While plenty of uncontrollable factors like genetics can influence heart health, about 80% all cardiovascular disease cases are preventable through lifestyle. Steps like quitting smoking, regularly moving your body and loading up on high-fiber foods all can lower your risk of heart disease.
And new research published in the European Heart Journal – Digital Health this week suggests there’s another simple but potentially powerful lifestyle tweak that can help: Going to bed at a certain time.
People who fall asleep between 10 p.m. and 11 p.m. have a lower risk of developing cardiovascular disease than people who fall asleep either before or after that time window.
“The body has a 24-hour internal clock, called circadian rhythm, that helps regulate physical and mental functioning,” study author David Plans, head of research at the British health care technology company Huma, said in a statement.
“While we cannot conclude causation from our study,” Plans added, “the results suggest that early or late bedtimes may be more likely to disrupt the body clock, with adverse consequences for cardiovascular health.”
The power of circadian rhythms
Plans and his team analyzed data from more than 88,000 participants in the UK Biobank, a massive database of health and lifestyle data available for research. Participants answered questions about their daily health habits and wore a device that logged when they fell asleep at night as well as when they woke up in the morning. The average age of the study participants was 61, and roughly 60% were women.
Overall, the researchers found that people who fell asleep at midnight or later had a 25% higher risk of developing cardiovascular disease than those who fell asleep between 10 p.m. and 11 p.m. Those who fell asleep between 11 p.m. and 11:59 p.m. had a 12% higher risk. And those who fell asleep before 10 p.m. had a 24% increased risk.
The researchers did what they could to control for other factors known to increase a person’s risk for heart disease, like smoking, high blood pressure and socioeconomic status. They found the bedtime and heart health link still stood.
While the new study cannot establish cause and effect, the researchers believe their findings may have a lot to do with a person’s natural circadian rhythms ― the internal 24-hour sleep clock closely tied to the light and dark cycle of the sun. When that internal clock is disrupted by early or late bedtimes, it can negatively impact the heart, the researchers believe.
This certainly isn’t the first hypothesis of its kind. Circadian rhythms are known to affect many bodily systems, and previous research has shown that people with atypical bedtimes — particularly the millions of Americans who do shift work — are at greater risk for heart disease. Yes, working off-hours can make it much more challenging for people to exercise or eat nutritious meals. But shift work is also believed to impact people’s underlying biological systems.
“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,” Plans said. (Plans and his co-researchers disclosed that their study was financially supported by Huma, but that the company played no role in data collection or analysis.)
Another argument for prioritizing sleep
While the researchers who conducted the new study cautioned that more work needs to be done to understand the potential connection between bedtimes and heart health, they believe their research reveals powerful clues.
“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.
Of course, people cannot necessarily control their bedtimes, especially those whose jobs require them to work late into the night or very early in the mornings.
But to the extent it’s possible, sleep experts say you should be relatively consistent about when you go to sleep and when you wake up — and aim for a bedtime that means you can get at least seven to eight hours of sleep. Also, avoid large meals and caffeine before bed and try to create a quiet, dark sleep environment.
As more and more research shows, doing what you can to prioritize good sleep isn’t just good for you the next day. It can make a big difference in your overall health in the long run.