When is the optimal time to fall asleep? British researchers have investigated this question in relation to heart health.
Sleep and heart health are closely linked, as numerous studies have proven. Too little or too much sleep can disrupt the body’s biorhythm and thus increase the risk of cardiovascular diseases. But it’s not just how long we sleep that’s important – when we go to sleep also has an influence on our heart.
Going to sleep early or late – which is better for the heart?
A study by the European Society of Cardiology (ESC) provides the answer: people who fall asleep between 10 p.m. and 11 p.m. have a lower risk of developing cardiovascular disease than those who go to bed earlier or later.
“The body has a 24-hour internal clock, a circadian rhythm, that helps regulate the functioning of the body and the psyche,” study author David Plans from the British University of Exeter is quoted as saying in an ESC press release. Although no causality could be firmly established from the study, going to bed too early or too late is more likely to damage the circadian rhythm and thus have negative effects on cardiovascular health.
First long-term study on the optimal time to sleep
Previous studies had focused on the relationship between sleep duration and cardiovascular disease. Now, for the first time, a large sample has been used to examine the connection between the time at which people fall asleep and the risk of cardiovascular disease.
The researchers analyzed data from more than 88,000 people from the British “UK Biobank” register with information from 2006 to 2010. The average age of the test subjects was 61 years. 58 percent were women.
The participants documented their lifestyle in detailed questionnaires. Variables such as gender, age, sleep duration, body mass index and previous illnesses such as diabetes or high blood pressure were also taken into account. They also wore a sleep tracker on their wrist for a certain period of time. The data was then compared with the frequency of occurrence of cardiovascular diseases such as heart attacks, and chronic ischemic heart disease.
Falling asleep after midnight is most problematic
The result of the analysis: After an average of 5.7 years, cardiovascular diseases developed in 3.6 percent of the test subjects. Most occurred in those who went to bed at midnight or later. The fewest cases were recorded in people who regularly went to bed between 10 p.m. and 11 p.m.
Study author Plans explained: “The most dangerous time was after midnight, possibly because this reduces the likelihood of seeing morning light, which resets the internal clock.”
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