Benefits of Cold Showers & Cold Plunge
The Science of Cold Water Exposure:
Cold water exposure become increasingly popular in recent years due to its potential health benefits. It has been suggested that cold exposure to water can activate brown adipose tissue, help boost the immune system, enhance resilience to stress, enhance circulation, burn calories, reduce inflammation, and boost muscle recovery. However, there is a lack of well-structured scientific evidence in relation to these mechanisms.
Cold-water exposure poses a challenge to the body and the body's organ systems. Therefore, the body has to administer homeostatic controls in order to maintain an appropriate temperature in the brain and organs. These homeostatic controls include thermoregulation and skin blood perfusion, shivering thermogenesis, non-shivering thermogenesis, and cardiopulmonary response.
So What happens to our bodies when we are exposed to cold Temperatures?
Skin Blood Perfusion
The heat of our skin is regulated by blood flow. Blood is transported to the dermis (outer layer) of the skin through a network of blood vessels and skin capillaries. Changes in temperature inhibit vasoconstriction (narrowing) or vasodilation (widening) of blood-specific networks of blood vessels that are used for heat exchange between the skin surface and the environment. Short circuit vessels function in thermoregulation by opening or widening in situations when the body needs to lose heat and closing when the body needs to conserve heat.
Shivering thermogenesis
Shivering is the body’s core response to cold exposure and is defined as a continuous contraction of skeletal muscles in the body. This increased muscle activity requires energy and thus causes a high metabolic rate, and generation of heat. The generation of a higher metabolic rate allows your body to burn more calories than normal.
Non-shivering thermogenesis
When the body induces a state of non-shivering thermogenesis, brown adipose tissue is able to produce excess heat. Mitochondria in brown adipose tissue can burn fat and produce large quantities of heat. This heat is then released directly into the bloodstream. The increase in the bodi’s need to generate heat causes an increase in metabolism.
Cold Water Exposure Impact on the Body
As the body experiences cold exposure and inhibits thermoregulation controls, this can induce various outcomes. Let’s discuss some of the benefits and their mechanisms.
01. Hormones:
Deliberate cold exposure can positively benefit our body’s metabolic function and insulin resistance because of its impact on hormones.
Cold exposure can have an impact on hormone levels, and both plasma adrenocorticotropic hormone (ACTH) and cortisol levels seem to decrease significantly after a short time of regular cold-water exposure. Additionally, with cold water exposure, the plasma concentration of norepinephrine will significantly increase inhibiting the "fight-or-flight" response within the body, even after regular use of cold therapy. Increases in norepinephrine may play a role in pain alleviation and increasing cold tolerance by non-shivering thermogenesis.
Further, regular cold-water exposure can have an impact on parathyroid and thyroid hormones. A study done on cold water swimmers showed an increase in parathyroid hormone (PTH) and thyroid-stimulating hormone (TSH), as well as free T3. The increase in PTH can cause the body to lean toward a metabolic preference for lipids and increase brown adipose tissue function, increasing the browning of white adipose tissue. Brown adipose tissue supports healthy body weight and metabolism and burns more calories compared to white adipose tissue. This can help partly explain the mechanism by which cold water exposure is linked to stimulating brown fat and increasing metabolism [2].
Further, insulin levels are impacted significantly by cold exposure. One study showed that repeated cold-water immersions increased insulin sensitivity and decreased insulin concentrations [3]. This finding suggested a positive health effect on insulin resistance, and a positive impact on diseases such as diabetes.
02. Reduced Inflammation
Cold water exposure can have an impact on the response of the immune system.
Cold water exposure can increase plasma concentration of interleukin (IL)-6, total T lymphocytes (CD3), T helper cells (CD4), T suppressor cells (CD8), activated T and B lymphocytes (HLA-DR) were found. All of these immune cells are important in the proper function of the immune system and increased concentration can lead to an increase in immune function.
Further, cold water exposure can cause a decreased plasma uric acid concentration, which is an important plasma antioxidant. This may be caused by the formation of oxygen radicals, which is further supported by increased oxidative stress (reduced glutathione). The concentration of oxidized glutathione has been shown in studies to be significantly decreased in winter swimmers in comparison to non-winter swimmers. This may be explained by the body’s adaptive response to repeated exposure to oxidative stress, which results in increased tolerance to stress [4].
