Get Your Sleep Right – The Effects of Lack of Sleep

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Sleep is not a luxury; it is a human need and is invaluable for your health. Actually, one of the oldest forms of torture is to prevent people from sleeping.

During sleep, our bodies do most of the repairing, construction, growth, detoxification, and cleansing processes. Some scientists consider sleep also a way to preserve energy.


This is not an article about how to improve your sleep, as we have already extensively addressed that subject in the e-book 25 Hacks to Get Your Sleep Back which you can download here. In this article, I’ll provide an extensive list – not intended to be exhaustive – of science-proven negative health consequences of lack of sleep.

The first step to providing a proper understanding of the subject is to mention that research has shown that we need 7 – 9 hours of uninterrupted sleep every night. When people get this optimal amount of uninterrupted sleep time, the different hormonal cascades will be properly regulated during the day.

As I mentioned before, this is a list, classified by the different systems/organs/functions affected, and most of them have been seen with just one night of sleep deprivation.

Hormonal alterations:

  • Leptin and Ghrelin dysregulation
  • Insulin and blood sugar dysregulation
  • Decreased insulin sensitivity
  • Decreased thyroid function
  • Increased cortisol secretion
  • Increased estrogen production
  • Decreased estrogens excretion
  • Decreased growth hormone production
  • Decreased DHEA production
  • Decreased testosterone production
  • Decreased melatonin production

The aforementioned alterations can lead to obesity, weight gain, diabetes, infertility, decreased sexual function, sugar and carbs cravings, and toxicity.

Cardiovascular dysfunction:

  • Dyslipidemia
  • Increased blood pressure
  • Arrhythmia
  • Elevated heart rate

All of the above can lead to an increase in the risk of heart disease.

Cancer risk:

  • Increase in the risk of breast cancer
  • Increase in the risk of colorectal cancer
  • Increase in the risk of hormonal driven cancers

It is my opinion that lack of sleep can increase the risk of developing all types of cancer

Brain function:

  • Impaired memory
  • Decreased memory formation
  • Decreased learning
  • Decreased cognition
  • Greater risk of depression
  • Greater risk of suicide
  • Central nervous system dysfunction

In essence, the brain cannot operate at its full potential if a lack of sleep is present


  • Increased oxidation and oxidative stress
  • Increased inflammation
  • Increased insulin
  • Increased cortisol

Yes, aging is considered a condition and the factors above can increase its rate of development.

Immune function:

Lack of sleep negatively alters the proper function of all the components of the immune system.

Sports performance:

  • Increased risk of overtraining
  • Increased risk of under-recovery
  • Decreased capacity for gaining muscle mass
  • Decreased capacity of gaining strength
  • Decreased performance in the sport

The human body cannot perform at its full potential if it is not entirely rested and recovered.

As you can see, lack of sleep is not a joke or just a game. It is extremely serious and can take a big toll on overall health. As coaches and trainers, we work hard to have our athletes/clients get the best possible results, and that’s why I devote a full lecture on sleep during the Metabolic Balance Class, in order to provide you with up-to-date information and strategies to address sleep in the best possible way.

Coach Carlos Castro