Cortisol: What It Is, Symptoms & How to Lower It

Published: 2 September, 2024 | 10'

The networks have been flooded with content about cortisol over these months but, what do you really know about it? Commonly known as “the stress hormone”, cortisol plays a fundamental role in numerous physiological processes. Currently, our society lives at a fast pace that directly affects our bodies. Discover the functions of cortisol and its impact on our health.

What is cortisol and what is its function?

Cortisol is a steroid hormone produced in the adrenal glands located at the top of the kidneys and is then released into the bloodstream to be transported throughout the body. In this way, it reaches its receptors scattered throughout the body's tissues, thus intervening in the nervous, immune, cardiovascular and respiratory systems, among others.

Main functions of cortisol

Cortisol is the main glucocorticoid in the body, hormones that participate in regulating metabolism, the sleep cycle, immune function, and inflammation. It is associated with the stress response, as cortisol levels are altered to modify the body's response to stressful situations, activating certain processes in response to a threat, which is why it is known as “the stress hormone”.

Why does cortisol elevate in response to stress?

The body's autonomic nervous system is divided into the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). Our body is constantly exposed to internal and external stressors. In times of stress, the SNS activates, triggering a series of hormonal and physiological responses.

Our brain (specifically the hypothalamus) is responsible for regulating the appropriate response in stressful situations, such as after a recent surgery or a dangerous situation. Upon detecting the threat, cortisol is released, the synthesis of which is regulated by the hypothalamic-pituitary-adrenal (HPA) axis.

Thus, in a stressful situation that the body recognises as a threat, cortisol rises to trigger gluconeogenesis (the production of glucose), lipolysis (the release of fatty acids from glycerol), and glycogenolysis (the breakdown of glycogen to produce glucose). In this way, we obtain energy to cope. However, if this situation persists for an extended period, it can lead to negative health consequences.

Cortisol also reduces functions that are considered non-essential during that state of stress and alters immune system responses, furthermore inhibiting the functions of the digestive system, reproductive system, and other processes. This alarm system also communicates with the brain regions that regulate mood.

Cortisol and circadian rhythms

The release of cortisol is pulsatile, with levels of this hormone varying throughout the day, being generally higher in the morning upon waking, helping to prepare the body for daily demands, and decreasing throughout the day to reach a minimum at night, which favours rest. It is regulated by genetic and environmental factors, influenced by the sleep-wake cycle and the perception of stress.

Cortisol plays a role in circadian rhythms and in the regulation of energy levels, with its levels potentially influencing sleep cycles and relating to difficulties in falling asleep.

What are the normal levels of this hormone?

To measure cortisol levels, a blood test is required, preferably done in the morning while fasting. Under these conditions, normal values are 5 to 25 mcg/dL or 140 to 690 nmol/L, but it is very important to note that these reference values depend on the time of day the sample is taken and the clinical context of the person. It is also possible to measure levels with a saliva test. Generally, higher levels may indicate stress or the presence of certain conditions.

High cortisol: causes and consequences

The variation of cortisol levels throughout the day is part of the body's natural response to potential harm, danger, or a specific situation that requires it. Precisely in the morning, we have the highest levels, which gradually reduce throughout the day, showing peaks of high cortisol during the day in response to stress on an occasional basis. However, if the body produces too much cortisol constantly, it is usually indicative of other associated conditions.

There are various reasons why the adrenal gland may release too much cortisol, stemming from situations where the body feels threatened by a stressful or compromised situation such as lack of sleep, an unbalanced diet, or certain conditions. Let us look at some of them.

• Chronic stress: the silent enemy

In a stressful situation, our body begins the process of emitting signals from the nervous system, which activates the release of hormones such as adrenaline and cortisol. As an immediate result, the heart rate accelerates and energy levels increase to prepare our body for this situation it detects as threatening, also raising blood glucose levels. Once this situation stabilises, cortisol levels and bodily functions return to their normal state.

