There’s a reason they call it “beauty sleep.” Your energy levels, immune system and mental health, just to name a few important bodily functions, rely on ample shut-eye. The problem? For many of us, logging time in bed feels like a luxury.
The National Sleep Foundation recommends healthy adults get between seven and nine hours of sleep each night, but that’s not always easy or even possible — especially if you have a busy daytime schedule and an insatiable need to unwind with Netflix and TikTok until midnight. Social and cultural factors, like being a single parent or working extra shifts, can make it that much harder to keep up with doctor’s orders.
If you’re sleep-deprived during the week, logging a few extra hours on the weekend might seem like the perfect solution. But before you mute your alarm this Saturday, understand that not all sleep is created equal. Yes, plenty of science shows sleep deprivation can take a major toll on your daily functioning and well-being — but too much sleep, especially at the wrong time, can mess with your overall sleep routine and actually worsen many of the problems that come from a bad night’s sleep.
Your circadian rhythm — the internal clock that determines when you fall asleep and wake up — relies on consistency. “When you’re consistent, your body knows what time you’ll go to bed, so it will release melatonin a few hours before your intended bedtime to make you sleepy,” says Dr. Stephanie Stahl, a sleep medicine physician at Indiana University Health in Indianapolis.
When your sleep schedule is all over the place, your body won’t know when to produce this sleep-inducing hormone; as a result, your sleep (and overall health) could suffer. Stahl says adults should aim to get seven hours of sleep each weeknight, around 35 hours of sleep per work week.
Say you miss a few hours during the week and sleep in on Saturday morning. Although you’ve made up some of those lost hours, sleeping past your normal time could do your body a big disservice by affecting your sleep schedule for the following week.
This can damage your health short and long term. A 2019 study found that people who caught up from sleep deprivation on the weekend, shifting from five hours to as many hours as they wanted, developed worse insulin sensitivity, suggesting a link between weekend recovery sleep and metabolic diseases like diabetes, heart disease and stroke. (You guessed it: Melatonin plays a role in your metabolism too).
Another study from 2017 found that college students with erratic sleep schedules had lower GPAs than their well-rested peers, even if they got the same overall amount of sleep during the week. This suggests messing with your circadian rhythm can hamper your cognitive abilities. On top of these risks, some research finds a link between erratic sleep schedules and low mood and depression.
You can actually address sleep debt without hurting your health by taking a nap. Research suggests sneaking in a bit of extra shut-eye during the day can help people learn more effectively and perform better on cognitive tasks.
But napping isn’t without risk, especially if you do it the wrong way. Sleeping too long or snoozing late in the day can also make it difficult to doze off at night, says Stahl — or it can cause you to wake up more in the middle of the night.
Dr. Rafael Pelayo, a sleep specialist at Stanford Health Care in Redwood City, California, suggests waking up at your normal time, then taking a short nap during the day whenever you notice yourself feeling tired. For most people, that’s right after lunch, when the circadian rhythm dips; humans evolved to take a rest period around this time. “Instead of messing up your body’s wakeup time predictions, you can take advantage of the physiological dip in alertness and body temperature and take a nap then,” he says.
Stahl suggests limiting your nap to 30 minutes in the first half of the day to avoid causing issues with your circadian rhythm. “I usually tell people to be done napping by 3 p.m., or seven hours before bedtime, because that’s less likely to impact your ability to sleep at night,” she says.
Of course, the best way to address sleep deprivation is head on. Stahl recommends avoiding sleep debt in the first place by prioritizing resting at least seven hours at night. That may mean rethinking what self-care really means and making some tough decisions about your routines.
Either way, with more consistency going forward, your circadian rhythm — and all the important biological functions it helps regulate — will thank you.