We are in the midst of a catastrophic sleep-loss epidemic, according to Matthew Walker, director of the Center for Human Sleep Science at the University of California, Berkeley. “No aspect of our biology is left unscathed,” he says. “It sinks down into every possible nook and cranny.”

He’s right, and students are one of the groups most susceptible to sleep deprivation.

A recent study provided some alarming insights into the sleeping habits of college students in the UK. The study showed that 71 percent of students failed to achieve the recommended 8 hours of sleep, with 60 percent classified as poor sleepers. Some disciplines fared worse than others. Architects averaged a mere 5.7 hours sleep, with sleepless nights due to academic work—colloquially known the world over as “all-nighters”—occurring 2.7 days a month.

How we sleep

The body initiates the sleep cycle in two ways: first, it pumps up the circulating levels of a neurotransmitter called adenosine, and second, it establishes an ideal bedtime for us to follow by using the circadian clock to send signals to the rest of the body.

Understanding the nitty-gritty of the science isn’t necessary to know that adenosine helps act like a dimmer switch for the brain, lowering the intensity of processes like wakefulness, attention, memory, and reaction to physical stimuli—the things your brain needs to shut down to get a good night’s sleep.

(Fun fact: caffeine helps keep us awake by antagonizing adenosine receptors in the brain).

When we wake up after a restful night of sleep, the levels of circulating adenosine plummet and we are, consequently, more alert.

As for the circadian clock, most people know that it regulates the pattern of sleeping and waking during a cycle of roughly 24 hours. But it also controls fluctuations in blood pressure, body temperature, various hormones and digestive enzymes. We’re typically at our sleepiest between 12 a.m. and 6 a.m.

And what happens when we don’t

Without optimal sleep, students can seriously impede their ability to succeed in their courses. They experience a three-pronged reduction in their ability to retain information, stay focused, and cope with stress, which in turn can have a serious impact on academic performance.

To give an idea of how important even a single hour of additional sleep can be, a study performed by economist Teny M. Shapiro of Santa Clara University suggests that beginning classes just one hour later can have the same effect as either shrinking the class size by a third or replacing the teacher with one whose performance is one standard deviation higher.

And the deleterious effects of sleep debt go beyond the classroom: student-athletes who receive less than 8 hours of sleep get hurt more often, and car accidents due to drowsy driving lead to an estimated annual cost of $109 billion in the U.S., not including property damage.

Sleep debt

While trying to get a good night’s sleep tonight could undoubtedly help the red-eyed night owl be more awake in tomorrow’s early-morning class, on a long enough timeline, poor sleep habits lead to something called “sleep debt,” where every night spent under the recommended number of hours of sleep begins to add up—like credit card debt.

A study done at the University of Pennsylvania and Harvard Medical School further shows the risks associated with poor sleep, but with an interesting twist: there seems to be a relationship between the number of nights with sub-optimal sleep and the degree of performance reduction.

Over the course of two weeks, sleepers in the study split into groups: one group slept the recommended eight hours, one group slept six, one slept four, and one went three days at a time without sleep.

While the group that slept eight hours maintained consistent performance, the more days the two middle groups of four and six hours spent in the study, the closer their scores got to the group with no sleep—whose ability to perform cognitive and physical tasks was, understandably, quite limited. 

How to prevent sleep debt

Walker believes that part of helping a sleep-deprived world get more shut-eye is by separating sleep needs from the stigmas of laziness.

“We want to seem busy, and one way we express that is by proclaiming how little sleep we’re getting,” he says, likening sleep deprivation to a badge of honor. “When I give lectures, people will wait behind until there is no one around and then tell me quietly: ‘I seem to be one of those people who need eight or nine hours’ sleep.’”

Here’s how you can prevent sleep debt from accruing in the first place:

Try to avoid naps, unless they’re absolutely necessary: people who work night shifts, or self-defined night owls, could pay back some debt by taking naps. However, naps can also interfere with one’s capacity to have a good night’s sleep, so the return on investment often isn’t worth it.

Make your bedroom a sleep sanctuary, primed for activities associated with rest and relaxation. Enforce embargos on working in bed and get rid of all phones, TVs, and computers. Replace these distractions with pleasure reading, meditation, and intimate moments as needed.

If you need to drink coffee, avoid caffeine intake after noon. And while you’re at it, go light on alcohol; research shows it wreaks havoc on your sleep cycles.

Shut off the lights, especially electronic screens, before bed. “We electrified the night,” Walker says. “Light is a profound degrader of our sleep.”

Staying fit can help facilitate sleep, but avoid exercise within three hours of bedtime.

If none of the above strategies help, consider discussing the problem with a doctor. You might have a condition called sleep apnea, which affects breathing regularity during sleep, or you might be experiencing clinical depression.

How to pay off your sleep debt

For those who fear they’ve already accrued a significant amount of sleep debt, the process of paying off that debt might seem daunting. However, a step-by-step approach, focused first on settling short-term debt and then addressing larger issues, can help.

In the short term, if you’ve missed 10 or more hours of sleep during the week, try to add three or four extra hours on the weekend, plus an extra hour or so the following week until you’ve made up the difference.

To address debt accrued long term, over the course of years, or even decades, the answer isn’t found in completing high-level math equations to figure out how many hours you lost and then pinning those hours to your current sleep habits.

Instead, take a more global approach, focused on establishing a baseline of rest, and then tweak your sleep schedule to allow for longer, more natural sleep. Take a vacation, ideally one light on responsibility and heavy on sleep. From there, consider turning off the alarm clock, at least at first, just to see how long your body naturally needs to get its rest.

At first, your body might need longer sleep than seems practical, but after a while, you’ll find a baseline that’s more in line with the eight-hour guideline.

But perhaps most importantly, do not go back into sleep debt. Once you’ve figured out how long you need to sleep, adjust your schedule accordingly, even if it means going to bed early to make up for early-morning work start times.