March 8 (UPI) -- Having an unpredictable sleep pattern can put a person a higher cardiovascular risk, a new study says.
People whose nightly sleep length varied by more than two hours on average were 2.2 times more likely to have a stroke, congestive heart failure and coronary heart disease, according to a study presented this week at the American Heart Association's Epidemiology and Prevention/Lifestyle and Cardiometabolic Health Scientific Sessions.
"Sleep regularity is an understudied area with critical relevance to everyone. Understanding its relationship with cardiovascular disease has important public health implications and may identify novel strategies for cardiovascular disease prevention," Tianyi Huang, an associate epidemiologist at Brigham and Women's Hospital and study lead author, said in a news release
Additionally, the time it took a person to go to sleep also had a negative effect on their heart. If a person's bedtime varied by more than 90 minutes, they had twice the risk of a cardiovascular episode, the study says.
Much of the problem comes from digital devices. People seem to be getting distracted by smartphones, smart tablets and other devices with bright screens before they go to sleep.
"If our results are confirmed, the general public -- particularly those at high risk for cardiovascular disease -- needs to pay more attention to their sleep schedules," Huang said. "People should be encouraged to reduce use of mobile devices or TV viewing before sleep to improve sleep regularity and maximize cardiometabolic benefits."
Many studies have already established that sleeping fewer than six hours a night can lead to heart disease. Other studies have reported that having sleep apnea makes a person three times more likely to have heart failure.
Each year, about 610,000 people die from heart disease, according to the Centers for Disease Control and Prevention.
"I think it's important for doctors to ask their patients about their sleep habits beyond the number of hours of sleep they get at night," Marie-Pierre St-Onge, a researcher at Columbia University, said in a news release. "Questions like, 'How stable is your sleep?' and 'Do you have wide swings in the duration of sleep?' would help to identify areas for improvement."
The researchers say this is the first study to examine the impact of sleep time and irregularity on heart health, and they want to see more work done on the subject.
"People might not have outward signs -- they might not even feel sleepy or yawn, just like people don't feel it if they have high blood pressure or high cholesterol levels. But the risk factor is still there," St-Olge said. "People need to pay more attention and be more aware of the adverse impact poor sleep is having."