As a child, it always felt like adults had all the fun. Grown-ups were allowed to do anything; drive cars, watch TV for as long as they want, and even stay up late. The hours following nine or ten o’clock at night felt like a forbidden, almost magical period. Of course, for those of us who’ve grown up, we know that staying up late is just a time to catch up on our favorite shows or waste a few hours on Reddit.
Whether you’re a natural night owl or an avid early riser, a new study conducted at Notre Dame University has some advice, and it’s sure to infuriate all of our inner children. Stick to a strict bedtime each night, it’s good for your heart.
Researchers found a correlation between one’s bedtime regularity and subsequent resting heart rate (RHR). More specifically, they discovered that individuals who went to sleep just 30 minutes later than their usual bedtime experienced a significant increase in their overnight heart rate that persisted into the following day.
“We already know an increase in resting heart rate means an increased risk to cardiovascular health,” says lead study author Nitesh Chawla, the Frank M. Freimann Professor of Computer Science and Engineering at Notre Dame, director of the Center for Network and Data Science, in a press release. “Through our study, we found that even if you get seven hours of sleep a night, if you’re not going to bed at the same time each night, not only does your resting heart rate increase while you sleep, it carries over into the next day.”
Everyone knows that sleep is essential, but it was never considered important before whether you went to sleep before midnight or at four in the morning, as long as you slept for around seven or eight hours. These findings, however, appear to be a pretty significant game-changer regarding how we should approach our sleep schedules.
While a fast heart rate doesn’t sound all that bad at first, a consistently elevated resting heart rate can increase one’s risk of heart attack or stroke.
When it comes to investigating inconsistent sleep schedules, who better to analyze than college students? The research team utilized data collected from 557 university students over a span of four years. During that time 255,736 sleep sessions were recorded. Each of those sessions documented the subject’s bedtime, time spent sleeping, and resting heart rate. Participants’ heart rates were also tracked during the day.
Noticeable increases in resting heart rate were observed whenever a student would go to bed later than their usual bedtime. The later a participant would stay up, the faster their heart rate would become as they slept. This increased resting heart rate would often last well into the next day.Even students who went to bed earlier than usual saw their heart rate increase, but there were some caveats. Going to bed around a half-hour earlier than usual didn’t seem to have much of an effect on heart rate but when students hit the sack extra early (more than a half-hour before their usual bedtime) their resting heart rate significantly bumped up while asleep before returning to normal by the morning.
Sleep and its nuances is a complex topic. Some nights we fall asleep as soon as our heads hit the pillow, while others are spent staring at the ceiling for hours on end. No one is saying following a strict bedtime is easily accomplished, but it may be a challenge worth meeting.
“For some, it may be a matter of maintaining their regular ‘work week’ bedtime through the weekend,” Chawla concludes. “For shift workers and those who travel frequently, getting to bed at the same time each night is a challenge. Establishing a healthy bedtime routine — as best you can — is obviously step number one. But sticking to it is just as important.”
The full study can be found here, published in Nature.