How Long Can You Go Without Sleep?

Deadlines, hectic lifestyle, side hustles, watching sheep videos, mental disturbances, staying awake all night, insomnia—well, there are various reasons humans aren’t sleeping. But this brings to a very common question—how long can you go without sleep? Like literally?

Honestly, that’s a very tricky question and the answer to this is often 264 hours (which is about 11 days). Just in case you are wondering who actually went without sleep for so long, then it’s a person named Randy Gardner. Back in December 1963 to January 1964, Gardner went without sleep for 11 days + 25 minutes (which is 264.4 hours), a record-breaking documented moment to the previous one, which was at 260 hours by Honolulu DJ.

how long can you go without sleep

In 1964, Gardner was a 17-year-old high school student who decided to test his body & mind limits by going without sleep for as long as he could. This was for a science experiment at his high school.

However, this feat is not recommended for all. Even if someone manages to stay awake for days together, it’s not good for their mental health. So let’s understand in detail as to what can happen if someone had to go without sleep for days.

Sleeplessness Timeline: What Happens If You Go Without Sleep?

Sleep requirements differ from one person to the other and even depends on an individual’s age. Say, for instance, infants need two times the quantity of sleep than adults.

The CDC (Centers for Disease Control and Prevention) recommends adults between the age groups 18 and 60 to get a minimum of 7-8 hours of sleep every night. However, about 35% of the adults in the U.S. don’t get adequate sleep. This also means that an adult must stay awake for not more than 17 hours.

Going without sleep

Related: Do you want to understand sleep patterns? Here is the simple version of it.

Interestingly, within 24 hours of sleep deprivation, one will begin to experience its adverse effects. On that note, let’s understand those effects better, based on the number of hours.

1. Going without sleep for 24 hours

Most people will experience the effects of sleep deprivation after 24 hours. According to the CDC, remaining awake for 24 hours is often comparable to possessing a BAC (Blood Alcohol Content) of 0.10%. If you consider a place like the U.S., driving your car with a 0.08% of BAC or above is illegal.

Going without sleep for 24 hours will have these effects on the body:

  • Irritability
  • Drowsiness
  • Muscle tension
  • Reduced focus
  • Impaired judgment
  • Difficulties in coordination
  • Short-term memory issues
  • Elevated stress levels
  • Inclined blood sugar levels

Most of these effects happen because the brain conserves energy once it enters the phase of “local sleep,” wherein the body shuts down the neurons temporarily in a few regions but not all.

An individual entering local sleep might appear to be fully awake, however, their capability to perform any complex tasks begin to decline significantly.

2. Going without sleep for 48 hours

The sleep deprivation effects will intensify if the person remains awake for more time. So, considering the 48-hour of no sleep scenario, this is what will happen to the body:

  • Extreme fatigue or tiredness
  • Cognitive performance worsens
  • High stress levels
  • Low immunity levels

At this phase, the brain enters brief sessions of complete unconsciousness, which is often termed as microsleep. Now, microsleep happens involuntarily and may last for even a few seconds.

3. Going without sleep for 72 hours

After 72 hours of no sleep, the deprivation symptoms will intensify further. Fatigue or tiredness increases to a level where one finds it hard to focus or do something. It has profound effects on the person’s cognition and mood.

These are effects that a body goes through if you stay awake for 3 days (72 hours):

  • Paranoia
  • Extreme fatigue
  • Depressed mood
  • Difficulty multitasking
  • Difficulties in communicating
  • Severe memory & concentration issues

Interestingly, in this 2015 study, 2 astronauts experienced elevated heart rate, impaired cognitive functioning, and reduced positive emotions when they stayed awake for 3 days.

Do you know about Fatal Familial Insomnia? It is a rare and genetic sleep disorder which affects the thalamus and does not allow the affected person to sleep. The symptoms are usually mild to begin with like sleeplessness but gradually culminates into coma and finally death due to the lack of mental and physical rest that this disease devoid the body of.

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How Much Sleep a Person Needs to be Healthy?

As said earlier, sleep requirements differ from one person to the other and depend mostly on the age. According to the CDC, here’s how much a person should sleep:

Age groupSleep per day (recommended)
0 to 3 months old14 to 17 hours
4 to 12 months old12 – 16 hours (includes naps)
1 to 2 years old11 – 14 hours (includes naps)
3 to 5 years old11 – 14 hours (includes naps)
6 to 12 years old9 – 12 hours
13 to 18 years old8 – 10 hours
18 to 60 years old7 – 7+ hours
61 to 64 years old7 – 9 hours
65 years or older7 – 8 hours

General Tips for Good Sleep Hygiene

They say that “Quality matters as much as quantity” and this is so true when we talk about having a good night sleep.

Practicing a healthy sleep hygiene promotes better sleep quality and this requires taking a few steps, which include:

  • Keep the bedroom comfortable, cozy, and dark. Ensure that the temperature is cool.
  • Avoid taking stimulants like nicotine and caffeine before bedtime.
  • Maintain consistency with your sleep schedule. Sleep and get up on time every day.
  • Stay away from electronic devices like computers, laptops, televisions, and smartphones.
  • Relax before your bedtime. Perhaps, have a warm water bath, read a good book, or do some relaxation exercises.
  • Do not eat before your bedtime. Have it at least a few hours before.
  • Limit your naps in the daytime by just 20 minutes.

Wrapping Things Up

Sleep deprivation can occur when an individual doesn’t get adequate sleep. It isn’t clear how many hours a human can go without sleep. However, if the popular experiment of 1963 has to be considered, a person can manage to be awake for 11 days (264 hours).

Though missing 1 – 2 hours of sleep might not be a big deal, it can affect an individual’s energy levels, mood, and the ability to deal complex tasks negatively.

On the other hand, chronic sleep deprivation increases the risk of heart diseases, diabetes, and obesity. Most adults will need about 7-8 hours of sound sleep every night. So, make sure you get that!

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