The time you choose to go to sleep may help determine your odds of developing heart disease, according to new data published in European Heart Journal – Digital Health. In fact, researchers found, hitting the sack between 10 p.m. and 11 p.m. may be the optimum time when it comes to taking care of your heart.
Researchers point out that although there have been many studies exploring the association between sleep duration and cardiovascular disease, the relationship between sleep timing and heart disease remains uncharted territory.
In this study, authors analyzed the association between “objectively measured, rather than self-reported” sleep among a group of adult participants.
Researchers examined data from 88,026 patients who were originally recruited for the UK Biobank database from 2006 to 2010. Fifty-eight percent of patients were women, and the mean patient age was 61 years old.
A wrist-worn accelerometer collected data on each person's sleep patterns over a seven-day period.
Patients filled out demographic, lifestyle, health, and physical assessment questionnaires.
In an average follow-up period of 5.7 years, 3,172 participants (3.6%) developed cardiovascular disease.
Prevalence was highest in patients with sleep times at midnight or later and lowest in patients who went to bed between 10 to 10:59 p.m.
The study's authors examined the link between sleep onset and cardiovascular events after adjusting for age, sex, sleep duration, the time patients went to sleep and woke up, smoking status, body mass index, diabetes, blood pressure, blood cholesterol and socioeconomic status.
Compared with patients who went to sleep between 10 and 10:59 p.m., there was a 25% higher risk of cardiovascular disease when sleep onset was at midnight or later, a 12% increased risk when it was between 11 to 11:59 p.m., and a 24% elevated risk for patients who fell asleep before 10 p.m.
“Our study indicates that the optimum time to go to sleep is at a specific point in the body’s 24-hour cycle and deviations may be detrimental to health," study author David Plans, BA, MSc, PhD, of the University of Exeter in England, said in a prepared statement. "The riskiest time was after midnight, potentially because it may reduce the likelihood of seeing morning light, which resets the body clock."
While the association with increased cardiovascular risk was greater in women, Plans et al. noted that the reasons were vague.
“It may be that there is a sex difference in how the endocrine system responds to a disruption in circadian rhythm," Plans said. "Alternatively, the older age of study participants could be a confounding factor since women’s cardiovascular risk increases post-menopause – meaning there may be no difference in the strength of the association between women and men."
Sleep patterns, the authors concluded, should now be seen as something to consider when reviewing a patient's potential risk factors related to cardiovascular disease.
"If our findings are confirmed in other studies, sleep timing and basic sleep hygiene could be a low-cost public health target for lowering risk of heart disease," Plans said.
The full study is available here.