Last Updated on February 28, 2023 by Mike Robinson

What are stress hormones?

Cortisol is the primary stress hormone that changes your body and mind. After stress hormones like glucagon and prolactin, there are reproductive hormones like estrogen, progesterone, and testosterone, as well as hormones that affect growth.

Hormones are chemicals that send messages through your blood to your organs, skin, muscles, and other tissues. This helps your body’s different systems work together. Your body gets messages from these signals about what to do and when to do it. 

Any event or thought that makes you feel anxious, tense, or frustrated can generate stress, a feeling of physical or emotional strain.When someone is under stress, they not only go through psychological changes but also go through several bodily changes.

This article will explain how these physical changes occur and how stress hormones work.

What is stress?

Stress is a condition of tension and anxiety that leads to various changes and discomfort in the individual experiencing it. In 2000, Bruce McEwen defined stress as a real or imagined threat to an individual’s physiological or psychological integrity that results in a physical or behavioral response.

In medical terms, stress is a situation in which circulating levels of glucocorticoids and catecholamines rise. To understand the effects of stress, we must remember that our body experiences a lack of harmony in homeostasis when we experience prolonged stress.  Thus, homeostasis is an essential concept for understanding stress and its hormonal implication. This concept refers to the idea that the body has an ideal oxygen level in the blood and a preferred temperature range.

Homeostasis helps maintain optimal levels of these variables, allowing our bodies to function correctly. However, when a stressor appears, our body moves away from homeostatic balance, which can modify our body’s variables. So when we feel threatened, our body changes the homeostatic balance and increases blood supply, heart rate, muscle tension, or sweating. 

But this change does not constitute a state of stress. The human body knows what to do to respond to these situations.

Also Read: Progressive Muscle Relaxation: Practicing It in 12 Steps

If our body has more stressed muscles and a higher heart rate, we will be more prepared to perform a rapid behavioral response than if our body is relaxed.

The hypothalamus, stress, and the autonomic nervous system

The stress response has a lot to do with the autonomic nervous system. Thus, in stressful states, one part of this system is activated (the sympathetic nervous system ), and the other is inhibited (the parasympathetic nervous system).

The hypothalamus is similar to a control room. This part of the brain talks to the rest of the body through the autonomic nervous system, which controls things like breathing, blood pressure, and heart rate. It also regulates the widening or narrowing of crucial blood vessels and small airways in the lungs called bronchioles. 

The sympathetic nervous system and the parasympathetic nervous system are both a part of the autonomic nervous system. The sympathetic nervous system works like a car’s gas pedal. It sets off the fight-or-flight response, which gives the body a burst of energy so it can react to what it thinks are threats. The parasympathetic nervous system slows down the body’s movements. It triggers the “rest and digest” response, which calms the body down after the danger has passed.

The sympathetic nervous system activates when our brain senses an emergency (in cases of continuous stress). Its activation increases alertness, motivation, and general activation. Also, this system activates the adrenal glands of the spinal cord, which are responsible for releasing the stress hormones that we will discuss below.

The other half of the system, the parasympathetic nervous system, is inhibited. This system performs vegetative functions that promote the growth and storage of energy, so when the system is off, these functions are no longer operating.

Stress and hormonal changes

The main component of the stress response is the neuroendocrine system, especially the hypothalamic-pituitary-adrenal axis. In the face of stressful events (or events interpreted as stressors), the sympathetic nervous system is activated, which immediately starts the adrenal glands of the neuroendocrine system.

This activation stimulates the release of vasopressin in the hypothalamic-pituitary axis. These substances stimulate the pituitary to release another hormone, corticotropin, into the body.  Corticotropin then induces glucocorticoids, including cortisol, from the adrenal cortex.

Thus, the hypothalamic-pituitary-adrenal axis releases more glucocorticoids in response to stress. Therefore, cortisol is the principal stress hormone. Stress also alters glucagon, prolactin, and reproductive hormones like estrogen, progesterone, testosterone, and growth-related hormones.

The main stress hormones

 Cortisol

Cortisol is the quintessential stress hormone because the body manufactures it in emergencies to help us cope with problems and respond quickly and effectively. When we are stressed, the release of cortisol is triggered. In normal situations (without stress), the cells of our body use 90% of their energy in metabolic activities such as repair, renewal, or the formation of new cells.

However, as discussed earlier, in situations of stress, our brain sends messages to the adrenal glands, causing them to release larger amounts of cortisol. Cortisol releases glucose into the blood to send more energy to the muscles. After our stress level goes down, our body has no lingering adverse effects.

However, chronic stress causes cortisol levels to rise, which makes it difficult for the body to release glucose into the blood. This paralyzes the body’s natural processes for healing, regeneration, and the production of new tissues.

The first symptoms of having high cortisol levels for extended periods are no sense of humor, irritability, anger, permanent tiredness, headaches, palpitations, hypertension, lack of appetite, digestive problems, and muscular pains or cramps.

 Glucagon

Glucagon is a hormone produced by the pancreatic cells that affect how we metabolize carbs. Its primary purpose is to enable the liver to release stored glucose and restore the body’s supply when it gets low. Glucagon plays a different role than insulin. When blood glucose levels are too high, insulin lowers them; when blood glucose levels are too low, glucagon raises them.

 Prolactin

Prolactin is a hormone secreted by the anterior pituitary gland in the brain responsible for stimulating women’s milk secretion during lactation. Thus, when a woman is in the lactation period, she can produce milk by releasing estrogen. However, cases of high stress can cause hyperprolactinemia.

Hyperprolactinemia is an increase in prolactin in the blood that immediately slows the production of the hypothalamic hormone, which is responsible for synthesizing estrogens. Thus, by increasing prolactin levels, the hormone that synthesizes female sex hormones is blocked, causing a lack of ovulation, a decrease in estrogen, and consequent menstrual periods such as a lack of menstruation. Through prolactin, elevated stress levels can affect sexual functioning in women and alter the menstrual cycle.

 Sex hormones

Three sex hormones—estrogen, progesterone, and testosterone—also function differently under stress.

 Estrogens

Stress reduces the synthesis of estrogens, which can alter the sexual functioning of women. However, the relationship between estrogen and stress is bidirectional; that is, stress can reduce the creation of estrogens, but in turn, estrogens may constitute a hormone that protects against stress.

An experiment by Princeton University psychologist Tracey Shors using 44 rats demonstrated this fact. He checked the stress response between female rats without modification and female rats with extracted ovaries.

 Progesterone

Progesterone is an ovary hormone responsible for regulating women’s menstrual cycle. It also controls the effects of estrogens. Experiencing stress for long periods can decrease the production of this hormone. This causes a progesterone imbalance that can lead to reduced sex drive, excessive tiredness, weight gain, headaches, or mood swings.

 Testosterone

Testosterone is the male sex hormone that allows the growth of reproductive tissue in men. It also enables the development of secondary sexual characteristics such as facial and body hair or sexual erections. When a person suffers stress regularly, testosterone levels decrease as the body chooses to invert its energy into producing other hormones, such as cortisol.

Therefore, stress becomes one of the leading causes of sexual problems such as impotence, erectile dysfunction, or a lack of sexual desire. Also, lowering testosterone levels can produce other symptoms, such as frequent mood swings, constant fatigue, and the ability to sleep.

We can see how stress is closely linked to the hormonal functioning of our bodies. Being constantly subjected to stressful situations can lead to serious psychological and physiological health issues.