If you’ve been burning the midnight oil, you’re likely looking forward to the weekend (or a much-deserved vacation) to “catch up” on sleep. But can you really make up for lost hours of shuteye by sleeping in on the weekend?

The short answer, experts say, is no. When you lose hours of sleep, you accumulate “sleep debt.” “Sleep debt is a way of taking out a loan… against your health,” says Mark Burhenne, D.D.S., a member of the American Academy of Sleep Medicine (AASM), and author of The 8-Hour Sleep Paradox. Plus, there’s compound interest — and eventually, it adds up so much that you can’t pay it off. 

The key to avoiding the adverse effects of sleep debt: prevention. Here, learn more about sleep debt, how it affects your health, and how you can avoid it in the future.

How Does Sleep Debt Work? 

Sleep debt is a matter of simple math. If the recommendation for healthy adults is seven to nine hours of sleep per night, but you only get four to six, that creates a sleep debt of one to three hours per night, explains Raj Dasgupta, MD, FAASM, a pulmonary and sleep medicine specialist in California

Just like financial debt, sleep debt also adds up: “If I do the same thing the next night and the night after that, that adds up to a lot of hours I need to catch up on,” Dasgupta notes.

Sleep debt also depends on your individual “optimal” sleep duration, which varies not only person by person, but also for yourself depending on factors such as workload, stress, physical activity, or seasonality, explains Raphael Vallat, PhD, senior machine learning data scientist at Oura.

How Does Oura Assess Sleep Debt?  

In the Oura App, the Sleep Balance Contributor is one the components of your Readiness Score, and can be used to assess your sleep debt. This contributor answers the question: Have you been getting enough sleep in the last 2 weeks?

Oura will nudge you to “pay attention” to your sleep balance if you’re at risk of sleep debt — i.e., you’re sleeping less than you usually sleep or less than the recommended average for your age. Oura uses these four metrics to determine your Sleep Balance contributor:

  • Your personal long-term mean (how much sleep you usually get)
  • Your long-term standard deviation (how much does your Total Sleep time vary)
  • Your average sleep duration over the last 14 days 
  • How much sleep a person your age needs

Regarding this last point, Oura takes into account the fact that more sleep is recommended the younger you are, according to the American Academy of Sleep Medicine, so the minimum recommended amount of sleep gradually (and linearly) decreases as you age.

What Happens When You Have Sleep Debt? 

As the hours of lost sleep multiply, so do the impacts on your health and well-being. Studies show that chronic short sleep duration can result in daytime sleepiness and tank your performance at work. Plus, you might be grouchier: In a study from 2020, people who had five days of sleep debt saw pleasant pictures in a more negative light. 

Short nightly sleep can upset the balance of hormones that control your appetite, making you hungrier. And it can even make you sick: When you sleep 6 or fewer hours per night, your immune system is weakened, so you’re more likely to catch a cold than someone who’s well rested. 

The long-term consequences are even worse: Without proper sleep quantity, your risk of cardiovascular disease and events like stroke and heart attack increase. Risks of diabetes and obesity also rise, as does the risk of early death.  

READ MORE: How Sleep Affects Your Immune System

Why You Can’t “Catch Up” On Sleep

What about sleeping in on the weekend? Unfortunately, getting more sleep on weekends to make up for sleep debt during the week is not a cure-all. Why? Above all, it’s a numbers game. If you accumulate a nightly sleep debt of one to three hours during the week, your sleep debt will add up to five to 15 hours by the weekend. If you “catch up” on four hours over the weekend, you still aren’t making up that 5- to 15-hour debt.

Catching up on more than that is unlikely, Dasgupta says: In studies where people extend their sleep time, people only add an hour or two of extra sleep. 

Weekend sleep-ins can also make the rest of your week’s sleep schedule worse. When scientists studied the ultimate experts on sleeping in — teenagers — they found that those who slept late on Saturday and Sunday didn’t return to a normal sleep schedule for three or four days, resulting in higher levels of stress and more absences from school.

Secondly, sleeping in doesn’t give back the benefits of the stages of sleep you’ve skipped out on. Even if you get more hours of sleep on the weekend, Burhenne says, the additional hours won’t necessarily be the stages of sleep that allow your body to heal and restore itself, such as deep sleep and REM sleep. 

