You may have noticed an uptick in media articles about sleep as it relates to public safety. There’s concern among cultural analysts and economists that widespread sleep deprivation in the US—which leads to and increases sleep debt—has become as dangerous a public health issue as alcohol abuse.
What is sleep debt?
How many hours of sleep should we be getting? The National Sleep Foundation (NSF) in 2015 recommends adults sleep seven to nine hours nightly for optimum health.
To figure out one's sleep debt, the answer is mathematical: Take the number of nightly hours of sleep you should be getting, then subtract from it the amount of sleep you actually get. Keep records for 365 consecutive days, then look at the final amount. Those hours constitute your sleep debt for the year.
Even when you lose less than 30 minutes of sleep nightly, that accumulated loss still translates into more than two weeks of sleep debt a year.
Sleep debt results from chronic lack of sleep, or sleep deprivation. One in three Americans suffer from chronic sleep deprivation, according to the Centers for Disease Control.
"People accumulate sleep debt surreptitiously," says psychiatrist William C. Dement, founder of the Stanford University Sleep Clinic. It's quiet and sneaky; many of us may only notice it during the fall and spring time changes, when our systems are expected to adjust to clock time (as opposed to biological time). It is a key reason why we feel tired all the time.
Worst of all, it's cumulative. Make no mistake: sleep is, after healthy diet and regular exercise, the third pillar of health. When we accumulate sleep debt, we risk health consequences.
Why is sleep debt bad?
Just as lack of physical activity and poor diet are bad, sleep debt is bad. The body needs sleep just as much as it needs movement and food. One night without sleep may not permanently impact health, but chronic insufficient sleep can lead to behavioral and physical problems.
Behavioral problems caused by sleep deprivation include irritability, poor judgment, attention deficit, drowsy driving, memory issues, emotional stress, daytime sleepiness, poor risk management, depression and workplace accidents. People with high sleep debt do poorly on intelligence tests, while their beliefs in superstition and magical thinking increase.
Physical problems related to poor sleep include physical stress, immune system dysfunction, worsened vision, reduced motor dexterity, weight gain, advanced aging, cerebral shrinkage and systemic inflammation. The last problem—systemic inflammation—leads to major health problems like diabetes, cardiovascular disease and stroke.
What we lose when we lose sleep
A critical stage of sleep, Rapid Eye Movement sleep (REM), can be compromised for the sleep deprived. REM occurs mostly in the night's second half, its longest stretches taking place in the very early morning.
REM sleep allows our brains to consolidate information, process memory and learning, and repair and restore neurological processes. REM is so important that, if a person is deprived of several nights of it—then is given the opportunity to re-engage in REM sleep—they will encounter long phases of “REM rebound” as the brain resets and clean up.
Who has sleep debt?
It’s hard to test for sleep debt, but a close look at lifestyle, behavior and preexisting health conditions can offer clues.
Lifestyle can have a critical impact on sleep. People who work night or overnight shifts probably have sleep debt. New parents of infants often have sleep debt. Students who pull “all nighters” probably have sleep debt.
If you don’t keep regular sleep hours, if you stay up late using an electronic device with a screen, if your sleeping environment is not conducive to good sleep, if you have pets that interrupt your sleep at night… you probably have sleep debt.
And if you do, then you join the eight out of 10 Americans from a Better Sleep Council study who feel they would have better energy daily with “an extra hour of sleep.”
Unfortunately, the idea that sleep is a "bank" you can deposit to and withdraw from is misleading and inaccurate. You cannot sleep ahead and store it for later. Neither can you avoid sleep for days on end and expect sleep debt not to accrue.
How to know if you have sleep debt
Aside from getting the recommended seven to nine hours of nightly sleep, the NSF has also created a self-checklist for people to reference if they suspect they have sleep debt. If you can answer yes to any of these questions, you might consider getting help for your sleep deprivation.
- Are you productive, healthy and happy on seven hours of sleep? Or does it take you nine hours of quality ZZZs to get you into high gear?
- Do you have health issues such as being overweight? Are you at risk for any disease?
- Are you experiencing sleep problems?
- Do you depend on caffeine to get you through the day?
- Do you feel sleepy when driving?
How to avoid sleep debt
Prioritize sleep to avoid sleep deprivation. Every night you shortchange yourself of sleep, you add to your debt.
Weekend sleep catch up is perhaps the most popular solution, but the payoff isn’t necessarily 1:1. In other words, if you are short an hour of sleep a night from Sunday through Thursday, that’s five hours of sleep lost. However, you won’t need to sleep an extra five hours on Saturday morning to fix that.
Nor would you want to. Excessive oversleeping messes with circadian rhythms in a way that leads to “Monday morning hangover” or “social jet lag.”
But sleeping one extra hour on both Saturday and Sunday can help you benefit from one more REM cycle. Also, going to bed a little earlier or taking a nap can help.
Even so, busy weekends can still interrupt these efforts. Good sleep hygiene practices can help:
- Avoid screens at bedtime (smartphones, tablets, all handheld devices). If you like to read at night to relax, invest in a blue-light blocking screen or “blue blocking” reading glasses for your electronic reader, or use a non-backlit device.
- Don’t exercise right before bedtime; it alters your body chemistry enough to make it difficult to fall asleep.
- Large meals eaten right before bed can cause various digestive problems that fragment sleep.
- Working on either physical or intellectual tasks hinders the body and brain’s need to prepare for sleep.
- Go to bed when you are tired, then allow yourself the opportunity wake up without an alarm clock (if your lifestyle allows). Maintain this practice for several days, if possible; it's a slow but steady way to erase sleep debt.
- Use an alarm clock and get out of bed at the same time every day. This is another way to force a reset of your circadian rhythms.
Finally, if you have health concerns or suspect you have a sleep disorder, get it checked out.
Dr. Dement says, "When you put away sleep debt, you become superhuman.” Want to feel like this again? Make sleep quality and quantity a priority.