For more than a decade, the American Heart Association (AHA) urged people to follow “Life’s Simple 7”— a checklist for cardiovascular health that includes maintaining a nutritious diet, avoiding smoking, and getting adequate physical activity. Good adherence to each domain yields a high score, which health experts have long used to determine a person’s risk for heart problems. But in June, the group announced that the program was expanding to “Life’s Essential 8” to make room for another, less-recognized pillar of cardiovascular health: good sleep.
New research suggests that sleep deserves its elevated status. In a study published in the Journal of the American Heart Association on Oct. 19, researchers tracked cardiovascular events—like cardiac arrest and strokes—among 2,000 middle-aged and older people for an average of about four years. The goal was to compare how well AHA’s Simple 7 predicted cardiovascular events, versus when sleep was included. Without sleep, researchers found, a low Simple 7 score was not significantly associated with cardiovascular disease (although past research had linked it to cardiovascular risk). When sleep was weighed in, however, they found it predicted future cardiovascular disease more accurately. What’s more, people who scored the highest on the Essential 8 scale had nearly half the risk of cardiovascular disease events than people who scored the lowest. How long and how well someone slept were both similarly influential for cardiovascular health.
Sleep’s important role came as no surprise, says Nour Makarem, lead author of the study and assistant professor of epidemiology at Columbia University’s Mailman School of Public Health. Past research has linked poor sleep to less-healthy habits, including less nutritious diets, lower physical activity, and greater psychological risk factors for heart disease, including stress. Sleep is also tied to other threats to cardiovascular health, including diabetes, high blood pressure, and obesity. Other research has suggested that sleep affects the mechanisms underlying these conditions, says Makarem, including the hormones that control hunger, the body’s response to insulin, and the systems that govern metabolism.
Read More: Why Not Everyone Needs 8 Hours of Sleep
“Over the past few years, there’s been so much accumulating evidence showing that different aspects of sleep are related to future risk of heart disease, but also studies elucidating what the underlying physiologic mechanisms are,” says Makarem. “It’s become more and more clear in the scientific literature that poor sleep is an important risk factor for heart disease.”
Despite the growing recognition that sleep is important, most adults aren’t getting enough of it. In 2020, about 33% of U.S. adults were getting less than seven hours sleep, which the U.S. Centers for Disease Control and Prevention recommends for adults 18 to 60. People ages 25 to 44 were especially likely to not be getting enough sleep, as were Native Hawaiian and Pacific Islanders and Black adults. Researchers have pointed out that inequality can make it harder for some people to get enough sleep. For instance, Black Americans have been found to have less restful sleep, which has been linked in part to stress.
Another problem, says Makarem, is that getting a good night’s sleep isn’t always seen as a priority. “Sleep seems to be the first thing that people squeeze out of their schedules when they’re busy, either socializing or working,” says Makarem. “The first step is to make time for sleep.” Makarem also suggests building up good sleep habits, including keeping to a regular sleep schedule; taking the time to relax before bed without a screen from a TV or phone, and keeping your bedroom quiet and dark.
Makarem notes that more research is necessary beyond her study, including research that follows people over a longer period and clinical trials that can test whether screening for sleep problems and changing sleep habits can improve cardiovascular outcomes. However, she stresses that the weight of evidence suggests that sleep is important for heart health. “We spend a third of our life sleeping,” says Makarem. “It’s so important to preserving so many aspects of our health and functioning.”