Did you sleep well last night?


“Late night binge-watching or late night studying?” Well, we all have had this kind of question from our mothers when our eyes say we didn’t get enough sleep. Do you want to know the biology of sleep? Let’s dig deeper!

Stages of Sleep 

Non-REM Sleep


Non-REM sleep as the name indicates is the earlier stage of sleep. No eye movement happens during this stage of sleep. This sleep is somewhat lighter and is mainly responsible for the repair of our body, immune system maintenance, refreshing our brain, building muscles etc.

REM Sleep

REM stands for rapid eye movement sleep. This sleep is termed so because the rapid horizontal movement of the eyes is seen during this stage of sleep.

REM sleep is also called paradoxical sleep. This is the later part of the sleep where our brain experiences illogical vivid hallucinations that we call dreams. This sleep is called paradoxical sleep because during REM sleep the brain paralyses a lot of voluntary muscle groups so that the sleeping brain can dream without any disturbances. Imagine you dreaming of skydiving and acting out the dream. Hence this mechanism ensures that a lot of species members don’t pop out of the gene pool every time they have a dream. Interestingly during REM sleep, we see some parts become even more active than they are when we are awake.

Cerebral Cortex Human Brain Sleep


Mendeleev discovered the periodic table while dreaming.

While we are dreaming, the prefrontal cortex of our brain shuts off. The prefrontal cortex is responsible for logical thinking, hence dreams are usually very vivid and don’t make much logical sense. However, dreams happen during REM sleep and can lead to great creative awakenings too. Freudian Psychologists even ask their patients to write down their dreams as soon as they wake up because dreams provide a gateway to our unconscious mind.

Pop Culture and Politics

What’s common between The Rock, Ronald Reagan and Margaret Thatcher? They are famous for publicly speaking about how little sleep they often get. The main idea is to portray a symbol of power, struggle, hustle and strength. Political leaders and successful business people usually use this tool to win the hearts of people. 

Thatcher and Reagan, brilliant political leaders in the history of the United States of America and the United Kingdom respectively, both ended up getting Alzheimer’s disease.

Recent studies suggest that lack of sleeping is one of the fundamental factors in deciding if you will suffer from Alzheimer’s Disease in the future.

Ronald Reagan Margaret Thatcher

Ronald Reagan (left-hand side) and Margaret Thatcher (right-hand side) Image Source: britannica.com

The Rock Tom Ford

The Rock (left-hand side) Tom Ford (right-hand side)              

Sports Performance and Sleep

Sleep is essential for sports performance. Sleeping is the most viable legal performance-enhancing drug that most people are ignoring. A good night’s sleep not only helps to enhance stamina and give more energy while training but also helps to avoid injuries as well. Sleeping helps register better motor pathways to help learn the movement patterns.

Scientific research shows that certain sports statistics like vertical jump height or running speed greatly improved when athletes slept well.


 Roger Federer Courtney Dauwalter

Roger Federer is one of the greatest tennis players of all time. Certainly one of the most graceful with exceptional technique and 20 singles grand slam titles. He has won 8 Wimbledon Grand Slam Titles and his career that started in 1998 is still ongoing for two decades. He is one of the oldest players to win a grand slam title at the age of 36.

Roger Federer claims he sleeps 12 hours a day. 10 hours in the night and 2 hours nap in the afternoon. Sleeping has certainly helped him take his tennis game to the next level.

Courtney Dauwalter is a professional ultra marathon runner. She ran the Moab 240 which spans over 240 miles over the Moab Mountains. She completed the whole race with just 1 minute of sleep. She claims while she was running she had incredible hallucinations and was seeing rabbits talking to her, she saw mystical beings etc. Is that healthy or just weird? 

