What is cortisol, known as the stress hormone?

What is cortisol, known as the stress hormone?

Definition and role of the stress hormone: What is cortisol and what does it do?

Cortisol is a hormone, namely a messenger secreted by a gland and which circulates in the body through blood for send messages to different organs. It is a so-called steroid hormone, which means that it is synthesized from cholesterol.

Dr. Lecornet-Sokol, endocrinologist: Cortisol is secreted by the adrenal glands, located above the kidneys, which have the particularity of producing several hormones that are important in various body functions, including stress-related hormones.

The adrenal glands are made up of two layers:

  • the outer layer called the adrenal cortex which secretes, among other things, cortisol,
  • and the inner layer called the adrenal medulla, which synthesizes theadrenaline and norepinephrine.

When these last two are the hormones of reactivity, synthesized first in the event of acute stress, the cortisol is not produced secondly in case of acute stress or for a prolonged period if the stress becomes chronic or if an anxiety persists.

Cortisol is the hormone of stress but also energy. It is secreted cyclically during the day: in large quantities in the morning when you wake up when you need energy – ancestrally for hunting, gathering, fishing – then less and less during the day and almost more at night. . “That’s what we call the nycthemeral rhythm of cortisol secretion“, summarizes the endocrinologist.

What are the effects of cortisol on the body?

The secretion of cortisol by the adrenals is done through a cascade of hormones.

  • It is first initiated by thehypothalamus who, in a situation of physical or psychological stress, secretes a hormone called CRH (Corticotropin-Releasing hormone).
  • In response, another gland located at the base of the brain and called pituitarywill in turn secrete a hormone called ACTH (adrenocorticotropic hormone), which causes cortisol release by acting on an adrenocortical receptor.

“It’s a feedback system since the system adapts according to the needs of the body: in the event of excess production of cortisol, ACTH will drop. In the event of significant stress: the CRH increases, it is the response to stress”, summarizes Dr. Lecornet-Sokol.

The main role of cortisol is to give us energy in peak stress situations, to allow us to flee, fight or fight.

“For this, cortisol has an action on the metabolism mainly of glucose, but also of fats“, details the endocrinologist. It thus stimulates the production of sugar by the liver, in order to provide immediate energy to the body, and increases the breakdown of lipids to make them available.

The chronic stress hormone also has an effect on calcium: it inhibits osteoblastic activity, which means thatit makes bone calcium available to run our cells. “It is also a catabolic function of using energy resources,” continues Dr. Lecornet-Sokol.

Other actions of cortisol:

  • it regulates muscle function and blood pressure, and increases alertness.
  • “Cortisol can finally have action on mood : a moderate excess improves mooda insufficient intake affects itand a large excess makes you nervous and irritated” sums up the specialist.

What is the normal cortisol level according to the daily cycle?

The secretion of cortisol, and therefore its level in our body, varies throughout the day, following the famous nycthemeral rhythm. the cortisol dosage must therefore be placed in a time context to be able to be analyzed correctly. “The laboratory standards displayed in the dosage report do not always take into account the sampling schedule” insists the endocrinologist. Having values ​​that are too high does not necessarily mean that you are making too much cortisol..

Normal theoretical values ​​are:

  • in the morning around 8 a.m.: between 275 and 685 nmol/l,
  • in the middle of the day around noon: between 190 and 468 nmol/l,
  • in the middle of the afternoon at 4 p.m.: between 165 and 300 nmol/l,
  • in the evening around 8 p.m.: between 110 and 250 nmol/L
  • and finally at night: between 55 and 190 nmol/l.

High cortisol: what can be the causes of an increase in cortisol?

There are physiological situations that cause an increase in blood cortisol, without there being any pathology of the adrenals.

  • The people who work at night, have a disturbed nycthemeral cycle because of their rhythm of life. They generally have too high cortisol levels during the day, which causes them sleep disorders.
  • the high stressgreat anxiety or depression, can cause large excesses of cortisol in the morning.
  • A alcohol consumption too important.
  • A coffee consumption too important.
  • the overweightor eating disorders such asanorexia mental.

It exists several ways to measure cortisol levels to check for adrenal dysfunction. “In general, when a cortisol deficiency is suspected, a blood test is performed in the morning, at the time of the peak of secretion”, explains Dr. Lecornet-Sokol. It is when we want to diagnose a possible excess of production that things are more delicate. “We should theoretically do an analysis in the evening or even at night, but the laboratories are closed” continues the specialist. Two examinations can then be offered:24 hour urine analysis where the minute brakingwhich consists of seeing whether or not it is possible to block the adrenals.

Blood test

The classic dosage of cortisol is done by blood sampling, carried out in the bend of the elbow by medical personnel. Most often, ACTH is measured at the same time as cortisol, in order to detect a possible dysfunction of the pituitary gland.
The patient must be rested at the time of sampling, stress and physical exertion should be avoided as much as possibleso as not to raise the level of cortisol.

24-hour urinary free cortisol how to do?

The measurement of urinary free cortisol makes it possible to detect hypersecretion of cortisol by the adrenal glands. For this assay, urine should be collected in a bottle provided for this purpose, over a period of 24 hours. The container must be kept cool between each collection. The results of the assay make it possible to evaluate the total quantity of cortisol produced during the day, and therefore to highlight a possible hypersecretion of cortisolcharacteristic of Cushing’s syndrome.

Except in the case of Cushing’s disease, characterized by hypersecretion of cortisol, there is no reason to lower cortisol levels.

Dr. Lecornet-Sokol: People often see the problem upside down, and think that it’s the excess cortisol that causes the stress, but it’s the other way around. Lowering your cortisol level does not therefore prevent a period of stress or chronic anxiety.

The question to ask is therefore rather: how to avoid secreting too much cortisol ? And the main solution is to manage stress. “There are many natural ways to reduce stress and anxiety : the meditationmindfulness, sport, including yoga, a balanced diet, psychotherapy, breathing, relaxation, hypnosissophrology or even activities related to nature” lists the endocrinologist.
On a daily basis, maintaining good social and family relations is also essential to be soothed and less stressed.
A healthy lifestylewith in particular a balanced diet, rich in whole foods and low in refined or hyper-processed foods, also helps to limit peaks in cortisol secretion.
Finally, take care of her sleepnot going to bed too late and having an average of 7 to 8 hours of sleep per night, is essential for a good regulation of your stress hormones.

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