How does the endocrine system work?
The endocrine system is a complex system of glands producing hormones which control pretty much every function within the body. It’s an intricate, closely regulated system which works similar to a thermostat. If there’s too much hormone being produced by a gland, the system switches off to keep things in status quo. If there’s too little hormone being produced, the system switches on and the gland makes more. Basically, keeping the body nicely balanced.
Cortisol – the stress hormone
The number one stress hormone produced in our body is cortisol – a steroid hormone vital to the fight or flight response, essential for survival. For example, predator appears, your body is primed to respond predominantly by cortisol (as well as other factors). Cortisol has a number of other effects, which include regulation of blood sugars and metabolism, suppression of inflammation, control of salt and water balance, control of bone formation as well as many other important physiological processes necessary for cells and tissues to function.
Where does cortisol come from?
It is mainly produced by the adrenal glands – important endocrine glands which sit just above the kidneys. Its production is closely regulated by other hormones produced mainly within the brain. The centres in the brain which regulate most hormones are the hypothalamus and pituitary gland and these are the “control centres” of the endocrine system.
What happens when things go wrong with production of cortisol?
In usual circumstances, the brain can control how much cortisol is produced from the adrenal gland. However sometimes the system does malfunction. Too much unregulated cortisol production results from a condition called Cushing’s syndrome or disease and too little cortisol production results from conditions such as autoimmune adrenal insufficiency (Addison’s disease). These are serious medical conditions requiring treatment with medications or an operation in some cases.
How does psychological or personal stress affect cortisol?
A number of factors can be associated with a chronically elevated cortisol (but don’t result in Cushing’s). These factors include sleep deprivation and mood disturbance such as depression and physical or mental illness (Qin et al, 2016). There is little scientific evidence on long-term effects of chronic stress on cortisol. We know that untreated Cushing’s syndrome can result in conditions such as diabetes, hypertension, depression and osteoporosis (Pivonello, 2017) . There’s no evidence as yet to suggest chronic psychological stress carries with it the same risks.
How does psychological or personal stress affect other hormones?
Certain hormones are at higher risk of disruption by external stressors. Sex hormones are particularly vulnerable, as stress can interfere with hormones produced in the hypothalamus that control the release of sex hormones which include oestrogen and testosterone. Stress can interfere with the menstrual cycle, and if prolonged may lead to problems with fertility (Lania, 2019). And men suffering with chronic stress are also at risk of fertility issues (Nordkap, 2016). The thyroid gland is also sensitive to stress, particularly that associated with critical illness, resulting in reduced production of thyroid hormone (Gibson, 2005).
Do I need to worry about stress affecting my hormones?
In today’s day and age, it’s almost impossible to not feel stressed out at some point. Fortunately, the endocrine system and the associated hormones are incredibly good at coping with a certain level of stress, regulating hormones naturally by switching other hormones on or off. Chronic stress can upset the balance of certain hormones, and this can result in serious issues such as infertility. If you have concerns, talk to your GP or endocrinologist.
This blog post was written by, Dr Anjali Amin. Anjali is a Consultant in Diabetes & Endocrinology in London and has a PhD looking at the effect of protein on appetite and gut hormones. Anjali is a mum of 3 children and a keen advocate of healthy eating. Instagram - @thekitchendoctorandmum
Qin DD, Rizak J, Feng XL, Yang SC, Lü LB, Pan L, Yin Y, Hu XT. Prolonged secretion of cortisol as a possible mechanism underlying stress and depressive behaviour. Sci Rep. 2016 Jul 22;6:30187. doi: 10.1038/srep30187. PubMed PMID:27443987; PubMed Central PMCID: PMC4957121.
Pivonello R, De Martino MC, De Leo M, Simeoli C, Colao A. Cushing's disease: the burden of illness. Endocrine. 2017 Apr;56(1):10-18. doi: 10.1007/s12020-016-0984-8. Epub 2016 May 17. Review. PubMed PMID: 27189147.
Lania A, Gianotti L, Gagliardi I, Bondanelli M, Vena W, Ambrosio MR.Functional hypothalamic and drug-induced amenorrhea: an overview. J Endocrinol Invest. 2019 Sep;42(9):1001-1010. doi: 10.1007/s40618-019-01013-w. Epub 2019 Feb 11. Review. PubMed PMID: 30742257.
Nordkap L, Jensen TK, Hansen ÅM, Lassen TH, Bang AK, Joensen UN, Blomberg Jensen M, Skakkebæk NE, Jørgensen N. Psychological stress and testicular function: a cross-sectional study of 1,215 Danish men. Fertil Steril. 2016 Jan;105(1):174-87.e1-2. doi: 10.1016/j.fertnstert.2015.09.016. Epub 2015 Oct 23. PubMed PMID: 26477499.
Gibson SC, Hartman DA, Schenck JM. The endocrine response to critical illness: update and implications for emergency medicine. Emerg Med Clin North Am. 2005 Aug;23(3):909-29, xi. Review. PubMed PMID: 15982552.
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