How does lack of sleep affect the brain and cognitive performance?

Megan Smith
 min read

How does a lack of sleep affect the brain and cognitive performance? If you’ve had a rough, sleepless week, you’ll notice that you are unable to concentrate, less productive and more forgetful.

How does lack of sleep affect the brain and cognitive performance?How do you feel today? Did you sleep well? What a joy to wake up after a good night’s sleep!

You feel rested, serene, in a good mood and ready to start a new day!

But when you have a bad night, it’s a different story.

You feel weak, groggy, sensitive, irritable, and your intellectual abilities seem to be diminished.

Indeed, thinking about a project, performing a mental calculation or memorizing information seems much more difficult.

Sleep for the brain

Sleep therefore plays a major role in your mood, and in your mental capacities, known as cognitive skills.

The cognition gathers the whole of the mental processes like memory, language, reasoning, and learning.

In everyday life, you can’t always get as much sleep as you’d like.

Indeed, work, commuting between home and work,  children… all fight for your attention and make sleep the fifth wheel of the bus.

Sleep is vital and you should feel the need to sleep after a long day.

Your sleep is part of your brain’s functions and it is very important to sleep in order to live all your days to the fullest.

Quality sleep with also enhance your mental abilities.

Tip: Ensure your house guests also get quality sleep, even if it’s only for a few nights, by checking out our top portable beds guide.

How does lack of sleep affect the brain? Your brain needs energy to function properly

To understand how sleep is involved in your brain and cognitive abilities, we must first understand how your brain works.

Your body, that is to say all your cells (and by extension, body tissues), needs energy to function.

It is essential to eat and drink well to provide your body with all the elements that allow it produce energy, which is necessary for its proper functioning.

Your brain functions thanks to the activity of its neurons, which need to use stored energy.

As in all situations of energy production and use, your brain also produces waste.

To function, it will constantly produce and use energy and evacuate waste.

Related: Read our other article Mind-blowing facts about sleep you need to know for other interesting facts about sleep.

Is my brain sleeping?

When you fall asleep, you gradually fall into a state of unconsciousness.

When you stand still, your perception of the environment is greatly diminished. It would then be logical to imagine that your brain is also inactive during this rest period.

This is what scientists have long thought… But the reality is quite different!

The brain is active during the REM phase of sleep.

During this phase, you are totally immobile and might even feel paralyzed, but your brain is very active, in a state close to wakefulness.

This phase is also characterized by rapid movements of your eyes. Your brain is therefore as active as if you were awake and moving, whereas you are asleep and totally immobile.

This is why this stage is called REM (Rapid Eye Movement).

The brain is never completely at rest.

However, what seems indisputable is that the energy consumption of your brain changes during your sleep.

It slows down very strongly during your slow wave sleep (especially the deep stages), but is accelerated during REM sleep.

When you sleep, your brain is not totally inactive and certainly not in a passive state.

The functioning of the brain in sleep deprivation | How does lack of sleep affect the brain?

Sleep is essential to your brain function. However, you are almost certainly forced to sleep less than you would like on a regular basis.

Work, family, social constraints, time change, etc. all impact on the length and quality of our resting time.

This sleep debt can lead to drowsiness, a decrease in your attention span and memory capacity, mood disorders and a decrease in your efficiency and endurance at work.

How to explain this?

How does lack of sleep affect the brain? A decrease in intellectual capacity

Without full energy and without emptying toxins, you will almost certainly have difficulty performing intellectual (cognitive) tasks that will tax your brain.

Indeed, your brain (and a fortiori your body!) will set up a strategy of economy and will use the minimum of energy resources for each mental activity.

This explains why you feel like a robot on days when your nights have been short or your sleep has been severely disturbed.

Related: While not sleeping enough isn’t a good thing, sleeping too much brings its own set of problems, read more on Oversleeping: Health effects and risks of sleeping too much.

A brain in automatic mode

An economic brain forces you to use an automatic mode of operation that relies on the use of habits and cognitive skills.

Your brain’s frontal cortex, the area of the brain behind the forehead, plays a major role in your complex intellectual functions such as language, memory, and reasoning.

Experiments carried out on humans have shown that this part of the brain was less activated overall in sleep-deprived subjects compared to control subjects who had slept well.

Your brain needs enough time to perform the cleansing necessary for its proper functioning.

If you are sleep deprived, the accumulated waste will then hinder and slow down your brain.

You will have difficulty concentrating, working and remembering certain events because your brain has not had time to consolidate them while you sleep.

In this case, the feeling of not being effective is a very real feeling!

How does lack of sleep affect the brain and cognitive performance? Conclusion

Your brain is like a car that needs energy to run!

It is always active when you are asleep, just like your breathing.

During sleep, your brain will alternate between periods during which it will reduce its consumption, feed its energy reserves and cleanse the toxins accumulated during the day.

At times it will replay information and events encountered during the day in order to consolidate them and thus feed your memory bank, and build memories.

On the other hand, when you are deeply sleep deprived, your brain will not have had the time to take advantage of these two key sleep periods.

It will start to function in economy mode to preserve its energy resources.

You will be less effective because your cognitive functioning will be impaired.

Only one solution: rely on your skills and expertise! You won’t be faulted for being sleepy if you do well what you do best.

About Megan Smith

Megan has been fighting overweight and her plus size since her teenage years. After trying all types of remedies without success, she started doing her own research. Megan founded Plus Size Zeal to share her findings. She also developed various detailed buying guides for plus-size people in order to make their lives easier and more comfortable. Read More