Verified by 
Key points
- Estimates indicate that humans may be able to survive 2 to 10 years of total sleep deprivation before dying.
- There are no recorded human fatalities directly attributable to either insomnia or to lack of sleep, except for in very rare cases.
- However, indirect death caused by errors related to impaired cognitive functioning from lack of sleep—say, while driving—is possible.
"I just don't understand it. According to the history given by her friend, she hasn't slept in eight days and there have been no behavioral indications that she has slept since being admitted. We'll need to get an EEG as part of the workup. "
"Hard to believe. How long can this go on?"
"Well, 10 days without sleep and death ensues..."
If you are familiar with the hit TV show House, you will recognize that in the dialogue above, I borrowed heavily from an episode about a patient with potentially fatal insomnia. (For some interesting reviews of the show from a medical standpoint, see House Medical Reviews.) The impact of this program is so great that I have had exhausted patients express concern that their death is imminent because they were nearing the fatal tenth day without sleep! Is this possible? Are there documented cases of this happening? And is this really "insomnia" we are talking about?
Insomnia vs. sleep deprivation
First of all, insomnia and sleep deprivation are two different things. Insomnia, according to the International Classification of Sleep Disorders, is "a repeated difficulty with sleep initiation, duration, consolidation, or quality that occurs despite adequate time and opportunity for sleep and results in some form of daytime impairment." This means that despite having enough time and opportunity to sleep, there is difficulty falling or staying asleep or sleep is non-restorative. Daytime problems associated with insomnia are well-known and include irritable or depressed mood, fatigue, and cognitive difficulties.
In contrast, sleep deprivation involves getting less than a sufficient amount of sleep, either acutely or chronically, and results in difficulty with attention and concentration, decreased motivation, depressed mood, and daytime sleepiness. The cognitive effects of sleep deprivation are greater than for insomnia. It can be hard to think straight when you have missed a night of sleep. In any case, there are no recorded human fatalities directly attributable to either insomnia or to lack of sleep. There is, however, a rare disease with associated insomnia that does result in death that is described below.
Second, insomnia is a problem of over-arousal or an overly active awake system while sleep deprivation results simply from not getting enough sleep. Insomnia affects millions of people, is the most common sleep disorder diagnosis, and is highly treatable. Sleep deprivation can result from a number of causes. For example, from a lifestyle that chronically fails to allow sufficient time for sleep, or from an acute situation such as combat, or from being in a crisis situation such as being lost at sea and being unable to sleep while treading water.
The reported effects of sleep deprivation
Despite the wretched feelings that accompany insufficient sleep, it is clear that sleep is, at least at first, relatively easy to do without. In fact people today are often sacrificing sleep to have more time for other activities. Indeed people seem to be able to function with very little sleep for prolonged periods of time, albeit not happily.
Randy Gardner in 1964 showed that even after 264 hours (11 days!) of total sleep deprivation he was able to continue to function. With a relatively short period of recovery sleep (about 14 hours) he showed no lasting negative effects.
Even longer periods of sleep deprivation have been reported. Results of experiments using completely sleep-deprived rats indicate that very prolonged sleep deprivation could result in death but this has never been observed in humans. Estimates indicate that humans may be able to survive 2 to 10 years of total sleep deprivation before dying. Of course, indirect death caused by errors related to impaired cognitive functioning—say, while driving—is another story.
Rare conditions
There are very rare conditions associated with genetic abnormalities that can result in a relentlessly progressive illness involving insomnia that ends in death. For example, fatal familial Insomnia is an illness in which the victim initially has difficulty falling and staying asleep, lapses from quiet wakefulness into sleep with the enactment of dreams, and has loss of deep sleep. The illness relentlessly progresses with symptoms such as excessive salivation, rapid heart rate, rapid breathing, tremor, and eventually coma and death. Death occurs 8 to 72 months following the onset of the illness.
In the end, it must be noted that we can often go a long time with little or even no sleep and continue to function. Surgeons, medical interns, military personnel, and truck drivers often function on very little sleep. However, they are not typically happy about it and accidents due to cognitive errors tend to increase in frequency with decreasing sleep. Many of us have had the experience of forgetting to make that left turn when driving after a night of too little sleep. Being sleepless in America, or anywhere else, feels bad.
But- there is good news! If you suffer from insufficient sleep, some lifestyle changes may be all that is needed to restore healthy functioning. And if you suffer from insomnia, you can rest assured that your life is not on the line and that treatment is available. For optimal functioning, health, and quality of life, nothing beats a good night's sleep.
