In our previous article, Hormones 101, we briefly covered what a hormonal imbalance is using the analogy of a toy factory. In this article by our founder, she will discuss why hormones matter in chronic illness and how hormones link to overall health.

To quickly recap what a hormonal imbalance is – a hormonal imbalance is when there is too little or too much of a hormone. This can either be short-term or long-term, causing significant bodily changes that can potentially lead to conditions that may require treatment. Some common examples you may have heard of include Polycystic Ovary Syndrome (PCOS), diabetes, and hypothyroidism (low thyroid hormone levels).

So how do hormones affect the systems of the body?

Hormones affect every part of your body - every tissue and every cell. Examples of how they interact with the major systems of the body and influence our health are outlined below.

The endocrine system – also known as the hormonal system – consists of a network of glands (glands are special organs or a group of specialised cells) that produce and release specific hormones into your bloodstream with special roles that can help with stress regulation, growth, metabolism and reproduction[1].

The cardiovascular system – hormones, such as adrenaline (epinephrine) and noradrenaline (norepinephrine) play a crucial role in regulating cardiac activity, such as increasing heart rate, blood pressure and the contractility of the heart muscle[2]. Reproductive hormones such as oestrogen play an important role in cardiovascular health. In premenopausal women, oestrogen helps maintain healthy levels of cholesterol however as women approach menopause and oestrogen levels begin to drop, research has shown that decreases in oestrogen are linked to an increase in the risk of heart disease where postmenopausal women are more at risk of developing high blood pressure and high cholesterol[3].

The respiratory system—which includes the lungs, airways, and associated muscles—functions in conjunction with key hormones to maintain effective respiratory processes and eliminate waste gases. For instance, during periods of stress, hormones such as cortisol and adrenaline cause an increase in respiratory rate, activating the system to accommodate heightened physiological demands[4].

The reproductive system - responsible for the production of eggs and sperm as well as the development of offspring, is regulated by hormones involved in puberty and menstruation. Other hormones, such as elevated cortisol levels, may affect menstrual cycles, ovulation, and pregnancy. Thyroid hormone levels also influence the reproductive system where reduced thyroid function can result in irregular menstrual cycles, while increased thyroid activity may be associated with conditions such as ovarian cysts[5].

The immune system – our personal defense system that works 24/7 to protect us from bacteria, viruses and other harmful invaders are intricately linked with our hormones to ensure constant communication and coordination so our bodies function well and remain healthy. For example, our thyroid hormones (T3 and T4), play an important role in immune function. When your thyroid functions properly and helps regulate the production and activity of immune cells, your body can effectively respond to infections without overreacting[6]. However, when there is an imbalance, the impact on the immune system and function can be significant. Examples of autoimmune diseases linked to thyroid dysfunction are Graves’ disease and Hashimoto’s disease.

The skeletal system – The human skeletal system consists of 206 bones that function to produce blood cells, store and maintain minerals, and regulate hormones. For instance, osteocalcin is a hormone produced by osteoblasts, the cells responsible for bone formation[7], and it is involved in insulin regulation and blood sugar maintenance. Oestrogen, present in women, slows the process of bone breakdown. After menopause, reduced oestrogen levels are associated with an increased risk of osteoporosis due to bone loss[8].

The Integumentary system (Skin) – also known as our skin, which is the largest organ of our body, not only acts as a protective barrier, but also interacts closely with our hormones. For example, oestrogen helps promote collagen production to keep our skin firm and elastic however as we grow older, collagen production decreases where there is less oestrogen and hence our skin becomes thinner and less firm[9]. Another example of how the integumentary system is linked to our hormones is when we are stressed and as a result, have high cortisol levels (the stress hormone). High levels of cortisol can worsen current skin conditions, such as eczema and acne by triggering more inflammation and slow down wound healing[10].

References

1] The Johns Hopkins University. (2025). Hormones and the Endocrine System. Retrieved from https://www.hopkinsmedicine.org/health/conditions-and-diseases/hormones-and-the-endocrine-system

[2] Healthdirect. (2023). Adrenaline. Retrieved from https://www.healthdirect.gov.au/adrenaline

[3] Ryczkowska, K., Adach, W., Janikowski, K., Banach, M., & Bielecka-Dabrowa, A. (2022). Menopause and women's cardiovascular health: is it really an obvious relationship?. Archives of medical science : AMS, 19(2), 458–466. https://doi.org/10.5114/aoms/157308

[4] Thau L, Gandhi J, Sharma S. Physiology, Cortisol. [Updated 2023 Aug 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538239/

[5] P, H. H., G, S., K, P., Penumalla, S., & Kandimalla, R. (2024). Hypothyroidism and Its Impact on Menstrual Irregularities in Reproductive-Age Women: A Comprehensive Analysis at a Tertiary Care Center. Cureus, 16(6), e63158. https://doi.org/10.7759/cureus.63158

[6] Wenzek, C., Boelen, A., Westendorf, A. M., Engel, D. R., Moeller, L. C., & Führer, D. (2022). The interplay of thyroid hormones and the immune system - where we stand and why we need to know about it. European journal of endocrinology, 186(5), R65–R77. https://doi.org/10.1530/EJE-21-1171

[7] Moser SC and van der Eerden BCJ (2019) Osteocalcin—A Versatile Bone-Derived Hormone. Front. Endocrinol. 9:794. doi: 10.3389/fendo.2018.00794

[8] Australian Menopause Society. (2025). Osteoporosis. Retrieved from: https://menopause.org.au/hp/information-sheets/osteoporosis#:~:text=Oestrogen%20plays%20an%20important%20role,Ovarian%20InsufficiencySpontaneous%20Premature%20Ovarian%20Insufficiency).

[9] Verdier-Sévrain S, Bonté F, Gilchrest B. Biology of estrogens in skin: implications for skin aging. Exp Dermatol. 2006 Feb;15(2):83-94. doi: 10.1111/j.1600-0625.2005.00377.x. PMID: 16433679.

[10] University of Utah Health. (2024). Stressed out skin: the link between stress and skin health. Retrieved from: https://healthcare.utah.edu/healthfeed/2024/01/stressed-out-skin-link-between-stress-and-skin-health