Roughly 1 in 3 adults suffer from sleep debt on a regular basis, according to research from the CDC. And given that the data is based on self-reported stats of whether or not people get 7 hours of sleep per night, it’s very likely the actual numbers are significantly worse.
When you don’t sleep as much as you need to, you start to accumulate sleep debt. Also known as a sleep deficit, sleep debt is the difference between the amount of sleep your body requires and the amount you actually get.
Sleep debt builds up over time, so by sleeping less than usual for multiple nights in a row your sleep debt can progressively get worse and worse.
The National Sleep Foundation recommends adults get 7-9 hours of sleep each night. However, an individual’s nightly sleep needs vary due to a number of factors (more on this later). When you don’t meet your nightly sleep need and sleep debt starts to accrue, you begin to become sleep deprived.
In the short term, the side effects of sleep deprivation may include:
Over the long term, chronic sleep loss can lead to:
“The way sleep debt works is that it follows you around for a few days,” says WHOOP VP of Data Science & Research Emily Capodilupo (Podcast No. 57: Naps–Your Greatest Recovery Amplifier). If you don’t catch up on last night’s lost sleep tonight, you’ll continue to feel the effects of it tomorrow.
And while you can’t go back in time and make up for past sleep that you’ve lost, there are several things you can do to counteract your recent sleep debt and set you on the right path going forward.
The obvious way to catch up on sleep debt is to go to bed earlier than usual (or sleep in later) and get more recovery sleep tonight. Since that’s often harder than it sounds, here are some other things you can do to help combat sleep debt.
If an earlier bedtime is not an option, the least you can do is try to spend more of your time in bed asleep. Things like avoiding screened devices in bed, lowering the temperature of your bedroom, and blocking out as much noise and light as possible can all help you get to sleep more quickly.
You’re not going to be able to fix 5 nights of poor sleep during the week with a couple good ones on the weekend. Additionally, altering your normal sleep patterns with a different schedule on the weekends throws off your circadian rhythm (the body’s 24-hour internal clock) and leads to lower quality sleep overall.
Conversely, a consistent sleep schedule where you go to bed and wake up at regular times each day reinforces your circadian rhythm and increases the efficiency of your sleep. In fact, locking in your sleep consistency can actually enable you to get more sleep while spending less time in bed.
If you can find a way to squeeze one in, an afternoon nap is often the most effective way to catch up on your sleep debt. For example, if you have an hour of sleep debt hanging over you from last night, a quick 30-minute snooze can cut that in half and boost your chances of making up the rest tonight.
WHOOP tracks your nightly sleep in detail, including the time you spend in each stage of sleep and your overall sleep efficiency (the percentage of time in bed that you’re actually asleep). Our Sleep Coach feature incorporates your physiology, amount of recent sleep, and the strain put on your body during the day to calculate exactly how much sleep you need.
Based on this, the Sleep Coach then tracks any sleep debt you accumulate and factors it into your sleep need the following night, making a recommendation for when to go to bed in order to best catch up on your sleep.