When subjected to constant stress, this response remains alongside the production of these hormones, potentially negatively affecting several bodily processes, thereby increasing the risk of triggering certain conditions with symptoms associated with those detailed previously.

• Lack of sleep and inadequate rest

During the course of nocturnal sleep, we go through several stages. For adequate rest to occur, the activity of the HPA axis must decrease during the first half of the night. When this does not happen and it remains overly active, it causes a disruption of sleep phases, which may lead to night awakenings or insomnia.

When the duration of night rest is reduced for an extended period, physiological alterations may appear, such as increased blood pressure or increased cortisol production during the night. Additionally, a review conducted by the National Library of Medicine of the United States in 2020 indicates that sleep disorders can also cause an increase in cortisol during the day.

• Unbalanced diet and excessive caffeine

An unbalanced diet can be directly related to a higher likelihood of experiencing stress or other mood alterations. Additionally, a state of stress can influence our eating habits, making it more challenging to maintain a balanced diet.

Specifically, foods with a high glycaemic index or caffeine act as central nervous system stimulants and may temporarily increase alertness through cortisol production. Therefore, excessive consumption of these foods could lead to the occurrence of constant spikes in the habitual production of this hormone.

• Diseases and medical conditions

Hypercortisolism is a condition in the body characterised by the presence of a uncontrolled amount of cortisol in the body. The possible causes of this excess cortisol are diverse, among which we highlight:

• Prolonged use of glucocorticoids.
• Cushing's syndrome.
• Certain types of tumours that promote uncontrolled release of cortisol in the axis that controls the release of this hormone (hypothalamus, pituitary or adrenal glands).

Stressful situations and severe changes in mood can also lead to increased cortisol levels.

Symptoms of high cortisol: how to recognise it?

In cases where cortisol is produced constantly and remains at high levels outside the previously mentioned situations, it may cause signs such as:

• Irritability.
• Weight gain.
• Acne or other skin signs such as redness.
• Slow healing.
• Weakness or fatigue.
• Headaches.
• Difficulty in concentrating.
• High blood pressure.

These symptoms depend on the causative factor and, in most cases, do not have to occur solely due to high cortisol levels.

Physical changes: weight gain, fatigue, skin issues

Among the various factors that influence our weight, hormonal regulation is of great importance. In fact, there are situations such as stress that can alter their levels. In the case of glucocorticoids, an increase in their levels favours the consumption of foods considered "comforting", those that provide short-term relief and are high in fat and sugar, meaning they are calorie-dense. This is why high glucocorticoid levels, by interfering with eating habits, can be related to weight gain.

On the other hand, one might experience feelings of exhaustion or fatigue due to the role played by the HPA axis in the stress response aimed at lowering cortisol levels, as the brain consumes a large part of the body's energy.

There is a term popularly known as "adrenal fatigue" to refer to these symptoms of tiredness or exhaustion during periods of stress. However, there is no evidence at this time that demonstrates that the cause stems from the constant production of hormones in the adrenal glands due to stress.

These physical changes are also visible on our skin. As we have mentioned, cortisol receptors are found in most tissues of the body, including the skin. In the face of chronic stress, the continuous production of cortisol can have negative effects on the skin barrier, reducing the thickness of the dermis and thereby increasing skin sensitivity and favours the appearance of skin conditions. Cortisol has also been linked to inflammation, affecting the wound healing process and influencing sebum production. Additionally, due to increased inflammation, skin conditions can worsen with stress, such as the appearance of eczema, psoriasis, dermatitis, rosacea, or acne outbreaks.

Emotional disturbances: anxiety, irritability, depression

The consequences of high cortisol levels due to prolonged stress also affect us emotionally, presenting a lack of motivation, irritability, bad mood, or feelings of sadness. Depending on the source of stress, it is common to experience episodes of anxiety and changes in behaviour.

