Skip to main content

Verified by Psychology Today


Are You Building Up Sleep Debt?

Ignoring sleep deficits can invite trouble.

sleep, sleep deprivation

This article is a guest post by Stanford college student Doniel Kaye. Sleep deficits can contribute significantly to emotional problems like depression, anxiety and quickness to anger, to ineffective work performance, and even to relationship and marriage problems, so the topic struck me as an important one.

I welcome submissions for consideration as guest posts. Please submit via my website at

Sleep Negligence: A Dangerous Mistake, by Doniel Kaye.

It's 6:00 a.m. on a Sunday morning. Jim jumps out of bed and hits the road in hopes of catching first tracks in the Colorado high country. As Jim drives toward the peaks, his buddies chatter enthusiastically about the upcoming adventure. However, after an hour on the road, this effusive outburst subsides. In the quiet of the now-sleeping friends, Jim begin to feel drowsy. He quickly refocuses his attention on the road and turns on the radio. The tunes keep him awake for a while, but soon after, he begins to feel his eyes droop once more. Frustrated and alarmed, Jim exits the highway and makes a stop at the closest gas station. He’s relieved at having avoided a disaster.

While buying himself a cup of coffee, Jim muses aloud to his now-awakened buddies how odd it seems that he feels so tired. After all, he was on his way to go skiing, his favorite activity. One of his friends asks about his past week. Jim recalls that the week had been abnormally hectic and full, in part because he ‘d put in extra hours of work to free up his weekend for skiing.

Ironically, Jim realizes, cramming and working late at night in anticipation of the weekend mountain trip may have been responsible for a near catastrophe.

As a long-time Colorado native and a current student of sleep science pioneer Dr. William Dement, I resonate personally with this vignette. Students of the sleep doctor espouse the phrase "Drowsiness is red alert!” when they hear stories like this. This mantra admonishes drivers to be aware that when they must exert a conscious effort of will to keep themselves awake, they should be alarmed. They’d best pull off the road immediately. The mortal and immediate dangers of driving while sleep-deprived are striking. Sleep science reveals that susceptibility to automobile accidents is but one small example of why sleep knowledge and prioritization is of cardinal importance.

Sleep terminology

Like hunger, the sleep drive is powerful and crippling when not sated. In a given twenty-four hour period, people naturally alternate between alertness and drowsiness with periods of peak alertness occurng during daylight hours and periods of drowsiness during the night.

Each person is endowed with a sleep regulator known as a sleep homeostat. The sleep homeostat regulates sleep drive in response to the size of sleep debt, that is, the extent of deficiency in the total amount of sleep required. Sleep drive goes up with a large sleep debt, much like determination to repay bank loans may go up the more you find yourself in financial debt. The average person needs about eight hours of sleep a day to balance the sleep hemostat and avoid accruing sleep debt.

The Opponent Process Model describes how physiological forces mediate sleep and wakefulness impulses. The body is equipped with an alertness signal known as Clock Dependent Alerting (CDA), which is associated with peak performance and alertness. This alerting signal is opposed by the sleep inducing mechanism of sleep homeostasis or sleep debt, which increases in force throughout the day. These forces control the routine alternations of drowsiness and alertness that we experience on a daily basis.

Back to the weekend ski trip.

During Jim's drive up to the high country, sleep debt, which had ballooned over the course of his intensely packed week, had overpowered his CDA, his internal mechanism for maintaining alertness. Unable to keep himself awake while performing a dull task, he drifted off. Sleep homeostasis was responsible for his drowsiness.

But hold on just a moment! Jim had sprung out of bed and seemed to have abundant energy in the early morning. He was bursting with excitement at the start of his trip. If the drive to sleep was so large, how could he have been so alert at the onset of the ski expedition?

Jim was fooled by a momentary increase in alertness that occurred in spite of his sleep debt. CDA counteracts feelings of drowsiness associated with sleep debt. Additionally, stimulation in the form of light and social interactions can counteract drowsiness. But CDA is fleeting and stimulation is but a temporary antidote to the overwhelming effects of a large sleep debt. The only way to restore balance to the opponent process and to keep sleep homeostasis at bay during active hours is through extra sleep. There is no other way to satisfy a sleep requirement. Sooner or later, the hours must be made up or you will continue to function sub-optimally. Sleep debt is real and its effects are real.

