Cortisol
Published: Jul 17, 2023
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Updated: Jul 23, 2023
Written by Oseh Mathias
Founder, SpeechFit
Cortisol is a steroid hormone that belongs to the class of glucocorticoids[1].
It is produced and released by the adrenal glands, which are small glands located on top of the kidneys. Cortisol plays a crucial role in regulating various bodily processes and is involved in the body's response to stress.
The secretion of cortisol follows a diurnal rhythm, with levels being highest in the morning and gradually decreasing throughout the day[2]. It is influenced by the body's internal clock and regulated by the hypothalamus, pituitary gland, and adrenal glands, collectively known as the hypothalamic-pituitary-adrenal (HPA) axis[3].
Cortisol has numerous functions in the body, including:
Stress Response: Cortisol is often referred to as the "stress hormone" because it plays a vital role in the body's response to stress [5]. When a person encounters a stressful situation, the hypothalamus releases corticotropin-releasing hormone (CRH), which signals the pituitary gland to release adrenocorticotropic hormone (ACTH). ACTH then stimulates the adrenal glands to produce and release cortisol into the bloodstream [6]. Cortisol helps the body respond to stress by increasing energy availability, mobilizing resources, and suppressing non-essential functions such as digestion and reproductive processes [7].
Metabolism Regulation: Cortisol is involved in regulating metabolism. It influences the breakdown of proteins, fats, and carbohydrates, increasing blood sugar levels and providing the body with a readily available source of energy during stressful situations [8].
Immune System Regulation: Cortisol has immunosuppressive effects, meaning it helps regulate the immune response [9]. It reduces inflammation and inhibits certain immune system components, which can be beneficial in short-term stress responses. However, chronic or prolonged exposure to elevated cortisol levels can weaken the immune system and increase the risk of infections [10].
Blood Pressure Regulation: Cortisol influences blood pressure by regulating the responsiveness of blood vessels to other substances that control blood vessel diameter [11]. It also affects the balance of sodium and water in the body, which can impact blood pressure levels [12].
While cortisol is essential for normal physiological function, long-term exposure to elevated cortisol levels, such as chronic stress, can have negative effects on health. It can contribute to various health issues, including impaired cognitive function, weakened immune system, metabolic disorders, and mood disturbances [13].
Oseh is a software engineer, entrepreneur and founder of SpeechFit. Oseh is passionate about improving health and wellbeing outcomes for neurodiverse people and healthcare providers alike.
References
Society for Endocrinology. (n.d.). Cortisol | You and Your Hormones from the Society for Endocrinology. http://www.yourhormones.info/hormones/cortisol/
Clow, A., Hucklebridge, F., Stalder, T., Evans, P., & Thorn, L. (2010). The cortisol awakening response: More than a measure of HPA axis function. Neuroscience & Biobehavioral Reviews, 35(1), 97-103. https://doi.org/10.1016/j.neubiorev.2009.12.011
Ulrich-Lai, Y. M., & Herman, J. P. (2009). Neural regulation of endocrine and autonomic stress responses. Nature Reviews Neuroscience, 10(6), 397-409. https://doi.org/10.1038/nrn2647
Society for Endocrinology. (n.d.). Cortisol. You and Your Hormones. Retrieved July 23, 2023, from https://www.yourhormones.info/hormones/cortisol/
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Kyrou, I., & Tsigos, C. (2007). Stress hormones: physiological stress and regulation of metabolism. Current Opinion in Pharmacology, 7(6), 598-603. https://doi.org/10.1016/j.coph.2007.09.001
Elenkov, I. J., & Chrousos, G. P. (2002). Stress hormones, Th1/Th2 patterns, pro/anti-inflammatory cytokines and susceptibility to disease. Trends in Endocrinology & Metabolism, 10(9), 359-368.
Segerstrom, S. C., & Miller, G. E. (2004). Psychological stress and the human immune system: a meta-analytic study of 30 years of inquiry. Psychological bulletin, 130(4), 601.
Whitworth, J. A., Williamson, P. M., Mangos, G., & Kelly, J. J. (2005). Cardiovascular consequences of cortisol excess. Vascular health and risk management, 1(4), 291–299.
Korte, S. M., Koolhaas, J. M., Wingfield, J. C., & McEwen, B. S. (2005). The Darwinian concept of stress: benefits of allostasis and costs of allostatic load and the trade-offs in health and disease. Neuroscience & Biobehavioral Reviews, 29(1), 3-38.
McEwen, B. S. (2008). Central effects of stress hormones in health and disease: Understanding the protective and damaging effects of stress and stress mediators. European journal of pharmacology, 583(2-3), 174-185.