is 4 hours of sleep ok for one night?
Better Sleep

How To Function on 4 Hours of Sleep

Last Updated on February 15, 2024 by Louise Carter

The body needs 7-9 hours of sleep to feel well-rested and refreshed upon waking. Despite this, many public figures and famous people claim to sleep just half this time and flourish.

You’re unlikely to feel energized after 4 hours of sleep, especially over a prolonged timeframe.

People don’t get enough sleep for various reasons, including working long hours, insomnia, being kept awake by roommates, barking dogs, crying babies, and snoring partners.

If you only sleep for 4 hours, wake up at the usual time to avoid interrupting a new sleep cycle. Take a cold shower, have a cup of coffee, and plan a realistic schedule for the day ahead.

Can You Survive on 4 Hours of Sleep?

We can survive with 4 hours of sleep, but surviving isn’t the same as thriving.

We should get about 8 hours of sleep because sufficient rest enables the body to complete sufficient sleep cycles to function at capacity in the morning.

A sleep cycle is broken into 4 stages, lasting around 90-120 minutes. If we sleep for 8 hours, we’ll enjoy 4-5 complete sleep cycles. Halve the time in bed, and you’ll halve the number of sleep cycles.

The adverse effects of only getting 4 hours of sleep include:

  • Feeling low, anxious, and irritable.
  • Elevated heart rate.
  • Difficulty concentrating and ‘brain fog.’
  • Hallucinations.

The human body is pretty adaptable, but there are limits to what it can tolerate, especially concerning long-term sleep deprivation.

The journal Sleep published a study that found that regularly getting just 4 hours of sleep ages brain function by about 8 years.

Is getting just 4 hours of sleep dangerous? If you make it your new routine, yes. You’ll get away with it for 1-2 days, but the risk of heart attacks and stroke will be elevated in the longer term.

Practice sleep hygiene and build up to 8 hours of sleep. Few people can flourish on less sleep. A strong correlation exists between prolonged inadequate sleep and dementia (Alzheimer’s disease).

Is No Sleep Better Than 4 Hours of Sleep?

If you’re particularly late to bed one evening, you may wonder if it’s worth getting some shut-eye, leaving you to decide whether to pull an all-nighter vs. 4 hours of sleep.

In truth, it’s always better to get some sleep, even if it is just 4 hours.

If you’re staring at the clock at 3 AM, knowing your alarm is set for 7 AM, it’s still better to get some rest. You may still be exhausted in the morning, but you’ll have some ability to function.

As explained by Occupational and Environmental Medicine, failing to sleep for 24 hours impairs brain function as much as alcohol intoxication.

You’ll operate at the equivalent of a blood alcohol level of 0.10%, which is high enough to get you a DUI.

is 4 hours of sleep enough to function?

How To Get Through The Day on 4 Hours of Sleep

If you’ve had a bad night’s sleep, it’s tempting to cancel your plans and stay in bed, but that’s seldom an option. You’ll likely need to get up and tackle your responsibilities for the next several hours.

After 4 hours of sleep the night before, you may consider a nap during the day. A nap for 15-20 minutes may sharpen you up. If you enter a deeper sleep, you’ll throw your sleep schedule further off-kilter.

Here are some techniques to make it through a day after a night of just 4 hours of sleep:

Wake Up on Time

If you haven’t slept well the night before, you’ll instinctively reach for the snooze button when your morning alarm sounds. An extra 10 minutes in bed can affect your energy levels, but not how you expect.

If you hit snooze and fall asleep again, you’ll recommence a new sleep cycle. This means you’ll be wrenched from a deeper sleep when the alarm sounds again.

This will make you even groggier than if you just got up in the first place.

If you need extra sleep, consider setting your alarm for 30 minutes later than usual. However, don’t expect miracles because you won’t feel the same as if you’d slept for 8 hours.

Cold Shower

Understanding how to wake up after 4 hours of sleep is essential, as you’ll be tired. Starting the day with a colder shower is an effective way to spark yourself into life.