Finally, it can throw your hormones out of whack. If you stay up late and then sleep into the morning when there’s natural light, it can mess up your hormonal cycle, as well as the release of adenosine (ATP, the source of energy for your cells), notes Burhenne. 

In his personal experience, this can show up in your Oura App’s Sleep Score, too: “If I stay up too late and then sleep in late — even though I’ve gotten good staging, my deep sleep’s good, my REM is good — my Sleep Score may be about 4 to 5 points lower than if I’d gotten earlier in the morning.” 

5 Tips to Recover From Sleep Debt 

Trying to catch up on a sleep debt you’ve been building for months in one weekend is like cramming for an exam or crash dieting: You might see some results, but you’re better off creating new, healthy habits. Instead, turn to these strategies to establish a healthier sleep routine.

1. Take a (quick) nap. 

If you’ve accumulated an hour or two of sleep debt the night before, a brief nap can help pay it off (if you can swing it). Even a 10-minute nap can result in immediate improvements in cognitive performance and reduce fatigue, while 20-minute naps have been shown to improve physical endurance and reduce perceived exertion. 

Pro tip: “You shouldn’t nap more than 20 minutes,” in usual circumstances, Berhenne says. If you take a long nap, you might feel more rested, he says, but you’ll have more trouble going to sleep at your normal bedtime. Your nighttime slumber won’t be as restful, starting the sleep debt cycle again.

READ MORE: How Long Should You Nap For?

2. Maintain a consistent sleep schedule.  

Do your best to go to bed and wake up at the same time every day, Dasgupta says — yes, even on the weekends. This can help keep your circadian rhythms in check, so you’re able to fall asleep and wake up more easily.

And if you have a hectic life with lots of obligations, he says, avoid a new way people build up a sleep debt: revenge bedtime procrastination. Here’s the gist of that concept: After working a long day and into the evening, you want some time to yourself to wind down, watch a mindless TV show, or catch up with social media. Then, suddenly, you’ve spent hours looking at a screen and it’s way past your bedtime.

This is how sleep debt starts. The key, Dasgupta says, is compromise. To reward yourself for a long, busy day, maybe watch one episode of a show you’ve been wanting to binge, he suggests. Or maybe the reward is going to bed or waking up early on the weekend and getting some exercise with your family.

3. Keep a sleep diary — or use Oura Tags.

This isn’t just a sleep log with bedtime and wake times, Dasgupta says. A sleep diary should also include things like what you ate that day, whether you exercised, or how stressful work was. “This will help you get a rough estimate about which nights are going to be good nights and bad nights,” he says. 

This is where Oura can help: By using the Tags feature, you can make notes of your meals and other behaviors, such as workouts, hard days at work, or having a cold, to see how they correlate to sleep.

You might notice that on days when you have caffeine after a certain time, your sleep suffers. Or when you eat later, you don’t feel as rested. All this information will help you improve your rest each night so that you can get out of the sleep debt cycle.

4. Sleep in a super-dark environment. 

Blue light (the kind produced by your phone screen) is the same color as daylight, and it messes with your brain’s sleep signals. Instead of increasing the amount of melatonin being produced in your brain, which tells your body to go to sleep, blue light suppresses the release of this hormone. When you don’t have enough melatonin, you won’t be able to sleep.

READ MORE: Everything You Need to Know About Melatonin

5. Wake up earlier, instead of staying up later.   

If you must cut into your sleep time to do extra work (or squeeze in “me” time), trade late nights for early mornings. Doing so will allow you to go through all the important stages of sleep, Burhenne says, and make it easier to fall asleep the next night, too: “The next night, you’re tired, and you’re able to go to bed at the same, normal time.”

READ MORE: Deep Sleep: What Is It and How to Get More

About the Oura Expert

Raphael Vallat, PhD, is a senior machine learning data scientist at Oura. He previously worked as a sleep researcher in the Center for Human Sleep Science at University of California Berkeley (Prof. Matt Walker‘s lab). He has published extensively on the topic of sleep and human health, and his work has been featured in several major news media and podcasts. In his free time, you can find him enjoying precious moments with his amazing wife and daughter, playing music, or hiking with friends.