Sleep deprivation occurs when you consistently fail to get enough sleep. An individual's need for sleep varies, but adults usually require eight hours, and younger people need nine hours of sleep each night. The more demands made on your time, the more likely it is you suffer from some degree of sleep deprivation.
There are various estimates of the number of Americans affected, but one reliable source says 20% of the population is affected every year. If that's correct, that means about 62.7 million Americans are currently afflicted with sleep deprivation.
Causes of Sleep Deprivation
Sleep deprivation can be acute (coming on rapidly, but ending quickly) or chronic (lasts a long time, or recurs periodically). There are three main causes of sleep deprivation: choosing to sleep too little, lack of time to sleep, and medical conditions.
Choosing not to sleep results in behaviorally induced insufficient sleep syndrome, if the patient has failed to sleep enough for a period of at least three months. That sounds easy enough to remedy, but the challenge is usually to convince the patient that more sleep is needed. In a society that places a high value on constant activity, sleeping is discouraged. It's viewed as a sign of laziness rather than a medical necessity.
Hucksters even promote methods of deliberately avoiding sleep, such as polyphasic sleep (taking multiple naps rather than succumbing to one extended sleep period). The use of stimulating drugs like caffeine, cocaine, or amphetamines in order to stay alert can also induce sleep deprivation.
Some people who feel constantly tired fear they have some illness, and are pleasantly surprised to discover the problem can be resolved by simply increasing their sleeping hours.
Too Little Time
Lack of time to sleep usually occurs in one of two ways. It can happen when people work too much (for example, at a company that requires a certain number of overtime hours per week), or when sleep time is consumed by tasks that must be done (for example, caring for a sick family member). Other than finding other employment or hiring a caregiver, alternatives that are not always available, this type of sleep deprivation is difficult to address.
Medical problems that cause sleep deprivation can be either conditions in which loss of sleep is a side effect, or primary sleep disorders that disrupt normal slumber as a main effect. If you have the breathing problem called sleep apnea, for example, that will wake you many times each night in order to prevent asphyxiation. Mental illnesses that cause manic states of hyperactivity can keep patients awake for long periods of time. The muscle tremors and rigidity caused by Parkinson's disease can interrupt sleep frequently.
Sometimes medications can cause loss of sleep, and consulting a doctor usually prompts an alternative prescription.
Insomnia, or an inability to sleep enough, can include trouble falling or staying asleep, as well as experiencing sleep that does not refresh. Some factors precipitating insomnia can be stress or poor sleep habits, and sometimes insomnia cannot be explained at all (idiopathic insomnia).
The difference between sleep deprivation and insomnia is that sleep deprivation means not having the chance to get a full night's sleep, and insomnia refers to not being able to take advantage of sleeping time by managing to fall asleep.
Effects of Sleep Deprivation
Range of physical and psychological negative effects associated with sleep deprivation, from minor (excessive daytime sleepiness, brief involuntary micro sleeping) to severe (increased risk of high blood pressure, obesity, heart attack, diabetes, cancer, and early death), even death itself (caused by a group of genetically linked fatal insomnias). Studies have showed rats denied any sleep will die in 17 to 20 days.
The uncontrollable urge to sleep often results in dangerous workplace or driving accidents. If you can imagine the risk posed by an air traffic controller, truck driver, or nuclear plant worker who needs sleep, you'll understand how the innocuous-sounding condition we call "drowsiness" can pose a serious hazard.
If you habitually operate on a sleep deficit, you'll need to overcome the following performance problems when completing tasks: difficulty in concentrating or even paying attention, physical desire to move around (to combat fatigue), increased reaction time, and clumsiness.
You'll be easily distracted, your decision-making ability will be impaired, your memory will move slowly, and you'll have to double-check everything you do to avoid errors. In short, it will be twice as much work to do what you normally do with ease, and your body suffers correspondingly.
The High Cost of Losing Sleep
The University of Maryland in 2010 gave the following estimates of the toll exacted each year in America by what one researcher calls the "24 hour, seven day" culture evolving in the national workplace:
- Direct costs: $16 billion
- Indirect costs: $50-$100 billion, which includes expenses sustained in sleep-related accidents, lawsuits, property damage, hospital bills, and death. The annual number of car crashes in that sum is estimated at 100,000
- Examples of industrial accidents in which loss of sleep played a part: Bhopal (gas leak), Challenger (disintegration of space shuttle), Chernobyl and Three Mile Island (nuclear disasters), Exxon Valdez (oil spill)
That's a staggering price tag, and as an annual expense it's a drain on the American economy.
Studies of Sleep Deprivation
Two Famous Case Studies in Total Deprivation
Experiments in total sleep deprivation produce startling, regrettable results. Take the case of Peter Tripp, a New York disc jockey who stayed awake for 201 hours broadcasting, as a publicity stunt. Tripp performed this feat first in a glass booth in Times Square, then in a hotel room with laboratory equipment monitored by medical personnel.
The longer Tripp went without sleep, the more medical assistance he required, because his brain gradually gave way under the strain. In three days, he developed inappropriate affect, or incongruous emotional reactions (laughing, anger) that didn't match the stimuli producing them. The next day, Tripp began to hallucinate, which soon progressed to full-blown paranoid psychosis.
Unfortunately, Tripp never made a full mental recovery, losing his job and his marriage due to conduct and attitude problems. The other famous subject of a sleep deprivation study, Randy Gardner (260 hours without sleep), suffered the same symptoms but did not experience lasting unpleasant effects.
Tripp was an older man at the time, and took amphetamines to stay awake, which Gardner did not do. For obvious reasons, studies of total deprivation of sleep are no longer performed on either animals or humans.
Sleep Restriction Studies
Now sleep researchers are interested in studying sleep restriction, measuring what happens to your brain and body when you get some, but not enough, sleep. These studies focus on either mental disruption or measurable physical changes, like altered hormone or neurotransmitter levels.
Sleep restriction studies have the potential to explain the wide range of symptoms observed in sleep deprivation patients, and quantify the health effects of what has become the common practice of sleeping too little.
Two Studies, One Conclusion
Two well-known studies of restricted sleep, conducted concurrently and designed to complement each other in terms of data gathered, gave the medical world a comprehensive picture of what happens if subjects sleep anywhere from three to nine hours per night. In considering those numbers, bear in mind Americans average 6.9 hours of sleep per night during the week.
Both studies used the same performance yardstick, a test called the psychomotor vigilance task (PVT) which measures reaction time during periods of pressing the space bar in response to a changing display on a computer monitor. The PVT is easy to do successfully for the well-rested, and is considered a predictor of workplace functioning.
Subjects sleeping eight or nine hours did consistently good work in the PVT, showing no changes as the studies went on. But the other groups, even the seven-hour sleepers, not only performed less well to begin with, but deteriorated in competence as the studies progressed. The effects were marked, in no way subtle, and the cognitive deficits induced by lack of sleep were serious enough that they would be noticeable on a day-to-day basis.
The available research states there are a few people who can sleep five hours or less each night, and there are others at the opposite end of the distribution who need nine to ten hours of sleep. But the eight-hour mark in the curve is where most human beings must fall in order to turn in a good performance, and too few of us currently achieve that standard.