The popular Whim Hoff method backbone lies on a backbone of increased tolerance to stress. When inducing a calming breath under stressful situations, your body may become more tolerant to both acute and chronic stress.
03. Improved Mental Health
Cold water immersion can help increase resilience to stress.
Cold water exposure is a purposeful exposure to extreme stress.As discussed above it is hypothesized that purposeful physiological stressors may cause the increased function of the brain and increased tolerance to stress. [5]. Cold water exposure causes an increase in plasma noradrenaline, beta-endorphin, and synaptic release of noradrenaline in the brain due to stress. This may inhibit a positive effect on mental health status and brain development [5].
Further, many people report alertness after using cold exposure. Deliberate cold exposure causes an increase in the neurochemicals epinephrine (aka adrenaline) and norepinephrine (aka noradrenaline), which can cause an increase in both energy and focus [1].
04. Improved Muscle Recovery
According to many studies, cold water therapy could prevent injuries and help maintain the optimal performance of athletes.
A study comparing professional athletic recovery with and without cold water exposure measured markers of sprint performance, muscle function, muscle soreness, biochemical markers associated with damage, and oxidative stress. The group that included cold water exposure had improved recovery time and reduction of Creatine kinase which is associated with reduced muscle damage, increased muscle power, and decreased muscle soreness [6].
While there are clearly many benefits to cold water exposure, further controlled studies may help to understand these reported benefits. It is important to consider many factors when choosing a cold exposure protocol to experience some of these benefits. There are also some potential implications of using cold exposure, particularly AFTER hypertrophy or strength training. Timing can be an extremely important factor when using health mechanisms such as cold therapy. When using cold water therapy after strength or hypertrophy training studies suggest blunted muscle fiber hypertrophy, potentially via increased catabolism (breakdown) and reduced anabolism (building/repair) of skeletal muscle protein [7]. It is unknown if Cold showers have the same effect as cold immersion.
How to Add Cold water therapy to your routine:
Personally, I implement cold showers on a daily basis, along with cold immersion whenever I have access to a cold plunge. When you first enter to cold water your body will go into a state of fight or flight. In order to allow your body to go into parasympathetic or rest-and-digest. Allowing your body to relax in this purposeful stressed state will help you become more resilient to the stresses of daily life.
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Esperland, D., de Weerd, L., & Mercer, J. B. (2022). Health effects of voluntary exposure to cold water - a continuing subject of debate. International journal of circumpolar health, 81(1), 2111789.
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Gibas-Dorna, M., Checinska, Z., Korek, E., Kupsz, J., Sowinska, A., Wojciechowska, M., Krauss, H., & Piątek, J. (2016). Variations in leptin and insulin levels within one swimming season in non-obese female cold water swimmers. Scandinavian journal of clinical and laboratory investigation, 76(6), 486–491.
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Atzmon G, Pollin TI, Crandall J, et al. Adiponectin levels and genotype: a potential regulator of life span in humans. J Gerontol A Biol Sci Med Sci. 2008;63(5):447–453.
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Siems, W. G., van Kuijk, F. J., Maass, R., & Brenke, R. (1994). Uric acid and glutathione levels during short-term whole body cold exposure. Free radical biology & medicine, 16(3), 299–305.
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Shevchuk N. A. (2008). Adapted cold shower as a potential treatment for depression. Medical hypotheses, 70(5), 995–1001.
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Ihsan, M., Watson, G., Lipski, M., & Abbiss, C. R. (2013). Influence of postexercise cooling on muscle oxygenation and blood volume changes. Medicine and science in sports and exercise, 45(5), 876–882.
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Fyfe, J. J., Broatch, J. R., Trewin, A. J., Hanson, E. D., Argus, C. K., Garnham, A. P., Halson, S. L., Polman, R. C., Bishop, D. J., & Petersen, A. C. (2019). Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. Journal of applied physiology (Bethesda, Md. : 1985), 127(5), 1403–1418.
