Heading to bed at one specific hour could significantly reduce your risk of heart disease, as suggested by a new study. It finds participants who went to bed between 10pm and 10:59pm were at a lower risk of developing cardiovascular disease than those who put their head on the pillow between 9pm and 9:59pm, or between 11pm and 11:59pm. "While we cannot conclude causation from our study, the results suggest that early or late bedtimes may be more likely to disrupt the body clock, with adverse consequences for cardiovascular health," study co-author David Plans of the University of Exeter says in a statement, per NBC News.
Plans and colleagues pulled the bedtimes of 88,926 participants of the UK Biobank, aged 43 to 79, who wore motion-monitoring devices for a week. They then followed up with these participants after an average of 5.7 years, at which point 3,172 (3.6%) had experienced a cardiovascular event. The data showed those who went to sleep from 11pm to 11:59pm had a 12% higher risk of developing cardiovascular disease than those who went to bed between 10pm and 10:59pm, while those who went to sleep after midnight had a 25% higher risk. A later bedtime suggests less overall sleep, which has been linked to a higher prevalence of obesity, Type 2 diabetes and high blood pressure. But the results were adjusted for sleep duration as well as age and other cardiac risk factors.
"The riskiest time was after midnight, potentially because it may reduce the likelihood of seeing morning light, which resets the body clock," Plans says, per the BBC. If the body clock is not properly reset over a long period, "that misalignment of behaviors and the circadian clock increases inflammation and can impair glucose regulation, both of which can increase risk of cardiovascular disease," he adds, per the Guardian. A bedtime prior to 10pm was hardly better, showing a 24% higher risk, according to the study published Monday in the European Heart Journal - Digital Health. The findings were stronger in women than in men, with Plans noting there may be "a sex difference in how the endocrine system responds to a disruption in circadian rhythm." (Read more heart health stories.)