Cognitive problems: difficulty concentrating, memory issues

The impact of cortisol levels on the memory process appears during prolonged periods of stress, especially if it affects our nightly rest. One of the most important physiological implications of sleep is to consolidate in memory the most relevant events of our daily life.

Moreover, our brain involves several areas in its response to stress, and its prolonged action can cause neuronal degeneration directly affecting memory and learning processes.

How to reduce cortisol

First and foremost, it is essential to understand that unless there is some pre-existing condition, cortisol levels rise in response to stress and it is a normal process of our body. The main issue lies in those situations where this state of stress is maintained for a long period and affects various internal processes with the symptoms already mentioned earlier. Therefore, we will focus on learning to manage stress episodes with recommendations and guidelines that we can implement in our daily lives.

Relaxation techniques and stress management

Firstly, learning to recognise stressful thoughts to try to avoid feelings of alarm or shock as much as possible is useful to combat stress in various situations. It involves paying attention every day to the thoughts that cause stress to become fully aware and learn to process them. Some initial signs may be rapid breathing, a high heart rate, or negative and repetitive thoughts. Thus, focusing on the awareness of our mental and physical state can turn us into observers without allowing immediate nervousness and having a conscious and controlled reaction. This process is also known as mindfulness, and regular practice could reduce cortisol levels in people who typically suffer from stress and/or anxiety according to some studies.

Meditation is also useful in this regard, as it aims for a similar goal of training the mind to focus and redirect intrusive or negative thoughts that could worsen the state of stress.

Dietary changes

Appropriate eating habits are essential for maintaining internal processes and physical stability, but also for mental balance and helping to control cortisol.

Practicing a mindful diet will help avoid food anxiety and eating habits related to stress such as constant eating anxiety. Being aware of the signals of hunger and satiety, as well as paying attention to the taste and texture of food, eliminating distractions, will be highly beneficial.

Furthermore, the consumption of added sugars, refined grains and saturated fats is related to higher cortisol levels compared to a diet rich in fruits, vegetables, whole grains, and polyunsaturated fats.

Physical exercise

Regular physical exercise has been associated with a reduction in stress levels and, consequently, cortisol, but also as a remedy against stress factors due to its action on the central nervous system. Exercising stimulates the production of endorphins, hormones that promote good mood, happiness and help manage stress.

Rest and restorative sleep

The nightly rest has a significant effect on cortisol levels as we have mentioned, in addition to affecting our metabolism and causing an increase in hormones related to hunger and appetite. The following guidelines will help you create a suitable sleep routine:

• Follow the same routine before bed each day (take a shower, read a book, meditate, etc.).
• Exercise several hours before going to bed.
• Go to bed and wake up at the same time each day as much as possible.
• Limit caffeine intake and avoid having it at least 6 hours before bedtime.
• Reduce exposure to artificial light and blue light from screens at night.

How to control cortisol in the long term

In addition to following the previous guidelines for controlled stress management, there are tests to measure cortisol levels in the blood in order to monitor and detect possible clinical conditions.

Importance of medical consultation

If you have several symptoms of high cortisol, as described above, or if you suffer from prolonged stress that affects your daily life, it is advisable to consult a healthcare professional who can recommend tests to determine the state of your cortisol levels or other hormones.

Cortisol monitoring and tests

• Cortisol analysis in urine and blood to determine your levels. Normally blood tests are carried out first thing in the morning, while urine analysis may involve collecting the sample over a 24-hour period to see its evolution.
• Salivary cortisol test. This test is usually done to detect Cushing's syndrome, where a sample is collected at night, as under normal circumstances cortisol levels drop before going to sleep.

If you want to know more about physical well-being…

• Exercises to maintain muscle mass
• How to maintain physical fitness in summer
• Intermittent fasting: How to do it correctly?

Content reviewed by specialists from the Scientific Information area of MARNYS. This article is informative and does not replace a consultation with a specialist.