If you think the only debt you can get into is with your credit cards, think again. When you’re sleep deprived, you experience something called “sleep debt.” “This refers to the condition where we don’t get as much sleep as we need over a period of time, and the physical need for sleep increases to make up for this,” explains Michael Grandner, PhD, MTR, director of the Sleep and Health Research Program at the University of Arizona College of Medicine. The concept of sleep debt represents all that snooze time that you didn’t get.
But unlike a financial debt, you can’t pay back a lack of time in the sack. That is both good news and bad news. The good? If you spend a year getting an hour less sleep than you should, it doesn’t mean that you now need to sleep for two weeks straight to make up for it. “Rather, it’s more like your diet. If you eat nothing but cheeseburgers for a week, eating nothing but kale and brussels sprouts for the next won’t undo all of the damage you did,” says Grandner. “It can start tipping the scales in the other direction, but it’s not an even trade.” That brings us to the bad news: you can’t trade a bad night for a good night. So it’s not just a matter of paying yourself back for the time you borrowed.
Here, everything you need to know about a sleep debt.
A Sleep Debt Does More than Make You Weary
Sleep debt can have serious health consequences that go beyond adopting a major coffee habit or feeling sleepy during the day. Research suggests that those of us who snooze for six hours or less, on average, are more likely to pack on the pounds and, if this sleep deprivation is chronic, become obese. Other potential health issues include hypertension, diabetes, high cholesterol, higher levels of systemic inflammation, greater risk of heart attack and stroke, as well as depression, anxiety, and stress. And that’s not all! “Short sleepers are more likely to drive drowsy, eat an unhealthy diet, smoke, and drink more alcohol,” says Grandner. “They also tend to be more dissatisfied with their lives, earn less money, miss more days of work and be less productive. And, as has been found in dozens of studies over 50 years, they tend to die sooner.”
There is A Lot Going On in Your Body When You’re Snooze Deprived
“Sleep is a major player in many important functions in the body, especially in the areas of regulation,” says Grandner. In fact, almost every system in the body, from the heart and blood vessels to the brain and the immune system, involve processes and networks of information exchange that keep all parts of the body humming along. When you’re suffering from a sleep debt, these systems start to become inefficient and have difficulty performing all of the proper maintenance. “In short, sleep is an important part of how our biology works, and not getting proper sleep—just like not eating a proper diet—leads to many different systems not working as well as they should,” says Grandner. “Sleep deprivation disrupts the immune system, repair and recovery, metabolism, attention, learning and memory, emotional regulation, regulation of hormones, and many other systems.”
You Can’t Make Up a Sleep Debt
In keeping with the diet analogy: “If you eat an unhealthy diet, loaded with empty calories, for five days, it takes more than a few salads on the weekend to make up for what you did. In the same way, you can’t pay yourself back the sleep that you took from yourself,” says Grandner. That said, just like diet, if you’ve spent years chowing on fast food and sugary snacks, the best way to get back on track is to make some long-term changes to your eating habits. Of course, as with diet changes, the results are often subtle and inconsistent so you won’t notice them at first, but overall you’re heading in the right direction for your health.
You Can Stockpile Sleep
Well, sort of stockpile it. When that work project, cross-country trip, or other sleep disruptor looms and you know you won’t be catching Z’s the way you should, you can do a little sleep debt prep. “If you make sure you are exceptionally well-rested for a few nights, you will be much more able to tolerate a short-term period of sleep loss,” explains Grandner. That said, there can be too much of a good thing. In other words, it’s not correct that the more sleep you get, the better. “There is such a thing as over-sleeping, and this is not a way to make yourself more resilient,” says Grandner.