Tuesday, October 3, 2023

14 signs of sleep deprivation that you may miss

Certain physical, emotional and mental signs indicate a lack of proper sleep. They may not be medical problems.

Executive Summary

Certain physical, emotional, and mental signs may indicate sleep deprivation, instead of an underlying medical problem. An extended sleep for 2–5 days may be enough to ‘cure’ you of those signs.

Physical signs are constant sickness, poor motor skills, dozing ‘at wheel’, poor eye control, skin damage, weight damage, and low libido.

Emotional signs are moody and impulsive behaviour, and depressive feelings.

Mental signs are cravings for junk food 🙁 , lack of concentration, forgetfulness, and poor decision–making.

Scientists think sleeping helps flush out toxins from our brains, cleaning up our nervous system.

The article explains more details on each of these points.

Science has not figured out any substitute for sleep yet. And, there are serious medical consequences of having inadequate sleep.

An obvious sign of getting inadequate sleep is excessive daytime sleepiness.

Read, on this website, an article: Are you suffering from excessive daytime sleepiness?

However, there are some more signs of sleep deprivation that you may not know about, or fail to catch. Keep an eye for them.

Less known signs of lack of sleep

Some signs are mental, a few others emotional, and some will be clearly physical.

Physical Signs

Constant sickness

Lack of sleep weakens your immune system, making you constantly sick. Our immune system produces cytokines during sleep, which protects us against infections. Lesser the sleep, higher the risk of catching infections.

In a study published in the journal JAMA Internal Medicine, after 14 days, those who slept for less than 7 hours a day were three times likely to catch common cold than those who slept for more than 8 hours a day.

Poor motor skills

Overall coordination of muscles reduces. Operating a complicated equipment or a vehicle becomes difficult and risky.

Micro–sleep, at the wheel

If you are driving long distances, on a monotonous journey, you may fall asleep for a few seconds at the wheel. This micro–sleep may be enough to cause accidents. This is called drowsy driving.

Poor eye control

Reading a book might become difficult. There are ciliary muscles around our eyes, which help them focus properly. With a lack of sleep, they are unable to focus properly.

Skin damage

Lack of sleep can give puffy eyes.

At night, our body repairs the damage to our skin. With lack of sleep, hormonal balance in the body goes haywire and skin repair gets hampered. Expect a dull–looking skin in the short–term.

Our bodies produce collagen during sleep. This collagen offers firmness to the skin. If you are sleep deprived for many days, the low production of collagen may cause wrinkles. Also, lack of sleep leads to release of stress hormone, cortisol. Cortisol breaks down collagen.

Our body secrets human growth hormone in the sleep, which thickens the skin. Less sleep, thinner and weaker the skin. Expect skin wrinkles in the long–term.

Weight gain

Lack of sleep affects hunger hormones in our body, increasing food cravings. But more on that later.

Without proper rest, our body slows down metabolism, which directly leads to weight gain.

Less sleep for a few days leads to rise in insulin resistance, causing elevated levels of blood insulin, which leads to excessive fat storage. A 2012 article published in the Annals of Internal Medicine showed a whopping 30% reduction in insulin sensitivity of fat cells, after just 4 days of sleeping for 4.5 hours a night.

Low libido

Men and women who lacked proper sleep reported decreased sex drive. Perhaps, the sleepiness and the lack of energy were the causes.

In half the men who did not sleep properly due to sleep apnea, testosterone secretions were found to be abnormally low during the night. This also could lead to low libido.

Emotional signs


If one sleeps poorly, one might get moody or grumpy. One may snap at others for small issues. People call it ‘having a shorter fuse’.

Impulsive behaviour

People with sleep deficit act more impulsively. Just as when under the influence of alcohol, they behave in an uninhibited manner, worrying less about the consequences.

Depressive feelings

Some people with a lack of sleep may start feeling depressed, or low, even after trivial difficulties. Some may get emotional and cry excessively.

Mental signs

Junk food cravings

Sleep deprivation causes the body’s hunger hormones to go haywire.

A sleep–deprived body produces more of ghrelin, the hunger hormone, making you crave food, especially the high–carbohydrate, high–fat (sugary, fatty) kind.

Low sleep levels also reduce the secretion of leptin, the satiety hormone. Thus, one continues to eat longer, as the brain does not signal to stop eating.

Incidentally, as I am writing this article, I have slept only 4–5 hours each for the last couple of days, working on these write–ups. And, though I eat very healthy food normally, right now, I am just madly craving something sugary or creamy.

Lack of concentration

Sleep–deprived people have reduced concentration. That affects assessing the situation correctly and making a proper judgement.

Impaired decision–making

With lack of sleep, decision–making ability reduces. Not only do the decisions become more error–prone, but also the person starts taking more time to decide.

Increased forgetfulness

The tired brain is not very attentive to things going on around. So, the formation of short–term memories from sensory memories becomes difficult.

Our brain stores short–term memories into long–term memories during its downtime, often during the sleep. However, with lack of sleep, the fatigued brain cannot form long–term memories well.

This completes our list of 14 less known signs of sleep deprivation. Here is my short video on these 14 signs:

And while we are at it, let me mention an interesting research reported by the National Institutes of Health about sleep.

Sleep flushes out toxins in the brain

The gap between brain cells increases during sleep, which, perhaps, helps the brain to clear out toxins that cause neurodegeneration. Of course, these findings were on mice.

In a way, lack of sleep prevents clean up of the brain and the nervous system. Since sleep helps flush out toxins, lack of sleep may increase neuro–degeneration.

We will await studies that try to check the effect of sleep on memory loss, Alzheimer’s and Parkinson’s, the main degenerative disorders of the brain.

What you can do

Actionable Tips

  1. If you are falling sick regularly, check if you are getting enough sleep.

    Do this, instead of starting a course of medicines for illness.

  2. Avoid operating any large machine or driving a vehicle when you have not slept well.

    Drowsy sleeping can lead to accidents.

  3. Try sleeping a bit longer, if you are noticing wrinkles.

    Sleep can thicken the skin, making it stronger.

  4. If you are following a weight loss program, make sure you get adequate sleep.

    Do this even if the program does not explicitly asks you to.

  5. If you notice moody, impulsive, or depressive behaviour, try sleeping a bit longer.

    Do this for 2 weeks and notice the difference, if any, before consulting a psychiatrist.

  6. Going into exam period, don’t let your sleep schedule go for a toss.

    You risk forgetfulness and lack of concentration, leading to poorer performance in the tests.

  7. If you crave junk food, check if you are getting enough sleep.

    It is not necessarily a problem of discipline.

  8. If you have to make any important or major decisions in the near future, ensure proper sleep.

    Else, you may end up making wrong decisions, or taking much longer time to come to decisions.

First published on: 22nd May, 2017
Last Update on: 27th May, 2021
Image credit: Nicole Berro on Pexels.com


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