Irregular sleep doubles risk for CVD
Brigham and Women’s Hospital physicians have discovered that irregular sleep patterns can significantly hike a person’s risk for heart disease, even if they’re otherwise healthy.
Tianyi Huang, ScD, of the Brigham’s Channing Division of Network Medicine, and colleagues analyzed a cohort of patients from the MESA (Multi-Ethnic Study of Atherosclerosis) study, which recruited white, black, Hispanic and Chinese-American patients to wear an activity tracker on their wrist for a week. The tracker recorded sleep data, including sleep duration, bedtime and wake time.
Huang said sleep is something physicians typically fail to focus when discussing treatment options and lifestyle changes with their patients.
“When we talk about interventions to prevent heart attacks and stroke, we focus on diet and exercise,” he said in a release. “Even when we talk about sleep, we tend to focus on duration—how many hours a person sleeps each night—but not on sleep irregularity and the impact of going to bed at different times or sleeping different amounts from night to night. Our study indicates that healthy sleep isn’t just about quantity but also about variability, and that this can have an important effect on heart health.”
Over nearly 5 years of follow-up, 111 patients in MESA experienced CV events, including MI and stroke. Huang et al. divided the 1,992 original participants into four groups based on their sleep patterns and bedtimes; people who had the “most irregular” sleep patterns were those whose sleep duration differed by two hours or more each night, and people with the “most regular” patterns had less than an hour difference in sleep duration each night. The most inconsistent bedtimes were considered those that differed by 90 minutes or more each night, with the most consistent bedtimes being those that differed by less than 30 minutes each night.
Huang and colleagues found a twofold increase in CVD risk among people with the most irregular sleep patterns, meaning that, for every 1,000 people with poor sleep patterns, 20 would likely develop a cardiovascular event over the course of one year. On the other hand, for every 1,000 people with regular sleep patterns, just 8 were estimated to suffer a CV event over the course of a year.
Huang said larger studies need to confirm his team’s findings, but if they do, he’d like to assess whether certain interventions, like sleeping longer or setting a strict bedtime, could reduce CVD risk.
“Sleep regularity is a modifiable behavior,” he said. “In the future, we’d like to explore whether changing one’s sleep patterns by going to bed consistently each night may reduce a person’s risk of future cardiovascular events.”
After graduating from Indiana University-Bloomington with a bachelor’s in journalism, Anicka joined TriMed’s Chicago team in 2017 covering cardiology. Close to her heart is long-form journalism, Pilot G-2 pens, dark chocolate and her dog Harper Lee.