Why Is The Primary Stress Hormone Cortisol Important For Health?

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Cortisol prepares your body for fight-or-flight response, assists in glucose metabolism and regulates blood sugar and suppresses inflammation and immune response. Cortisol levels ebb as soon as the danger is averted. But stress can cause cortisol levels to stay high on a continuous basis. This leads to higher risk of obesity, cardiovascular disease and cognitive ability.

There are situations when your body needs to get quickly alert and active for a short duration, say when you are crossing a busy road (or in prehistoric times when you were strolling in the jungle and suddenly found yourself facing a wild angry elephant). Cortisol is the go-to hormone in such situations.

When you’re faced with a stressor, cortisol, popularly known as the fight-or-flight hormone, is produced by the adrenal gland and then released into the blood so it is easily transported to the entire body. Almost every cell has cortisol receptors, hence it can have different actions depending on the cell it is acting upon. Broadly, the entire body works in concert to make energy available and to be prepared to expend it, if required. But then, this is only supposed to be a short term affair. When cortisol released in the blood reaches the brain, the pituitary gland  shuts off further production of cortisol. Its a self-regulating switch.

Why is Cortisol Important?

Some important functions of cortisol are:

  • Proper glucose metabolism
  • Regulation of blood pressure
  • Insulin release for blood sugar maintenance
  • Immune function
  • Inflammatory response

Let’s understand how cortisol can affect several body functions.

The Immune System

Cortisol makes the body put down whatever its doing at that moment, sit up and take notice. By design, it tends to push other functions, like the immune system, to the back burner.  Inflammatory response, a key mechanism of the body to fight against external threats, is suppressed temporarily. This is perfectly fine in the short term. However, there are conditions like continuous stress that cause the cortisol on-off switch to stay on, perpetually. In such cases, the immune system, always on the back-burner, is weakened, making you susceptible to various pathogens.

Dig deeper and the situation is much more complex. Cortisol has both suppressive and non-suppressive effects on the immune system. Cortisol suppresses immune system elements concerned with long term effects, while enhancing those with short term (innate) impact.1


During the third trimester, exposure to maternal cortisol is essential for the maturation of fetal lungs and for the preparation of the fetus for delivery.  Elevated free cortisol would be needed to maintain homeostasis.2 However, elevated cortisol levels are also suspected to negative affect the child’s cognitive skills.3

Cardiovascular Function

Cortisol can help in immediate flight-or-fight responses but not perpetually. It constricts the blood vessels, raising blood pressure to allow delivery of oxygenated blood. Over time, this arterial constriction can lead to plaque buildup and wall damage, leading to cardiovascular disease. This explains why those who are under chronic prolonged stress are at a higher risk of heart disease.4


Stress triggers cortisol production. The body anticipates quick expenditure of energy and a dip in energy reserves thereafter. High blood glucose levels along with insulin suppression lead to cells that are starved of glucose. When these cells are crying out for energy, one way to regulate this is by sending hunger signals to the brain. Food is comforting – it signals the brain that everything is OK. However, in a chronic stress situation, while consumption of food provides temporary relief, extra energy is not getting expended. All this extra food sticks around, either as excess fat or as toxic resdiue. This can lead to obesity and several other diseases.5

Other Diseases

Those suffering from Alzheimer’s have been found to have higher concentrations of cortisol.6

Excess cortisol may also lead to Cushing’s Syndrome. This may occur if you take glucocorticoid steroid hormone pills, non-cancerous or cancerous tumor in the pituitary gland or an abnormality of the adrenal gland.7

Long-term stress and elevated cortisol have also been linked to insomnia, chronic fatigue syndrome, thyroid disorders, dementia, depression, and other conditions.

References   [ + ]

1. GALON, JÉRÔME, et al. “Gene profiling reveals unknown enhancing and suppressive actions of glucocorticoids on immune cells.” The FASEB Journal 16.1 (2002): 61-71.
2. Nolten, W. E., and P. A. Rueckert. “Elevated free cortisol index in pregnancy: possible regulatory mechanisms.” American journal of obstetrics and gynecology 139.4 (1981): 492-498.
3. LeWinn, Kaja Z., et al. “Elevated maternal cortisol levels during pregnancy are associated with reduced childhood IQ.” International Journal of Epidemiology (2009): dyp200.
4. Whitworth, Judith A., et al. “Cardiovascular consequences of cortisol excess.” Vascular health and risk management 1.4 (2005): 291.
5. Yau, Yvonne HC, and Marc N. Potenza. “Stress and eating behaviors.” Minerva endocrinologica38.3 (2013): 255.
6. Davous, Patrick. “Cortisol and Alzheimer’s disease.” (1987).
7. Cushings Syndrome, National Institute of Diabetes and Digestive and Kidney Diseases
CureJoy Editorial

The CureJoy Editorial team digs up credible information from multiple sources, both academic and experiential, to stitch a holistic health perspective on topics that pique our readers' interest.

CureJoy Editorial

The CureJoy Editorial team digs up credible information from multiple sources, both academic and experiential, to stitch a holistic health perspective on topics that pique our readers' interest.