LONDON (Dispatches) -- A new study reports that going to sleep between 10:00 and 11:00 pm is linked with a lower risk of developing heart disease compared to earlier or later bedtimes.
The study author Dr. David Plans of the University of Exeter, UK says that the body has a 24-hour internal clock, called circadian rhythm which helps regulate physical and mental functioning and that although they cannot conclude causation from the study , the results suggest that early or late bedtimes may be more likely to disrupt the body clock, with adverse consequences for cardiovascular health.
For the study, 88,026 individuals in the UK Biobank recruited between 2006 and 2010. The average age was 61 years (range 43 to 79 years) and 58% were women. Data on sleep onset and waking up time were collected over seven days using a wrist-worn accelerometer. Participants completed demographic, lifestyle, health and physical assessments and questionnaires. They were then followed up for a new diagnosis of cardiovascular disease, which was defined as a heart attack, heart failure, chronic ischaemic heart disease, stroke, and transient ischaemic attack.
Compared to sleep onset from 10:00 to 10:59 pm, there was a 25% higher risk of cardiovascular disease with a sleep onset at midnight or later, a 12% greater risk for 11:00 to 11:59 pm, and a 24% raised risk for falling asleep before 10:00 pm. In a further analysis by sex, the association with increased cardiovascular risk was stronger in women, with only sleep onset before 10:00 pm remaining significant for men.