What happens to your body when you don’t get enough sleep?

There is no denying the importance of sleep as a good night’s sleep can set you up for a positive and productive day.

Sleep is one of the most important things we can do for our bodies, along with exercise and a fully balanced, nutritionally complete diet – it’s an integral part of making sure we stay healthy and happy.

And now Hormone specialist Dr Martin Kinsella has revealed how a lack of rest can affect the endocrine system in several ways.

He told FEMAIL, “The endocrine system is a system of glands that make the hormones that allow cells to talk to each other. They are responsible for virtually every cell, organ and function in the body.’

While a hormonal imbalance can be the cause of a lack of sleep, not sleeping can also cause hormones to become unbalanced.

Expert Dr Kinsella has revealed how a lack of rest can affect the endocrine system in several ways

Dr. Kinsella continued, “Studies have shown that people who sleep less than seven hours a day tend to gain more weight and are at greater risk of becoming obese than those who sleep seven hours.”

While one of two interrupted or shorter nights will leave you feeling tired, irritable and hungry, it is unlikely to lead to further problems.

But Dr Kinsella explained exactly what a lack of sleep over an extended period of time can lead to:


Dr. Kinsella explained that a lack of sleep causes cortisol levels to rise.

He said, “When you sleep, your cortisol levels go down with sleep, so when you don’t get enough sleep, your cortisol levels go up.”

The short-term health problems of insufficient sleep include:

  • Low mood
  • Tension
  • Hungry
  • Fatigue
  • Being cold
  • Finding it difficult to exercise and poor recovery after exercise
  • Decreased stress response
  • Low libido
  • Bad concentration

Long-term health problems caused by insufficient sleep include:

  • Mental health problems
  • Hair loss
  • Inflammation
  • Insulin resistance
  • Hormone imbalances such as lower testosterone, insulin resistance and so on.
  • Fertility problems
  • diabetes

Cortisol is the stress hormone and so chronic levels of elevated cortisol are very bad for the body and put the body in a catabolic state.


“Cortisol also breaks down muscle tissue, which causes the body to use the glucose and amino acids that make up your muscles,” explains Dr Kinsella.

Amino acids are the building blocks of muscle tissue, so it’s harder for the body to build muscle when they’re being broken down

We also use cortisol to reduce inflammation. When you have chronically elevated cortisol, you could be in an inflammatory state.


Think about how a night of poor sleep or too little sleep can leave you feeling lousy and irritable the next day.

The expert explained: ‘Elevated cortisol levels can have an effect on the brain, causing changes in neurotransmitters in the brain, which can create an imbalance in serotonin – your happy brain hormones.

“So you can get poor mental health,” says the hormone doctor.

Plus, it can work both ways: Sleep deprivation can affect your mood, and your mood can affect how much and how well you sleep.


Dr. Kinsella explained that when you get high levels of cortisol in the body, it can start to lower other anabolic hormones like your testosterone and DHEA levels.

Dehydroepiandrosterone (DHEA) is a hormone that your body produces naturally in the adrenal gland.

DHEA helps produce other hormones, including testosterone and estrogen.

Natural DHEA levels peak in early adulthood and then slowly decline as you age.

High levels of cortisol can throw the adrenal glands off balance and reduce the amount of topterone produced, lowering libido.


According to the expert, sleep deprivation also lowers leptin levels, which affects your appetite.

Leptin suppresses appetite and lets your body know when it’s time to stop eating, so when you’re sleep-deprived you tend to be more hungry.

Similarly, ghrelin, produced in the stomach, is another hormone affected by sleep, or the lack of it.

When leptin levels are lowered due to lack of sleep, ghrelin levels rise and this also makes you feel hungrier, as the function of the hormone is to tell the brain that you are hungry.


A lack of sleep can also affect the thyroid, causing an increase in TSH (thyroid-stimulating hormone, according to Dr. Kinsella), which slows metabolism and can cause an underactive thyroid.

With an underactive thyroid gland, your thyroid gland (a small gland in your neck) does not produce enough hormones.

Symptoms may include fatigue, feeling cold, hair loss, weight gain, and depression.

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