk of heart disease.
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What about consistency of sleep?
BA: Sleep consistency — or going to bed and waking up at the same time every day — is also not mentioned in the AHA’s checklist.
However, Aggarwal says establishing a consistent wake and bed time can impact health. During one sleep-related study, Aggarwal noted she unexpectedly found that the study’s control group, which had a prescribed wake and sleep time, lost weight just by keeping these routines consistent.
More research is needed to fully understand the effects of a consistent sleep routine on a person’s health, but if you want to improve your own, Aggarwal suggests keeping your day-to-day variability in wake and bed time within 60 minutes.
Why is it important to understand risk factors for heart disease?
BA: Cardiovascular disease is the number one killer of men and women, says Aggarwal. In the U.S., one person dies every 34 seconds from cardiovascular disease.
The good news: You can mitigate your risk. Research suggests that people can prevent more than 80 percent of cardiovascular events — this includes everything from heart attacks to coronary artery disease — by making healthy lifestyle choices and managing known risks. This includes understanding your family history of heart disease and reviewing the AHA’s cardiovascular health checklist.
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