Stress hormones

Definition of stress hormones

The term stress hormones includes all biochemical messengers of our body, which are involved in the physical stress reaction as a result of stress. The purpose of this reaction is to increase our performance in order to prepare us for an imminent fight or escape. Among the most important hormones involved in the stress reaction are the group of catecholamines and glucocorticoids.

The former is largely responsible for the reaction of our body within seconds and includes above all the hormones adrenaline and noradrenaline. They increase our heart rate and blood pressure and release energy reserves. With a little delay, the concentration of glucocorticoids, above all the probably best known stress hormone cortisol, also increases. Both large groups of the stress hormones are mainly produced in the adrenal gland.

What stress hormones are there?

The most important stress hormones can be assigned to two larger groups, the catecholamines and the glucocorticoids. The probably best known stress hormone cortisol belongs to the latter group and its effects in the body are very versatile. Besides its influence on the cardiovascular system, cortisol causes a release of energy reserves and a modulation of our electrolyte and water balance.

It also has an immunosuppressive and anti-inflammatory effect. An increase in cortisol is usually only noticed during prolonged stress. The catecholamines, on the other hand, play the main role in acute stress situations.

The most important representatives of this group are adrenalin, noradrenalin and dopamine. They cause a rapid increase in heart rate and blood pressure, increased sweating and increase our muscle tone. In addition to the above-mentioned main stress hormones, there are a number of other hormones such as prolactin and β endorphin, for which a level increase under stress can be observed.

However, their role in the stress reaction has not yet been clarified in detail. Cortisol is one of the most important hormones in our body. It belongs to the group of so-called glucocorticoids, which in turn belong to the group of steroid hormones.

The main function of cortisol is to mobilize energy reserves, regulate our immune system and increase our alertness. In addition, it causes our heart to beat faster, which results in an increase in blood pressure. All these functions are essential components of the physical response to prolonged stress.

The formation of cortisol is a highly regulated process that occurs via various signaling pathways. The hypothalamus, a region in the midbrain, secretes the hormone ACTH, which in turn acts on the pituitary gland. As a result, the pituitary gland releases the hormone CRH, which stimulates the adrenal cortex to produce cortisol.

The above-mentioned functions of cortisol are essential for our body to cope with stressful physical and mental situations. However, if the stress continues, over time the negative effects of cortisol will outweigh the negative effects of cortisol, which can result in states of exhaustion and dysregulation in our body. This topic might also be of interest to you:

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The hormone adrenaline belongs to the group of so-called catecholamines.

Other known hormones from this group are norepinephrine and dopamine. Adrenaline is mainly produced in the adrenal cortex and is released in dangerous situations, in cold and heat, physical work and psychological stress. In its function as a stress hormone, adrenaline exerts various effects in our body.

For example, it causes the heart to increase its ability to contract and a rapid heart rate. In addition, adrenaline constricts the vessels, which leads to increased blood pressure. It also causes an expansion of the airways.

In addition to mobilizing energy reserves, adrenaline inhibits bodily functions that would unnecessarily consume energy in a stressful situation, such as digestion. Even though thyroid hormones are generally not counted among the classic stress hormones, there is a large overlap between their effect and that of adrenaline or cortisol. However, their blood levels do not depend on the occurrence of stress situations.

As the name suggests, these hormones are produced in the thyroid gland. The most important representatives are tyroxine (T4) and triiodothyronine (T3).Although the latter is the much more active form of thyroid hormone, the thyroid gland produces 90% tyroxine. However, this is converted to the more effective T3 in the cells of the target organ.

The effect of the thyroid hormones is extremely diverse. For example, they basically increase physical activity, in the sense of an increase in heart and respiratory rate, cause an increased production of red blood cells and lead to an increased motility of the intestine. Although the exact mechanisms are not yet known in detail, many of the effects of thyroid hormones are due to an increase in the action of catecholamines. In addition to the above-mentioned functions, thyroid hormones also play a key role in the development of the body and its adaptation to environmental conditions.