Can going to bed at 10 p.m. reduce heart disease risk?
A new study published this month in the European Heart Journal – Digital Health found that when it came to heart health, going to sleep between 10 and 11 p.m. was ideal.
People who fell asleep after midnight had a 25% increased risk of cardiovascular disease. Those who fell asleep before 10 p.m. had a 24% increase in cardiovascular disease. And those people who fell asleep between 11 p.m. and midnight had a 12% increase in heart disease.
The study looked at more than 88,000 people from 2006 to 2010 and then followed up about five years later.
This study, though, can be misinterpreted, said Dr. Stanley Wang, medical director at the sleep disorder center at the Heart Hospital of Austin.
"There's a lot of temptations to spin it the wrong way," he said. "It's not that by going to sleep between 10 and 11, you will automatically have a lower risk of heart disease."
He likens it to saying that all wealthy people go to bed between 10 and 11 p.m., and therefore by going to sleep at that time, you will automatically become wealthy.
Instead, it's about the healthful patterns that people who go to sleep at that hour exhibit. The people who go to sleep earlier might be having trouble staying awake because of poor quality of sleep the night before. The people who go to sleep afterward might be having trouble falling asleep or getting enough sleep.
Wang said multiple studies have shown a link between quality of sleep and heart disease. We know that having sleep apnea doubles the risk of congestive heart failure and atrial fibrillation specifically and triples the risk of heart disease in general. People with restless leg syndrome and insomnia have higher blood pressure, he said.
We've talked about diet as having a major impact on heart disease, but now we're talking about sleep having a major impact, Wang said.
What's important is consistency: going to sleep at the same time every day, getting up at the same time every day, eating meals at the same time every day. Those behaviors set your internal circadian rhythm, the body clock that naturally tells you when to be awake and when to be asleep.
Getting out of that circadian rhythm is stressful for the body, Wang said. That's why when we have things such as changes in daylight saving time, there's a surge in heart attacks and car wrecks, Wang said. It's stressful for our bodies.
People who aren't getting enough consistent sleep might make other choices that affect their health, such as using alcohol to fall asleep, or using caffeine and sugar to stay awake, Wang said.
Tips for better sleep
Set a consistent sleep schedule. Go to bed at the same time and get up at the same time every day.
Wake up with light. Your body needs light in the morning and throughout the day to set its body clock to be awake during those hours. Choose an office with a lot of light rather than one that is dimly lighted. Blackout shades make it hard to wake up in the morning.
Go to sleep in dark. Darken rooms at night. Avoid using devices with a lot of light exposure such as cellphones, TVs, computers and tablets at night. If you must, use the night setting, though there has not been a full scientific study indicating that such settings are better than the regular setting, Wang said. It's just a theory.
Get ready for bed. Avoid excess alcohol, caffeine and high-intensity exercise two to three hours before bedtime.
Avoid a multiuse bedroom. If you train your brain that the bedroom is also your office or your entertainment center, it's hard to wind down to sleep there. Keep the TVs, phones and computers out of the bedroom.
Limit the distractions in the bedroom. That can mean pets, too.
Talk to a doctor if you are waking up frequently to use the bathroom or because of hormonal shifts (night sweats), or if someone tells you that you snore, stop breathing or wake up gasping during the night.