Medical Hypotheses stated that showering for 2-3 minutes at temperatures of 20°F is used as a treatment for depression. Think of a cold shower as a mild, humane electroshock therapy.

The cold water increases beta-endorphin and noradrenaline in the blood, activating a range of electrical impulses in the brain. You’ll feel energized and content, at least in the short term.


Before starting the day, exercise is another way to recover from 4 hours of sleep.

Like a cold shower, this will flood the body with endorphins and set you up for a day. Of course, there are caveats to exercising after poor sleep.

If you only completed 2 sleep cycles, your muscles didn’t repair as they ordinarily would overnight. You shouldn’t attempt intense cardio or anything that strains the muscles, like weightlifting.

If it’s an option, walk to work instead of driving. If not, take a brisk stroll around the block or a light jog for 20 minutes. The key is to elevate the heart rate and release endorphins without risking injury.

Some Caffeine

For many, caffeine is a non-negotiable in the morning. If you only slept 4 hours, it becomes even more critical. Limit caffeine intake, and don’t assume drinking 2-3 cups of coffee instead of 1 will help.

Consuming too much caffeine has unwanted side effects. You’ll be jittery and irritable and likely need the bathroom regularly because caffeine is a diuretic.

Too much caffeine also makes you sleepy. Coffee and energy drinks block messages from adenosine, an inhibitory neurotransmitter that makes us feel tired. This is why caffeine makes us alert in the short term.

Adenosine can only be suppressed so much. If you consume too much caffeine, the brain will become flooded with adenosine. That extra cup of coffee will leave you exhausted and needing a nap.

Set Realistic Targets for the Day

Think realistically about what you can achieve after 4 hours of sleep. Don’t force yourself to tackle the day as though you slept normally. Your reflexes will be sluggish, and your decision-making will be impaired.

Rewrite your to-do list for the day for work or errands, and only tackle safe and achievable tasks.

Prioritize Duties

If you’re at work, you won’t be able to postpone all duties for 24 hours. While reviewing your list of tasks, tackle anything ominous or challenging first.

Procrastinating is tempting, but you’ll only grow more tired as the day progresses. Get the physically and mentally strenuous tasks out of the way first.

Eat Light And Avoid Sugar

You’ll probably be hungry after a poor night’s sleep but resist eating comfort food. A plate of carbohydrate-laden foods won’t energize you. You’ll feel even more sluggish.

Avoid sugar if you slept poorly. At first, the idea of a so-called “sugar rush” may be appealing – it’ll give you the energy to get through an important task. You’ll experience a mid-afternoon energy crash.

If you only slept for 4 hours the night before, eat light, little, and often the following day. Give the digestive system as little to do as possible while keeping your energy levels up.

can i operate on 4 hours of sleep?

Stay Hydrated

The Journal of the American College of Nutrition stated that cognitive performance is impaired by dehydration, and you’ll be working from a lower base in the first place.

As discussed, too much caffeine makes you sleepy. Exchange coffee or energy drinks for bottled water as the day wears on. You may be surprised at how much sharper this makes you feel.

Fresh Air

Take 1-2 minutes to step outside into the fresh air. This is invigorating for a tired body, allowing the body to synthesize vitamin D3 and enjoy a change of scenery that’ll restimulate the body and mind.

Regular Bedtime

You’ll accrue sleep debt if you fail to sleep longer than 4 hours a night. According to Scientific Reports, it can take as long as 4 days to repay 1 hour of sleep debt.

Don’t force the body to compensate for the sleep you lost the next night. If you slept for 4 hours on Monday night, don’t try to rest for 12 hours on Tuesday, expecting this to compensate.

If you don’t sleep enough on 1 night and sleep too much the next, your sleep rhythms will remain off-kilter. Ensure the mind and body are prepared to sleep 8 hours, making it unlikely to happen again.

We all have bad nights of sleep occasionally, and there will be times when you need to function on just 4 hours of sleep. However, making this your new routine is inadvisable.