People who consistently go to bed very early or very late may face a higher risk of heart attack, according to a study published in the journal Sleep Health.
Researchers tracked 4,578 adults over the age of 40 for an average of 10.6 years. Participants were grouped by chronotype into early risers, an intermediate type, and night owls. The scientists recorded heart attack cases during the study period and accounted for age, lifestyle, cardiovascular risk factors, and objective measures of sleep.
Risk levels by chronotype
Compared with people of intermediate chronotype, the risk of heart attack was 50 percent higher among early risers and 40 percent higher among night owls, the researchers found.
The link was especially strong among participants with obstructive sleep apnea. In that group, the likelihood of a heart attack rose by about 80 percent for both early risers and those who preferred going to bed late and waking up late.
Circadian rhythm and heart health
The study's authors said that not only lack of sleep but also features of a person's circadian rhythm may play an important role in heart health. They said that accounting for chronotype in the future could help more accurately assess cardiovascular disease risk and allow for timely prevention.
Scientists have previously found that smoking speeds up the buildup of plaque in the arteries and raises the risk of heart attack and stroke.
