(CNN) If you want to keep your heart healthy, add a good night's rest to your to-do list, a new study says.
Heart disease is the No. 1 killer in the country, according to the US Centers for Disease Control and Prevention. Someone in the US dies from cardiovascular disease every 34 seconds.
In June, the American Heart Association added sleep duration to its cardiovascular health checklist, now called "Life's Essential 8." These science-based guidelines were created to help all Americans improve their heart health.
The eight items: Quit tobacco, eat better, get active, manage weight, manage blood pressure, control cholesterol, reduce blood sugar and get healthy sleep.
Some of the research behind the change was published Wednesday in the journal of the American Heart Association.
The research, from scientists at Columbia University's Mailman School of Public Health, shows that the cardiovascular health guidelines are more effective at predicting a person's risk of heart disease if they include sleep.
The researchers looked at sleep records from 2,000 middle-age or older adults in an ongoing US study of cardiovascular disease and cardiovascular disease risk factors called the Multi-Ethnic Study of Atherosclerosis, or MESA.
The participants took part in detailed sleep research. They filled out sleep surveys, wore a device that measured their sleep for seven days and did an overnight study in which scientists could observe the way they slept.
Poor sleep habits "are ubiquitous" among Americans, the study says, including among the study participants. About 63% of them were found to sleep less than seven hours a night, and 30% slept less than six hours. Optimum sleep duration for an adult is between seven and nine hours a night, according to the CDC.
People who slept less than seven hours a night had a higher chance of "low sleep efficiency," irregular sleep patterns, excessive daytime sleepiness and sleep apnea. Specifically, nearly half of the people in the study had moderate to severe sleep apnea. More than a third reported insomnia symptoms, and 14% reported excessive daytime sleepiness.
Those who slept less than seven hours had a higher prevalence of heart disease risk factors like obesity, type 2 diabetes and high blood pressure. Other research has also shown connections between short sleep and chronic diseases that could also hurt heart health.
"Poor sleep is also linked to other poor health behaviors," said study author Nour Makarem, an assistant professor of epidemiology at the Mailman School of Public Health. Those poor health behaviors also contribute to poor heart health.
There's increasing evidence that people who don't sleep enough often have a poor diet, Makarem said. That may in part be because sleep is a restorative process that, among other things, produces and regulates hormones that can make you feel full or hungry. When those hormones get out of whack, you may end up eating more and seeking out calorie-rich foods that give you quick energy.
Poor sleep is also linked to a lower engagement in physical activity, Makarem said.
"Both a poor diet and lack of exercise, of course, are also an important risk factor for heart disease," she said. "So sleep is related to a lot of cardiovascular disease risk factors, even including psychological risk factors."
Poor sleep can raise stress levels and risks of depression, both of which also affect heart health.
"In a nutshell, sleep is related to clinical or psychologic and lifestyle-related risk factors for heart disease. So it is not a surprise that poor sleep would increase future heart disease risk," Makarem added.
Sharon Cobb, the director of prelicensure nursing programs and an associate professor at the Mervyn M. Dymally School of Nursing at Charles R. Drew University of Medicine and Science in Los Angeles, said it's important that health-care providers take sleep into consideration when evaluating someone's health overall.
She hopes future studies will provide additional evidence of a connection between good health and good sleep and prompt more providers to ask questions.
"They take your blood pressure, they ask you about how well you eat and how much you exercise, but not a lot ask 'how well are you sleeping at night?' " said Cobb, who was not involved in the new research. "Getting good sleep is essential to promote good health."