How long can you go without sleep?

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By Dr Simon Kyle

What's the longest you have gone without sleep?

Like breathing, sleep is a fundamental human requirement. It has even been said that one could survive for three times as long without food as one could without sleep. Indeed, one of the better known experiments on this subject, found that depriving rats entirely of sleep resulted in their death, or near-dying state, within 11-32 days (Everson et al. 1989).

Despite research such as this, there is still much which remains unexplained around the importance of sleep. In fact, in the study described above, it cannot be established that sleep deprivation was the cause of these animals' deaths. A number of the methods used in research can be identified as potential causes – the animals being wakened using an electric shock each time they lapsed into sleep, for example.

The question of how long a human can go without sleep remains unanswered by research. We are aware however, of cases outside scientific study where people have died after periods of no sleep at all.

Fatal familial insomnia
Fatal familial insomnia (FFI) is a rare, and ultimately terminal, genetically inherited prion disease. Once an individual begins to show the symptoms of FFI, starting with insomnia, the illness progresses quickly and further symptoms emerge. These symptoms include hallucinations, weight loss and finally dementia before their death.

The best-known case of FFI is that of Michael Corke, who died after 6 months of total sleep deprivation. As with the clinical experiments on animals, it is very difficult to determine whether lack of sleep is the definitive cause of death in people suffering from FFI. Thus, we cannot conclude that 6 months really is how long you can go without sleep before you die.

So, how long can you survive without sleep?
Ultimately, we do not know. Sleep science is a young discipline and only in the last few decades have we really started to make advances in our understanding of the importance and functions of sleep. In the 1960s a high school student named Randy Gardner set out to break the world record for the longest time spent awake. During the experiment he contracted problems with eyesight as well as various cognitive deficiencies, such as speech and memory problems (Ross, 1965). Towards the end of the experiment he also started to hallucinate. These symptoms emerged within just 11 days.

What we do know is that it is unwise to ignore our need for sleep. The negative side effects of partial sleep deprivation have been observed in in countless research studies and it is safe to assume that these would only be worsened by prolonged total sleep deprivation.


Everson, C.A., Bergmann, B.M., Rechtschaffen, A. (1989). Sleep deprivation in the rat: III. total sleep deprivation. Sleep, 12(1), 13-21.

Ross, J.J. (1965). Neurological findings after prolonged sleep deprivation. Archives of Neurology, 12(4), 399-403.

Filed under: Sleep science