Much is said in recent times about stress , a phenomenon known as “the epidemic of the 21st century”. The pace of life we lead, the socioeconomic situation and the working conditions to which we are subjected contribute significantly to the emergence of this condition.

Cortisol is one of the hormones associated with stress along with adrenaline, and its main function is to prepare the body for the moments of greatest activation when it is necessary to be alert. Stress is an adaptive response that prepares our body to carry out a fight or flight response to a dangerous or threatening stimulus. However, when this phenomenon occurs daily and becomes chronic, pathological stress appears causing serious problems for physical and mental health.

What is cortisol

Cortisol, also known as hydrocortisone, is a glucocorticoid . It is produced above the kidneys, in an area known as the adrenal cortex, in response to stress (physical or emotional), and its synthesis and release is controlled by the adrenocorticotropic hormone (ACTH) and its circadian rhythm.

In the morning, the amount of cortisol rises until it reaches its peak around 8:00 am (taking into account a standardized sleep schedule), because of the need to generate energy sources after a long night. In the afternoon it also increases to keep us active, but then it decreases progressively.

Stress hormones: cortisol and adrenaline

Cortisol and adrenaline are two hormones related to stress but have different functions. Understanding the function of each of these chemicals can help us understand what happens in our body when we are faced with a stressful stimulus. Reacting to stress is an instinctive behavior that has allowed humans to survive and develop, since our bodies are programmed to act in emergency or dangerous situations.

However, what has worked so well for us throughout history creates serious problems today because of the way we humans live. Furthermore, this phenomenon does not only occur in the face of physical stimuli, but our thoughts can also cause stress (for example, when a person suffers a post-traumatic stress situation and constantly relives a stressful situation from the past), which can lead us to a situation of excessive physical and mental wear and tear .

How Adrenaline Works

When faced with a stressful stimulus, adrenaline gives us a quick boost , so that our energy increases and we can escape from danger. Breathing, pulse and heart rate are accelerated so that the muscles respond more quickly. Pupils dilate, blood circulates faster and moves away from the digestive system to prevent vomiting. In general, the whole body prepares itself to react quickly to certain stimuli, so that it does not act at too slow a pace.

These physiological functions of adrenaline are complemented by other psychological functions such as keeping us alert and being more sensitive to any stimulus. Adrenaline, besides being a hormone, is also a neurotransmitter that acts in the brain. In this way, an intense dialogue is established between the nervous system and the rest of the body, which is very useful when processes that affect many areas of the body have to be triggered in a short time.

What function does it have in alarm situations?

In situations of stress, the cortisol level also increases. Its main functions are to increase the amount of sugar in the blood , and also to suppress the immune system to save energy and help the metabolism of fats, proteins and carbohydrates. This can be very appropriate for a specific moment, but not when the stressful situation is part of our daily life.

The release of blood sugar has the function of maintaining an appropriate energy level to respond effectively to the stress situation and allows us to be alert. Actually, it is the brain’s adrenaline that sends the signal for glucose to be released into the bloodstream (known as blood sugar), but cortisol contributes to its synthesis. It also contributes to the use of fats and proteins as energy substrates.

As we have seen, another response of cortisol to a stressful situation is that inhibits the immune system , because all the energy is needed to control the stress. In addition, this hormone also causes an increase in histamine, which explains why people tend to get sicker or suffer from herpes or allergies when they suffer from this phenomenon.

Relationship to stress

The excess cortisol that results from staying in stressful situations for a long time causes certain imbalances due to the energy drain we are experiencing . Some of the symptoms we may suffer are the following:

  • Feeling of fatigue, tiredness and exhaustion.
  • Problems with memory, concentration and learning.
  • Predominance of irritability, anger and aggression.
  • Physical pain (e.g., head or stomach)
  • Weakening of the immune system and therefore diseases, allergies, etc.

When stress manifests itself over a long period of time, then it is possible to experience complex patterns of anxiety, feelings of failure, insomnia or depression.

Other consequences of this hormone excess

Although cortisol has a bad reputation because it is associated with something as negative as chronic stress or burnout, in the human body it performs many vital functions. Among other things, it allows our rhythms to adapt to the pace that certain situations demand of us, such as times when our physical integrity may be at risk or when a test that we must overcome is approaching. Although the sensation may not always be pleasant, that does not mean it is not necessary or practical.

However, in the long term it causes a number of undesirable effects. For example, the production of cortisol, either in deficit or in excess, can interfere with the production of thyroid hormones and the conversion of these from T4 to T3.

Cortisol disrupts the reproductive system, causing infertility or even miscarriage when cortisol levels are too high or chronically high. In addition, the chronic increase in cortisol can cause intense hunger and food cravings due to the metabolic disorder that occurs, and also influences mental blocks and memory problems related to the feeling of “going blank”.


Cortisol is a stress-related hormone that itself is not negative . However, when stress becomes chronic and pathological it can create a number of problems or negative consequences for the person. Among these consequences, the following stand out:

  • Lowering of defenses
  • Stomach problems, diarrhea or constipation
  • Appetite problems
  • Mood swings
  • Difficulties concentrating and memory problems
  • Fatigue and tiredness
  • Headaches
  • Hypertension
  • Infertility and menstrual cycle interruption

If you are going through a stressful situation and want to know what you should do, in this article: “10 essential tips to reduce stress” you can find some keys to combat it.