One of the ills of the century has a name that many people know very well: stress. Generated by work, family obligations and the frenetic pace of modern life, it's everywhere. But did you know that behind it lies a key hormone: cortisol? Nicknamed the "stress hormone", cortisol plays an essential role in our survival, helping us to react to difficult situations. However, when produced in excess or over a long period of time, it can become a veritable silent poison for our body and mind. Sleep disorders, weight gain, a weakened immune system... the effects of poorly managed cortisol are numerous and insidious. So how can we keep this hormone under control and preserve our well-being? Let's discover the keys to good cortisol management, so that we can turn stress from an invisible enemy into a controlled ally.
What is cortisol?
Cortisol is a hormone secreted by the adrenal glands from cholesterol. Its secretion follows a circadian rhythm with a peak early in the morning, between 6 and 8 a.m., and a gradual decrease throughout the day to almost zero in the middle of the night.
Cortisol plays a pivotal role in many physiological processes:
Immune function and inflammation The immune system: it is able to inhibit certain immune system responses and has anti-inflammatory effects.
Glucose metabolism Glucose metabolism: helps maintain blood sugar levels by increasing neoglucogenesis (glucose synthesis by the liver) and insulin resistance.
Lipid and protein metabolism Lipid and fat metabolism: stimulates the breakdown of proteins and fats in most tissues (excluding the nervous system).
The cardiovascular system The cardiovascular system: regulates blood pressure and vascular tone, induces vasoconstriction and increases cardiac output.
Urinary system It has a diuretic action.
Cerebral and neuromuscular function It promotes wakefulness, alertness and motivation, and can also influence cognition.
The digestive system The digestive system: it can affect microbiota, intestinal transit time and permeability, as well as nutrient availability.
Another role of cortisol is to cope with stress :
Stress activates the HPA (Hypothalamic-Pituitary-Adrenal) axis. The hypothalamus stimulates the pituitary gland, which in turn stimulates the adrenal glands, responsible for the secretion of cortisol. This cortisol then acts on the various target organs, while exerting what is known as "retrocontrol" to regulate its release. In short: by binding to receptors, it sends information to the hypothalamus and pituitary gland that it is in sufficient quantity to act. These then stop activating its secretion.
In critical moments, the body needs immediate energy for survival. This mobilization of energy is accompanied by the suppression of long-term long-term not essential to immediate survivalsuch as digestion, growth, reproduction and the immune system.
Stress, perceived as a threat, triggers the secretion of catecholamines (adrenaline and noradrenaline) and cortisol.. The latter has a powerful anti-inflammatory action and mobilizes glucose to promote survival and motivate success. It also plays a role in the consolidation of fear-based memories, helping to avoid future threats.
According to the Hans Selye's modelwhen faced with a stressful situation, several stages follow:
Stage 1: The alarm phase
The body first secretes adrenaline. The role of this molecule is to help the body respond to what is interpreted as aggression. Glucose is released into the bloodstream, the heart and breathing speed up to optimize the supply of sugar and oxygen to the muscles, and thus the transformation of sugar into energy: the body is ready to mobilize, and flight or fight is made possible. This binary choice in the face of stress, and all the metabolic reactions that preceded it, have their origins in the time when Man had to fight for his survival, and when his main preoccupations were to eat and not to be eaten.
Stage 2: The resistance phase
This begins after a few minutes, when the stressful situation persists. The body will then try to adapt to the situation and ensure sufficient energy intake to resist. This is when cortisol is released and plays its role. It will be accompanied by other hormones such as endorphins, dopamine and serotonin.
In general, the situation returns to normal, the body regains its state of equilibrium and resumes a natural metabolism, but in the case of chronic stress and therefore exposure repeated too often or continuously, a third phase appears:
Stage 3: The exhaustion phase
The constant release of stress hormones and high energy expenditure simply exhaust the body. Its resources become insufficient, and this last phase not only leads to fatigue and a weakened immune system, but also increases the risk of developing pathologies such as hypertension, type 2 diabetes, asthma and depression.
Cortisol therefore plays a crucial role in the body's stress response the body's response to stress, helping to internal balancebut if it is secreted in excessin the case of chronic stress for example, it can become harmful to health.
