How Long Can You Go Without Sleep?

Approximately 264 hours or just over 11 consecutive days are the longest recorded time without sleep. Although it’s unclear exactly how long humans can survive without sleep, it isn’t long before the effects of sleep deprivation start to show.

You can start to hallucinate after just three or four nights without sleep. Long-term deprivation of sleep can lead to

• paranoia

• psychosis

• cognitive impairments

• delusions

• irritability

Although it is extremely rare to die from sleep deprivation, it may happen.

What to expect after 24 hours without sleep

Missing 24 hours of sleep isn’t uncommon. You might miss a night of sleep to work, cram for a test, or take care of a sick child. While it might be unpleasant to stay up all night, it won’t have a significant impact on your overall health.

Still, missing a night of sleep does affect you. Studies have compared 24-hour wakefulness to having a blood alcohol concentration of 0.1 percent. This is above the legal limit to drive in most states.

Some effects of going 24 hours without sleep include:

• altered perception

• decreased hand-eye coordination

• drowsiness

• increased risk of accidents or near misses

• increased muscle tension

Symptoms of 24-hour sleep deprivation usually go away once you’ve had some shut-eye.

What to expect after 72 hours without sleep

Many people experience an irresistible urge to sleep after 72 hours of sleeplessness. Those on their own are unable to stay awake.

Going three days without sleep profoundly limits the ability to think, especially executive functions such as multitasking, remembering details, and paying attention. This level of sleep deprivation can make it difficult to see even simple tasks through to completion.

Emotions are also affected. People who have experienced this lack of sleep can be easily irritated. We may be discouraged, nervous or paranoid. Evidence has also found that lack of sleep makes handling the feelings of others more difficult. In one study, participants with 30 hours of sleep deprivation had difficulty recognizing angry and happy facial expressions.

Finally, several days of sleep deprivation can significantly alter perception. You might experience hallucinations, which occur when you see something that isn’t there. Illusions are also common. Illusions are a misinterpretation of something that’s real. An example is seeing a sign and thinking it’s a person.

The bottom line

It isn’t clear how long humans can truly survive without sleep. But it is clear that extreme symptoms can begin in as little as 36 hours. This includes a reduced ability to think, poor decision-making, and speech impairment.

Pulling an all-nighter once every couple of months likely won’t do any long-term damage. But if they’re happening more often — intentionally or not — talk to your doctor.

If you’re staying awake out of necessity, your doctor may be able to offer advice on how to do so in the most health-conscious way. Otherwise, your doctor can get to the root of your symptoms and help you get your sleep schedule back on track.