How Long Can You Go Without Sleep?

4 Min Read | By Jessica Kadel

Last Modified 17 May 2022   First Added 3 January 2018

This article was written and reviewed in line with our editorial policy.

The body goes through a series of stages when experiencing sleep deprivation. With severe effects like hallucination, blackouts, and a weakened immune system. But how long can you go without sleep before these effects begin?

For many of us, sleepless nights are not a rare occurrence. Whether it’s your loved one’s snoring keeping you awake or caffeine-fueled nights of desperately trying to reach a deadline, sleep doesn’t always come as the top priority. But how long can you keep this up without dangerous consequences? And what’s the worst that can happen to your body and brain the longer you stay awake?

Here, we explore those exact questions and why you need your 8 hours’ sleep.

What happens to your body the longer you go without sleep?

Here are the exact stages your mind and body go through the longer you stay awake:

1 day without sleep

Rising levels of the stress hormone ‘cortisol’: Cortisol has an impact on many aspects of your body, but it primarily regulates your body’s stress response.

Increased blood pressure: According to the Mayo Clinic, “people with high blood pressure may have headaches, shortness of breath or nosebleeds.”

Cognitive impairment: This can affect judgement, memory and hand-eye coordination (the same as someone who’s had roughly 3 glasses of wine!)



2 days without sleep

Reduced metabolism: Decreased ability to properly metabolise glucose, which can cause weight gain and diabetes.

Blackouts: A blackout due to going without sleep can last between 1 and 30 seconds

Lowered temperature: This is your body’s way of telling you to rest.

Weakened immune system: When your immune system is weak, your body struggles to combat viruses, germs, and fungi.


3 days without sleep

Reduced concentration: If your concentration isn’t working the way it should, your motivation and perception levels will could all be out of sync.

Hallucinations due to a chemical imbalance in the brain: Hallucinations are visual sensations that appear to be real but are actually manufactured by the mind.

“Depending on the length of sleep deprivation, approximately 80% of normal people in the population will eventually have hallucinations.” – Brandon Peters, Neurologist

4+ days without sleep

Neurological problems: Hallucinations, Paranoia and Dementia (in very extreme cases!)

Communication problems: Difficulty forming and understanding speech.

And finally, heart problems.

image of alarm clock being held by an arm outstretched from a hole to show morning routine

Why do we need 8 hours sleep?

As we have discovered, reaching sleep deprivation can be extremely harmful. This is why it’s so important to aim for 8 hours of sleep every night. Sleep is essential for optimum body and brain function. A good night’s sleep can help you make better decisions, be more creative, maintain a healthy weight, and improve memory and learning abilities.

REM sleep is an integral part of our sleep cycle. REM sleep is characterised by heightened brain activity and is the state when dreams are at their most intense. This kind of sleep provides energy to the brain, so without it, you interfere with your long-term memory and your cognitive skills.

What’s the longest someone has gone without sleep?

World record holders:


  • Randy Gardner
  • 264 hours (11 days)
  • 17-year-old Randy Gardner stayed awake for 11 days in 1965, solely to win a school science fair


  • Tom Rounds
  • 260 hours (almost 11 days)
  • As a radio station publicity stunt, Tom Rounds managed to stay awake for close to 11 days in 1959


  • Peter Tripp
  • 201 hours (8 days)
  • Also in 1959, DJ Peter Tripp managed just over 8 days as part of a charity ‘wake-a-thon’

How to get an adequate amount of sleep

We understand how frustrating it is when our sleep doesn’t match our needs. And as we have seen, the effects are not desired. Try these tips to gain a better sleeping schedule, take control of your sleep, and enjoy day-to-day life without the overwhelming feeling of sleep deprivation.

  • Stick to a routine. Go to bed and wake up at the same time each day.
  • Avoid stimulants. Try not to consume alcohol or caffeine within 4 to 6 hours before bed.
  • Try meditation or yoga before bedtime.

We hope you found this helpful and if continue to struggle to sleep, contact your GP for help.

How long can you go without sleep? Infographic

How long can you go without sleep

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