Cortisol and civilizational stress
As we have said, our body is set up to react to stress in two ways: fight or flight. fight or flight. But these daysoverwork, relationship difficulties or financial problems have replaced predators as stress factors. And most of the time, fleeing or fighting these situations is, or seems to be, impossible.. The situations persist and the stress continues. Cortisol is released, regulating its secretion via retrocontrol to maintain an effective level, until the day when the receptors on which cortisol binds to exert this retrocontrol tire of being over-used and refuse to bind it. The information no longer reaches the hypothalamus or pituitary gland, which no longer know whether cortisol secretion is sufficient. The stress factor is still there, however, and the HPA axis is still stimulated. Cortisol therefore continues to be released, again and again, resulting in widespread inflammation (the body becomes less sensitive to its anti-inflammatory effects), which can lead to pain, depression, persistent fatigue, sleep disturbance and lowered immune defences, among other things.
How to act for a better balance
The best way to act against cortisol dysregulation is toact against chronic stress. There are several complementary approaches to reducing its impact:
Relaxation:
To better manage your emotions, practice activities such as meditationmeditation yoga or breathing (cardiac coherence, for example) can be beneficial. What they all have in common is that they refocus attention on the body and its sensations so as to avoid focusing on sources of stress and improve well-being. Initial results from mindfulness meditation, for example, show a reduction in blood pressure, insulin resistance and inflammation, as well as an improvement in carbohydrate and lipid parameters. All physiological effects that contribute to better health.
Physical activity:
It reduces sympathetic hyperactivity and activates the parasympathetic systemIt reduces inflammatory processes in the brain and enhances cognitive faculties and memorization processes, which are undermined by stress. It improves mood by promoting secretion of dopamine, serotonin and endorphins. All these mechanisms have a number of benefits for mental health, including stress reduction and resistance, reduced fatigue and improved sleep quality, making physical activity (when not excessive) one of the pillars of good health. one of the pillars of better stress management and, more generally, for good health.
Food :
Some studies have shown a link between the quality of our diet and the presence of stress, anxiety and depression. Frequent consumption of ready-made meals (which are very low in vitamins and high in sugar, particularly fructose, responsible for inflammation, intestinal dysbiosis and insulin resistance, which are responsible for mood and anxiety disorders) or excessive consumption of meats and cured meats was associated with a higher risk of stress. Similarly, the consumption of sugar, while providing initial relief, should be limited. The harmful impact on anxiety of fructose in particular, found in abundance in industrial products, has been studied. A diet rich in diet rich in vitamins and minerals (fruit and vegetables, a small portion of raw food at the start of each meal, steaming, etc.) and omega 3 (small oily fish; eggs from hens fed linseed; vegetable oils such as rapeseed; nuts and seeds).
Energy management :
Feelings of stress and anxiety are often the result of poor energy management. We want to do everything well and quickly, and we neglect moments of pause and recuperation. The sleep is the time when the body and mind recover the mostSo it's essential to take care of it, but don't stop there. Nature walks, creative activities, massages, baths or simple napsIt's also important to take these little breaks, even if it means planning them as you would with your own body. even if it means planning them as you would with your usual activities.. Likewise, it will be beneficial to take breaks during our work sessions. The "pomodoro" technique, which consists of concentrating on your work for 25 minutes, then taking a 5-10 minute break and starting again, then taking a longer 20-25 minute break after two hours of work, can be an interesting approach, but everyone is free to find the technique that suits them.
Cortisol plays an essential role in our bodies and in our ability to react to stressful situations. However, when produced in prolonged excess, it can become a veritable silent poison, disrupting our physical and mental balance. By understanding how cortisol influences our body and mind, we can better act to limit its negative effects. A balanced diet, appropriate physical activity, relaxation techniques and a good night's sleep are all levers for regaining hormonal balance and better managing stress on a daily basis. So, rather than suffering the effects of stress, let's start adopting sustainable habits now to boost our long-term health!
Sources :
https://www.fedecardio.org/je-m-informe/reconnaitre-les-differentes-formes-de-stress/
https://fr.wikipedia.org/wiki/Hans_Selye
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https://hal.univ-lorraine.fr/hal-01947127
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https://www.ncbi.nlm.nih.gov/books/NBK507250/
https://fr.wikipedia.org/wiki/Technique_Pomodoro