What's the big deal about sleep debt?

Driving safety is just one of many reasons why getting adequate sleep is critical. We lead busy lives. We have demands and responsibilities. We have tasks and pleasures that we need and want to get done. Sleep debt, which impairs our ability to be highly alert and aware, hampers our ability to perform at our best in these daily tasks.

This decrement can be devastating to the aspiring student and to working people as well. Fighting sleep debt while trying to concentrate interferes with performance, so work capacity is impaired.

Frustration and moodiness from sleep debt also can have severe social repercussions. We might feel and appear to be lethargic in social interactions, or emotionally brittle, irritable and short-tempered. The extra effort we must exert in order to function during the daytime detracts from all our life endeavors, detracting from our satisfaction and contentment with our lot.

The consequence of long-term sleep deficits can be all the more serious. Heart problems, diabetes, stroke and memory problems are among the many potential distinctly undesirable health risks.

Fortunately, new routines with adequate hours of high quality sleep can remedy these problems.

At the same time, while sufficient sleep is vital, changing established habits to create more reliable and healthy sleep patterns is not easily done, especialy for college students like myself or for adults whose work responsibilities or pleasure activities lead to too much doing and not enough resting.

The requisite amount of sleep and the ideal sleep schedule varies from person to person. Naps can be effective in restoring alertness to many who might experience drowsiness and ebbs in energy during the afternoon hours. Many people however still function best by satisfying their full sleep requirement in consecutive hours.

What about the proverbial "one good night's sleep?" Harvard researcher Daniel A. Cohen, in a 2010 sleep study, observed nine college student participants who were asked to sleep only limited hours for three weeks, alternating with occasional long sleep nights. Cohen found that there's truth in the good-night's-sleep belief, and also error. One good night's sleep does pep up the sleeper for several hours of increased alertness and ability to perform cognitive tasks the next day. At the same time, even if the person no longe feels tired, the underlying accumulated sleep deficit remains until the debt has been fully repaid in the requisite total number of sleep hours. The body is like a banker that keeps close tallies of rest in and awakeness out of our sleep accounts.

How much sleep is enough sleep?

The required amount of sleep varies with individual biological factors and also with age. Indeed some people simply do not need as much sleep as most do to be able to be alert and fully functional when awake. With regard to age, infants sleep most of the day and night with only brief periods of alertness. Children and adolescents need more sleep than adults as critical processes involved in the process of growing occur during certain sleep stages.

As diurnal creatures, our biological clocks work best when aligned with the 24 hour light and dark cycle. Light serves as a natural stimulant to induce the waking state. Traditionally, people performed most of their activities also during daylight hours. The modern era of electricity has changed this natural cycle. People are active and exposed to light from artificial bulbs. TV and electronics lure people away from sleep during the dark hours. In addition to sleep deficits, further problems associated with unsatisfactory sleep stem from disruptions to the natural circadian rhythms which roughly correspond with the natural 24-hour light and dark cycle. Modern society and technology have definitely changed the game. Now people's biological clocks often conflict with our perpetually awake and active world.

Elements of the S.E.L.F. Correction Model

Social interactions, exercise, light, and food—can be used to regulate a sleeping schedule and sleep-awake cycle. Social interactions and light can keep a person alert and aware when peak performance is necessary. Regular mealtimes and a healthy diet coupled with sufficient exercise are also conducive to regular sleeping habits. Regularizing these activities can help to keep sleep debt at a manageable size.

Life is complex and unpredictable, and particularly busy times cannot always be anticipated. At the same time, during these periods, sleep does not diminish in importance to overall health, well-being and ability to function. So if meeting the sleep requirement is an impossibility, it can be helpful at least to limit the size of its ballooning by regarding sleep as a priority essential to effective work output, long-term health, and on-going life satisfaction.

Ready to throw out your alarm clock and instead trust your body? Establishing consistent and adequate sleep hours and then waking up naturally may be the best indicator that your body is getting the sleep it needs.


Denver psychologist and marriage therapist Susan Heitler, PhD is author of, a website that teaches the skills for relationship and marriage success.

More from Susan Heitler Ph.D.
More from Psychology Today