Researchers are still trying to determine the exact relationship between sleep and healthy hearts, although the connection is well-established. New research suggests that there may be an optimal time to fall asleep within the 24-hour clock.
The reasons why you don't get the right amount of sleep or the right time are often beyond our control. Anyone who is having trouble sleeping should seek medical advice. They should also focus on what works for them, rather than dictating their bedtime.
For the rest of us, it might be useful to know that falling asleep between 10-11 p.m. seems to be the ideal time for a healthy cardiovascular system.
David Plans, University of Exeter psychologist, says that the body has a 24-hour internal rhythm called the circadian rhythm. This helps regulate mental and physical functioning.
Although we can't prove causation, our results indicate that bedtimes of early or late may disrupt the body's clock with negative consequences for cardiovascular health.
A research team from Huma Therapeutics AI, digital healthcare company, was able to analyze wrist-worn accelerometer data and compare it with later health outcomes.
The dataset contained 3,172 cases of heart disease during nearly six years of monitoring participants.
According to the team, falling asleep before midnight or before 10 p.m. was associated with a 25% increase in cardiovascular disease risk. This is in contrast to falling asleep between 10-11 p.m. The risk of developing cardiovascular disease dropped to 12 per cent for those who fell asleep between 11-12pm.
Plans states that the riskiest time to see morning light was after midnight.
When you consider age, gender and sleep duration, whether you are an early bird or a night owl, smoking status as well as weight, socioeconomic status, blood pressure, cholesterol, and other factors, this trend was consistent. Researchers are still not sure why women were more affected.
Plans suggests that "it may be that there's a sex differential in how the circadian rhythm is affected by disruptions in endocrine system response," Plans says.
"Alternatively, the older age study participants could be a confounding fact since women's cardiovascular risks increase post-menopause. This may mean that there may not be any difference in strength of the association between men and women."
This study cannot determine if the sleep time itself is a factor in heart disease. It may be other habits, such as drinking too much or stress that keeps people awake, that are contributing to the problem.
The study was also limited in age, socioeconomics, and ethnicity. It looked at whites who were more wealthy between the ages of 43 and 79. This may not be true for all demographics.
However, biometric data can eliminate recall biases that might be present in studies that rely on survey data.
These results are consistent with prior research that showed an increased risk of developing cardiovascular problems in people who slept late. They also align with what we know about the physiology and function of our bodies clock, which requires a periodic reset.
Plans explained to The Guardian that misalignment in behaviors and the circadian rhythm can lead to inflammation and impair glucose regulation. Both of these factors can increase cardiovascular disease risk.
This trend is worth further research, as diseases of the heart, blood vessels, and other conditions are among the most common causes of death in the world, even the United States.
Plans concluded that "if our findings are confirmed by other studies, sleep timings and basic sleep hygiene could become a low-cost target public health goal for lowering the risk of heart disease."
This research was published by the European Heart Journal – Digital Health.