Motor Skills and Sleep

Sleeping is critical not only for performance but also for motor skill learning. Our wakeful brain learns the basic skills however automaticity of skills is done by sleeping. Remember when you first started learning how to drive and it was so difficult to understand how the car mechanics works. When do we have to put in the first gear, when the second gear and so on? However, you reach automaticity after some point and driving become flawless. This is because sleeping has made driving motor pathways automated in your brain.

Health and Wellness 

According to WHO any form of night time shift job is carcinogenic. This is because of all the scientific studies that have come forward linking lack of sleep to various cancer diseases.

    • Sleep is the foundational pillar of health. It is not besides diet and exercise but the foundation on which a healthy balanced diet and exercise lie upon.
    • Drowsy driving leads to more road accidents than drunk driving.
    • Mother nature has never in history encountered such a problem that a species voluntarily deprives itself of its sleep. Hence demonstrable diseases and sickness happen because mother nature never had to evolve in such a way to have a safety net against lack of sleep.
    • Cancer-fighting immune cells show a 70% decrease if sleep is less than 7-9 hours.
    • Sleeping is one of the key factors in determining if you will develop Alzheimer’s disease.
    • Men who sleep 6 hours have decreased testosterone levels which is the same as a man who is ten years older than him.
    • Lack of sleep predicts an increase in all-cause mortality
  • Sleeping for 7-9 hours is a must. 

Alcohol and Sleep

Alcohol certainly is not helpful when it comes to sleep. When Alcohol is in the bloodstream it sedates the cortex and so a drowsy feeling is experienced. However, sedation is not sleep. Alcohol blocks dream sleep and does not let the sleeping brain have dreams. 

This is why when individuals come off alcohol they tend to experience very strange dreams. This is obviously because alcohol has been blocking dream sleep for so long that the need for dreaming becomes so high it starts spilling into wakefulness.

Tips to improve Sleep

The Covid-19 pandemic and all the lockdowns have certainly not helped in this regard. Lack of inactivity has not only led to poor health but also distorted sleeping patterns. Many people have disoriented their circadian rhythms and hence sleep is suffering. Some tips to improve the same are as following:

  • Don’t eat close to bedtime. All the energy of the body will be used to digest the food and not on repairing the body and refreshing the conscious brain. 
  • Avoid screen usage 2-3 hours before going to bed ideally.
  • One hour of book reading is much better than one hour of iPad browsing.
  • Caffeine has a half-life of 6 hours and a quarter-life of 12 hours. So ideally drink coffee 6 hours before your bedtime.
  • Your bedtime and waking up time should be fixed no matter if it’s weekdays or weekends.
  • Exercise and stress your muscles for better sleeping patterns.
  • Avoid unhealthy sugar-rich food.
  • Make sure the room is completely dark and no light can seep through.
  • Ideally, the room temperature should be decreased because it helps us in sleeping quicker since our body has to reduce the body temperature by 2-3 degrees celsius to fall asleep.
  • A hot bath before bed can certainly help because it helps take away the body heat to the limbs and hence the body can fall asleep faster.
  • Melatonin levels can be maintained by going out in the sun so that when in dark your body knows it has to fall asleep now.
  • Sleep apnea is a common problem in adults and old age people. Consult a medical health professional if you face issues with your sleep.

If sleep does not serve a vital function, it is the biggest mistake of the evolutionary process ever made – Matthew Walker, PhD 

To summarize, simply because, when we are sleeping, we are taking away the time for hunting for food,  for finding any mates and also we are vulnerable to attack by predators. Therefore sleep is fundamental to us and that fundamentality is ensured by the evolutionary process.

Why do we think sleeping emerged from wakefulness? Maybe it’s the other way around. If you’re reading this late-night, go take a nap, honey!

Keep reading at MBD to quench your curiosity for such questions. 

Team MBD


Sleeping is your superpower by Matthew Walker, PhD- Sleep is your superpower | Matt Walker – YouTube

Read more about Matthew P. Walker | UC Psych (berkeley.edu)

More curious questions: Do Giraffes have a bluish-purple tongue? – My Biology Dictionary

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