What Does Your Brain Do While You Sleep?

When you're sleeping, your brain restores the energy it used during the day and processes new information. It's an extremely important process that improves your memory and learning skills. 
What Does Your Brain Do While You Sleep?

Last update: 13 May, 2020

Sleeping is both a fascinating and necessary process for all human beings. Due to the physiological and neuroanatomical information humans lacked in the past, this phenomenon has always been surrounded by mystery and speculation. However, nowadays, many available research studies explain what the brain does while we sleep.

A woman dreaming: what does the brain do while you sleep?

What happens in your brain while you sleep?

During a night’s rest, the brain goes through different stages of sleep with various levels of brain activity: four of these stages are non-REM and the fifth one is REM sleep.

  • During stage 1, you experience sleepiness, your muscles start to relax, and your brain activity slows down. However, this is a light sleep state, so you can easily wake up from it.
  • In stage 2, your body’s temperature, heart rate, and breathing start to decrease progressively.
  • During stages 3 and 4, you’re in a deeper sleep state and your brain activity keeps a very low frequency. At this point, it’s harder to wake up and it’s usually when parasomnia happens: night terrors or sleepwalking.
  • Then, there’s the REM stage, in which you experience rapid eye movement. Your muscle tone decreases drastically and your breathing and heart rate become irregular. It’s during this stage that you start to dream more vividly. If you wake up during this stage, you’ll most likely remember what you were dreaming of.

A complete sleep cycle lasts approximately 100 minutes; the first 60 to 70 minutes are spent in the first four stages. Finally, during a normal night’s sleep, you’ll complete between four and six cycles.

What does your brain do while you sleep?

Learning and memory

It’s been demonstrated that memory and retention get much better after a sleeping period than a similar awake-resting period. The positive effect is more prominent when it comes to declarative memory (which is related to facts and events) and procedural memory (related to abilities and motor skills).

Even short periods of sleep (6-minute long naps) can have a positive impact when it comes to information retention. The more you sleep, the better it is for your memory.

Another interesting fact is that the time between learning and sleep is highly relevant. Thus, if you want to consolidate certain information, sleeping after you study will help you a lot.

Energy conservation

Although this isn’t the main goal of sleep, it’s true that sleeping contributes to preserving or restoring the energy you used during your daily activities. Especially during stages 3 and 4, your metabolic rate decreases: your body gets colder and your heart rate and breathing become slower, you consume less oxygen, and you have less muscle tone. Furthermore, when your energy expense is high during the day, you tend to sleep more.


Sleep is essential to fight tiredness and to get your body to its original state. Studies show that an increase in sleep after a stressful time can make up for the brain’s mental burden. While physical fatigue disappears with rest, mental fatigue needs sleep, specifically.

A sleeping man.

Looking for solutions

You’ve probably heard the phrase: “I have to sleep on it”. That expression actually has some scientific truth to it; individuals who spend more time in the REM stage find more creative solutions.

Sleeping has a connection with creative and problem-solving abilities. When you sleep, your brain interprets information and combines ideas. Those weird dreams that make no sense to you are the way your brain processes, explores, and rehearses several different solutions to your real problems.

That’s why it’s essential to have great sleep quality. Your body, and especially your mind, need the time to restore, consolidate information, and find new perspectives and solutions. Caring about your sleep is caring about your brain.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Carrillo-Mora, P., Ramírez-Peris, J., & Magaña-Vázquez, K. (2013). Neurobiología del sueño y su importancia: antología para el estudiante universitario. Revista de la Facultad de Medicina UNAM56(4), 5-15.

  • Gala, F. J., Lupiani-Giménez, M., Guillén, C., Gómez-Sanabria, A., Lupiani-Cerdeira, N., & Roa, J. (2003). El sueño normal: perspectivas actuales. C Med Psicosom67(68), 7-19.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.