what is sleep debt

Some days (or weeks) it’s just too hard to get a full night’s sleep. Maybe you’re up early because of a major project at work. Or you’re a new parent who gets awakened every few hours throughout the night.

All those nights of disrupted or less-than-adequate sleep add up, resulting in what’s known as sleep debt. If you haven’t heard of sleep debt before, it’s a real thing.

What Is Sleep Debt?

Sleep debt is the accumulated loss of sleep that occurs from not getting enough sleep over several nights or longer.
Before you can determine whether you’re in debt when it comes to sleep, you need to know how much sleep you should get each night. The American Academy of Sleep Medicine recommends that adults get at least 7 hours of sleep each night. This includes older adults: Elderly people may have more trouble sleeping, but they need just as much sleep as younger adults.

The National Sleep Foundation recommends that adults age 18 to 65 get between 7 to 9 hours of sleep. Those 65 and older should get 7 to 8 hours each night.

Not meeting your sleep needs for a night or two is usually okay. Any longer stretch and it will start to impact you.

If you’re shortchanging your sleep consistently, you’re not alone. One-third of U.S. adults report usually getting less than the recommended amount of sleep, according to the CDC

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How Is Sleep Debt Calculated?

One way to calculate your sleep debt is to track the nights you’re getting less than 7 hours of sleep. Then add up how much less sleep you got every day. So if you’re only getting 6 hours of sleep Monday through Friday, by the weekend you’ve built up a debt of 5 hours.

That’s the bare minimum, because everyone’s sleep needs are different. What’s more important is knowing what your body and mind need— 7 to 9 hours of sleep—to function at their best. The goal is to wake up feeling refreshed.

If you feel your best after 8 hours of sleep, but sluggish after 7, that means you need 8 hours of sleep each night. Anything less than that adds to your sleep debt. In this case, getting 6 hours each weeknight means you have a 10-hour sleep debt by the weekend.

Health Issues Associated with Sleep Debt

Consistently falling short on sleep has negative consequences for your health. With just a few days of lost sleep, you have trouble concentrating, your blood pressure increases, and your immune system starts to weaken.

Continued sleeplessness contributes to major health problems down the road. That’s because there’s a link between getting enough sleep and having obesity, depression, type 2 diabetes, and heart disease. Adults getting less than 7 hours of nightly sleep are also more likely to smoke, abuse alcohol, or be physically inactive.

And there’s the socio-economic cost, including loss of productivity from sick days to difficulty focusing at work. Chronic sleep deprivation can also contribute to workplace accidents.

Feeling sleepy can also increase your risk of being in a car accident. Drowsy driving causes an estimated 100,000 to 325,000 vehicular crashes each year, according to the National Safety Council. And those crashes lead to an estimated 1,550 to 6,400 deaths.

How Long Does It Take to Recover From Sleep Debt?

There’s no quick answer on how long it takes to erase a sleep deficit. Getting to a healthy sleep balance depends on the severity of your sleep deprivation.

One good night’s sleep can’t make up lost sleep over several nights. But it can get you on your way to erasing the negative effects of accumulated sleep loss. It may take several nights of consistently good sleep to overcome a sleep deficit.

The Harvard School of Public Health recommends adding one to two hours of sleep each night to make up for a short-term debt. Add two extra hours each night over the weekend and an extra hour each night during the week until you’re caught up. This can work well for the five to ten-hour sleep debt mentioned above.

For longer sleep loss, a vacation may be in order. Give yourself a chance to turn the alarm off and sleep until your body wakes naturally.

Can Napping Help Make Up Lost Sleep?

Napping can both help and hurt sleep debt.

If you didn’t get enough sleep the night before, a nap can help you feel less sluggish during the day. Keep your naps short. Aim for 10 to 20 minutes.

However, longer naps can lead to post-nap grogginess. Rather than feeling refreshed, you feel more tired.

If you do nap, be sure to nap earlier in the day. Late afternoon naps or those too close to bedtime can disrupt sleep and worsen insomnia. Take a nap no later than halfway between the time you wake up to the time you go to bed.

Repaying Your Sleep Debt

It’s far too common for us to get busy and put off sleep, thinking we have too many important things to do. But sleep is essential to our overall health, and we need to make it a priority to meet all the demands on our time.

You may not be able to make up for all the sleep you’ve lost, but you can take steps to repay your debt. Make sleep a priority throughout the week by going to bed at the same time every night and waking at the same time every morning. Thinking you will sleep in and make it up over the weekend doesn’t always erase the harmful effects of lack of sleep.

To repay your sleep debt, you need to allow your body a chance to go through its usual sleep cycle. You have five phases of sleep, from light sleep to deep sleep and REM, which is when dreaming happens. Your body usually goes through multiple REM phases every night.

Help your body fall asleep by skipping coffee or alcohol before bedtime and opting for a glass of warm milk instead.

When Should You See a Doctor for Help With a Sleep Debt?

If you can’t get consistent, adequate sleep, there can be something else going on beside work or life issues. You may have a medical issue that a doctor should address. You should see a doctor for sleep debt if you experience these common sleep disorders.

  • Insomnia. This is when you have trouble falling asleep or staying asleep. In some cases insomnia causes you to wake up earlier than you planned, but you can’t get back to sleep.
  • Sleep apnea. It’s a serious sleep disorder where your throat intermittently collapses during sleep. Excessive snoring and daytime sleepiness are signs of sleep apnea. Sleep apnea can contribute to poor or disrupted sleep.
  • Restless leg syndrome. RLS causes you to experience a “crawling” sensation in your legs. You can also get leg cramps or experience leg jerks.

These aren’t the only reasons to see a doctor. If sleep debt is getting in the way of your daily functioning, see your doctor. They can help or refer you to a sleep medicine doctor.

About Sleep Medicine

Sleep medicine is a medical specialty focused on sleep health. Sleep medicine doctors diagnose and treat sleep disorders and disturbances.

UPMC’s Sleep Medicine Center — accredited by the American Academy of Sleep Medicine — is the only multidisciplinary sleep medicine facility in western Pennsylvania. If you are struggling because of a sleep disorder, such as restless leg syndrome, insomnia, or sleep apnea, contact us for help. Our experts can help uncover the problem and get you back on a regular routine.

About Sleep Medicine

Millions of Americans struggle with disorders that prevent them from getting a good night’s sleep. Better sleep can lead to better overall health, and the UPMC Sleep Medicine Center is here to help. We diagnose and treat numerous sleep conditions or disorders. We also provide help to people suffering from lack of sleep because of other health problems. We recognize a lack of sleep can cause problems during other times of the day, including alertness, memory, and health immunity. We hold sleep studies and lead clinical trials, all in the name of helping you sleep. Find a provider near you.