Your Bedtime Could Be Affecting Your Heart Health

There are so many factors that go into your overall heart health, including your diet and level of exercise. But new research has found your bedtime could be just as important.

The November study, which was published in the European Heart Journal—Digital Health, found that going to bed between 10 and 11 p.m. is linked with a lower risk of developing heart disease compared to earlier or later bedtimes.

For the study, the researchers analyzed data from 88,026 people from the U.K. Biobank that were recruited between 2006 and 2010. The participants ranged in age from 43 to 79. The researchers looked at data on when people fell asleep and woke up that was collected over seven days using a device that was worn on their wrist.

The study participants answered questionnaires about their demographic, lifestyle, health, and physical health, and were followed up over an average of about five years years to see if any were newly diagnosed with heart disease. Researchers specifically looked at heart attack, heart failure, heart disease, stroke, and transient ischaemic attack—a stroke-like attack.

During the follow-up period, 3,172 of the study participants (or 3.6%) developed heart disease. The researchers found that the rate of heart disease was highest in people who went to bed at midnight or later and lowest in the 10 to 10:59 p.m. group.

After adjusting for a slew of factors like age, sex, sleep duration, and more, the researchers found that there was a 25% higher risk of heart disease in people who went to bed at midnight or later. People who tended to conk out between 11 and 11:59 p.m. had a 12% greater risk, and those who fell asleep before 10 p.m. had a 24% higher risk.

Link Between Sleep and Heart Health

You need at least seven hours of sleep a night. But according to the Centers for Disease Control and Prevention (CDC), more than one in three American adults say they don't get this much.

Consistently not getting enough sleep can lead to a slew of health problems. Adults who sleep less than seven hours a night are more likely to report having the following health issues:

• Heart attack
• Heart disease
• Stroke
• High blood pressure
• Type 2 diabetes
• Obesity

The American Heart Association also says that people who sleep less than six hours a night are at a higher risk for high blood pressure. As a result, the organization recommends that people try to get enough sleep, along with other heart-healthy habits.

Why Bedtime May Impact Heart Disease Risk

The researchers didn’t study exactly why bedtime might impact heart disease risk—just that there was a link between a certain bedtime and a lowered risk of heart issues.

“The body has a 24-hour internal clock, called circadian rhythm, that helps regulate physical and mental functioning,” study co-author David Plans, PhD, senior lecturer in organizational neuroscience at the University of Exeter, said in a statement. “While we cannot conclude causation from our study, the results suggest that early or late bedtimes may be more likely to disrupt the body clock, with adverse consequences for cardiovascular health.”

As for why going to bed after midnight was the riskiest for heart health, Plans said that “it may reduce the likelihood of seeing morning light, which resets the body clock.”

Christopher Winter, MD, neurologist and sleep specialist and author of the book, "The Sleep Solution: Why Your Sleep Is Broken and How to Fix It," told Verywell that the findings are “very interesting” but said he still thinks sleep duration is more important.

Jennifer Wong, MD, cardiologist and medical director of non-invasive cardiology at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in California, agrees.

"That window may impact how much total sleep a person ends up getting per day,” she told Verywell. “But the researchers did try to adjust for sleep duration and irregularity—it does raise some interesting questions.”

If you go to bed a little earlier or later, Winter said you shouldn’t panic.

“I think that if an individual consistently goes to bed at midnight and awakens at 8 to 9 a.m.—I'm not sure why that schedule would create more risk,” he said. “If it does, it would probably relate to circadian rhythms and how well our schedule synchronizes with our innate rhythm.”

But Winter said there is likely a “lifestyle bias” at play.

“If you go to bed every night between 10 to 11 p.m., you probably have a pretty predictable and consistent schedule—things necessary to go to the gym, work out, etc.,” he said. 

As a whole, Winter stressed that sleep is crucial for your health.

“Sleep plays a huge role in overall health—I’m not sure there are many factors that are bigger,” he said. “Do not shortchange your sleep, even if you feel okay doing so. It is a major factor in your short- and long-term health.”