The Brain
Plunging into ice cold water activates your fight or flight response, aka the sympathetic nervous system. This survival instinct begins a release of adrenaline and noradrenaline to prepare your body to take action. The cold shock protein, RBM3, is also upregulated and credited with cognitive repair, circadian regulation, and system homeostasis. By calming your mind with your breath during this response, you train your body to deal with an extreme stress with a clear and focused mind. Following cold exposure, your brain continues to release elevated levels of dopamine, an essential chemical associated with pleasure/reward system. It also raises your baseline level of dopamine, bringing more joy into everyday activities. The complete realm of neurological benefits is still outside of our current scientific understanding, but what we do know is mind blowing!
Immune Response
The cold plunge shifts your body into hyperdrive, activating the immune system to produce more white bloods cells, the ones that aid in fighting off infection. Studies have also shown that in addition to white blood cell upregulation, red blood cell and platelet counts also increase for a period following cold exposure.
Cardiovascular Response
During the initial shock of the ice bath, your body's survival instinct recalls blood from the extremities to the vital organs, scientifically deemed "peripheral vasoconstriction." After getting out of the cold plunge, your body performs the opposite phenomenon by recirculating the warm blood from your core out to your extremities, known as "peripheral vasodilation." This process improves your circulatory system's ability to self regulate when exposed to cold stimuli. It serves as a shock to the system, oxygenating cells and putting positive stress on the heart for longterm longevity. The large movement of blood helps detoxify and aid in faster recovery.
Metabolic Uptick
The survival response forces your body to rapidly begin producing heat by burning calories following immersion into the cold plunge. It also activates the body to convert white fat into brown fat, the fat responsible for keeping your body regulated in the cold. Brown fat burns energy when activated by noradrenaline following cold exposure in an effort to regulate the body's temperature. The best metabolic response can be achieved by allowing your body to reheat on its own following a cold plunge, use exercise and deep breathing to reheat naturally, take it a level further by not using a towel to dry off.
This is not a conclusive list of benefits and cold water therapy does not come without risk.
Citations
Avila-Gomez, Paulo, et al. “Cold Stress Protein RBM3 Responds to Hypothermia and Is Associated with Good Stroke Outcome.” OUP Academic, Oxford University Press, 4 June 2020, https://academic.oup.com/braincomms/article/2/2/fcaa078/5851422.
Huberman, Andrew. “The Science & Use of Cold Exposure for Health & Performance.” Huberman Lab, 20 June 2022, https://hubermanlab.com/the-science-and-use-of-cold-exposure-for-health-and-performance/.
Ivanova YM, Blondin DP. Examining the benefits of cold exposure as a therapeutic strategy for obesity and type 2 diabetes. J Appl Physiol (1985). 2021 May 1;130(5):1448-1459. doi: 10.1152/japplphysiol.00934.2020. Epub 2021 Mar 25. PMID: 33764169.
“What Are the Benefits of Cold Therapy?” Wim Hof Method, Wim Hof, https://www.wimhofmethod.com/cold-therapy.