What is Sleep Debt, and Can You Ever Pay it Back?

By: SleepScore Labs  |  October 7th, 2021

Sleep is the first thing we tend to readily sacrifice when our lives get busier than usual, when deadlines seem impossible to meet, or when we need a little extra time just catch up with friends and family. But why not when we can easily pay back lost sleep by staying in bed all through the weekend. Right? Not so fast. 

Sleep is a non-negotiable component to health and wellness. Research shows that it takes up one-third of our lives, and for good reasons too. Adequate sleep helps our body stay refreshed, replenished, and recharged after each day 

Numerous studies suggest that healthy sleep benefits our physical, mental, and emotional health. What amounts to healthy sleep? According to the Journal of Clinical Sleep Medicine, it involves: “adequate duration, good quality, appropriate timing and regularity, and the absence of sleep disturbances or disorders.” 

When we consistently sacrifice the “duration” and “regularity” of our sleep, we miss out on the vital features of healthy sleep. We also start to owe our bodies the remaining hours of sleep we’ve missed. This form of debt is what is known as sleep debt, or sleep deficit. However, a debt implies it’s something that can be paid back. And this may not be the case — what’s lost may, unfortunately, be lost. 

What is Sleep Debt?  

Sleep debt is the total sleep we need to make up for sleep loss or sleep deprivation on the body and mind. The Centers for Disease Control and Prevention (CDC) says that it builds up when we consistently don’t get enough sleep over several days. You then need sleep to pay back for lost sleep.  

Sleep debt can go unnoticed. Evidence suggests that you may get used to consistently depriving yourself of adequate sleep, so much that you may not be able to tell that you owe yourself some good sleep.  

So, what does sleep debt look like? Since it’s important to take a personalized approach to sleep requirements, sleep debt likely depends on multiple factors, from genetics to environmental factors, age, and even sex.  

For some people, it may look like the following scenario: The CDC recommends that the average adult gets at least 7 hours of sleep. If you get only 6 hours of sleep from Monday to Friday, you’d have accumulated 5 hours of lost sleep by Saturday: that is your sleep debt. However, some people need less or more sleep, depending on those previously described factors. So, if you’re finding it difficult to function at your peak performance and have difficulty concentrating, remembering things, or waking up feeling refreshed, one explanation may be insufficient or poor sleep quality built up over time.  

According to the Journal, Sleep Health, sleep debt is a new measure of adequate sleep that may help identify those at risk of insufficient sleep. Both partial sleep deprivation (having lower than usual hours of sleep during a 24 hour period) and total sleep deprivation (not having any sleep for a whole day) result in sleep debt and are associated with impaired physical and cognitive functioning, tiredness, excessive daytime sleepiness, lowered immune functioning, and increased risk of heart diseases, obesity, and diabetes.  

Risks of Falling Behind on Sleep 

One-third of American adults wake up every day feeling groggy because they haven’t had enough sleep. According to the American Sleep Association, 37.9% of US adults report dozing off during the day at least once in the past month, 4.7% report sleeping off while driving, and 35.3% have less than 7 hours of sleep daily. Not to even mention that 50 to 70 million Americans have chronic sleep-wake disorders. 

One thing is clear: there is a sleep deprivation pandemic, and many of us are falling behind on sleep. But what are the risks of accumulating sleep debt?  

Research suggests a connection between short sleep duration and 7 of the 15 leading causes of death in the US, including heart disease, cancer, accidents, stroke, diabetes, hypertension, and blood infection.  

According to the CDC, people who regularly sleep for less than 7 hours are more likely to report being physically inactive, obese, and a smoker than people who sleep for at least 7 hours every day.  

Reports from the National Highway Traffic Safety Administration state that drowsy driving primarily causes about 100,000 police-reported crashes every year—with these accidents resulting in up to 1,550 deaths, 71,000 injuries, and $12.5 billion lost.  

According to a review, just one sleepless night can worsen a person’s mood and lead to feelings of depression, anxiety, confusion, irritation, restlessness, anger, tiredness, and inertia.  Similarly, another study suggests that partial sleep loss for only two days may aggravate anxiety symptoms and poor mood and recommends getting sufficient sleep to support mental health.  

Additionally, the results of a 2018 study suggest that a small reduction in sleep time for just one night can reduce alertness, reaction time, and overall functioning during the day. Research also suggests that sleep debt may result in daytime sleepiness and impair physical and mental performance and immune health.  

Flowing from another study, restricting sleep to just six hours a night produces the same deficit in cognitive functioning similar to two nights of no sleep.  

Can I Catch Up on My Sleep Debt?  

If you’re one to give up sleep to catch up on pressing needs, you may be wondering: How do I get back my lost sleep time? It’s tempting to think that staying in bed all through the weekend may be the fix your body needs to reset and restore itself. The science suggests otherwise.  

study found that having one extra hour of sleep during the weekend to pay back sleep debt didn’t help manage weight gain and reduced insulin sensitivity associated with sleep loss.  

Another study suggests that a week’s recovery sleep isn’t enough to fill in for 10 days of partial sleep deprivation. The study showed that the recovery sleep only improved reaction time but had no impact on the behavioral and physical outcomes of sleep deprivation.  

And yet another study suggests that it takes four days’ sufficient sleep to recover fully from an hour’s sleep debt.  

What about taking naps during the day? Taking afternoon naps may enhance alertness, productivity, energy levels, emotion processing, learning, memory, and other cognitive abilities, but they cannot pay back your sleep debt.  

However, a study suggests that naps may help the body feel alert and refreshed after a night of inadequate sleep than coffee or extending sleep time for the following nights after restricting sleep.  

All’s not lost. According to the CDC, you don’t have to pay back your sleep debt by each hour of sleep lost. It may be enough that you regularly go to bed at a time that allows for at least 7 hours of sleep each night.  

Having a sleep debt may impact your well-being in numerous ways. Still, you don’t have to surrender to a life of chronic sleep deprivation. Following proper sleep hygiene will put you on the right path to complete recovery and optimal sleep health.  


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