The benefits of cold water immersion
Reasons to take the plunge
Cold water immersion - there are so many ways to do it: cold showers, filling your bathtub (or wheelie bin) with water and ice, in a cold shower, in a lake, in the sea, in a river – the list goes on. However you get your cold on, there’s a bundle of health and wellbeing benefits waiting for you when you practice regularly, so let’s dive into the detail.
Reduced muscle soreness
Athletes have long relied on cold water immersion to manage delayed onset muscle soreness (DOMS). Cold water immersion constricts the blood vessels, temporarily reducing blood flow to the muscles. This limits the influx of inflammatory cells that contribute to muscle soreness and tissue breakdown [1]. The cold acts as a natural pain reliever with the low temperature numbing the nerve endings and temporarily reducing the perception of soreness and discomfort [2]. This can provide immediate relief and allow for greater mobility and function after exercise.
The initial vasoconstriction (the natural restriction of blood flow) is followed by vasodilation (blood vessels opening up) as your body warms up. This increased blood flow helps flush out metabolic waste products like lactic acid which contribute to muscle soreness when they accumulate [3]. By promoting the removal of these waste products, cold water immersion may accelerate the recovery process.
Improved circulation
Our circulatory system acts like a complex network of highways, transporting oxygen, nutrients, and waste products throughout the body. Cold water immersion has the potential to improve circulation in several ways, thanks to its influence on blood vessels and blood flow.
When you hit the cold water, your body’s "fight-or-flight" mode is triggered. This survival mechanism activates the release of adrenaline and other stress hormones. These hormones cause blood vessels to constrict, particularly those closer to the skin's surface. This initial constriction helps to prioritise blood flow to vital organs like the heart, lungs, and brain, ensuring they have the oxygen and nutrients they need to keep you functioning optimally.
As your body continues to work to maintain core temperature, it triggers vasodilation, the widening of blood vessels. This rapid dilation increases blood flow throughout the body, including the extremities that were initially restricted [4]. The surge in blood flow carries fresh oxygen and nutrients to your tissues, promoting cellular health and improving the efficiency of waste removal.
The circulatory benefits of cold water immersion may extend beyond the immediate response. Some research suggests that regular cold water exposure can lead to long-term adaptations in the cardiovascular system. These adaptations could include improved blood vessel elasticity and a reduced risk of blood vessel constriction (vasoconstriction), both of which can contribute to better overall circulation [5].
Mood boost and mental health
Cold water immersion isn't just about physical benefits. It also holds the key to a brighter mood and a calmer mind. While anecdotal evidence abounds about the mood-lifting effects of a cold plunge, science is catching up.
When you hit the cold water, your body’s sympathetic nervous system goes into "fight-or-flight" mode, triggering the release of adrenaline and other stress hormones. But alongside these comes a surge of endorphins, the body's natural feel-good chemicals including dopamine, a reward molecule designed to make us want to do it again. Endorphins bind to receptors in your brain, creating a sense of euphoria. This endorphin rush is similar to the "runner's high" experienced during exercise, leaving you feeling more positive, and energised yet calm after dipping.
Immune system support
Some studies suggest cold water exposure might stimulate the production of white blood cells, which fight infection. This benefit gained popularity when a 2016 Dutch study found that users of daily cold showers showed a reduction in self-reported sickness. Since then, there have been numerous studies showing that cold exposure, typically in winter ice swimmers, increases the plasma levels of several different immune cells. Quite simply, more immune cells in your blood is generally a good thing.
Wim Hof and the Wim Hof Method (WHM) are perhaps now increasingly cited in terms of pushing the boundaries of our innate ability to control our immune system, something previously understood to be autonomic, beyond our control [6]. WHM combines DCE with breathwork and mindset training. In the most famous study of the WHM, subjects who trained for only 4 days were able to suppress their primary (innate) immune response to a bacterial endotoxin that was injected directly into their bodies. [7]
Sharper focus and increased willpower
Cold water exposure activates the sympathetic nervous system. This activation leads to a surge of noradrenaline and adrenaline, hormones that sharpen focus, improve reaction times, and enhance alertness, desire, and drive. Studies have shown that cold exposure can improve cognitive performance on tasks requiring sustained attention and working memory [8]. Wim Hof suggests it strengthens willpower (or resilience) by requiring mental discipline to overcome the initial discomfort. Regularly pushing yourself through the short-term challenge of cold water immersion can translate to better self-control and stress management in other areas of life [9].
Improved skin health
Cold water immersion may tighten pores and improve circulation, potentially leading to a healthier-looking complexion. When your body is submerged in cold water, blood vessels constrict, directing blood flow toward your core to maintain your internal temperature. As your body warms up again, blood vessels dilate, increasing circulation throughout your body, including your skin. This improved circulation can deliver more oxygen and nutrients to your skin cells, potentially promoting a radiant glow [10]. Anecdotal evidence suggests cold water immersion may also be beneficial for conditions like eczema and psoriasis. Some studies have shown that cold water therapy can reduce inflammation and itching associated with these conditions, although more research is needed to confirm its effectiveness [11].
Pain relief
Cold water immersion triggers the release of endorphins, the body's natural painkillers, which can help block pain signals from reaching the brain. Cold water can also numb nerve endings, offering temporary relief from chronic pain. The cold constricts blood vessels, reducing inflammation and swelling around an injured area, further contributing to pain relief. Studies have shown promise in using cold water immersion for pain management after surgery and for conditions like arthritis by decreasing inflammatory signalling molecules. In healthy people, five days of cold exposure decreased a pro-inflammatory protein called IL-2, the inflammatory E2 series of prostaglandins, but increased an anti-inflammatory protein called IL-10 [12].
Resilience building
Resilience is the ability to resist quitting or escaping by virtue of willpower - a top-down control over our body and resisting the reflex to jump out. The more we learn to manage the flood of noradrenaline and adrenaline and the feelings they evoke, the more we build resilience through improved willpower— useful for life outside of the ice bath or cold shower.
When you immerse in cold water up to the top of your neck you activate your vagus nerve. This nerve is the key component of your ‘parasympathetic nervous system’. It leads the “rest and digest” functions of the body such as stimulating saliva, slowing the heart rate, and stimulating digestion in the stomach and intestines as well as controlling your immune response and mood.
In a stressed state, our sympathetic nervous system is activated, and when stimulated, the vagus nerve leading to the parasympathetic nervous system counteracts that stress. Cold water immersion is a non-invasive way to activate the vagus nerve. Once you enter the water, it helps slow down your breathing and heart rate and switches you into a state referred to as ‘parasympathetic mode’, more commonly known as “rest-and-digest”.
We can also use this to influence our mental and emotional health. We know that prolonged, chronic stress causes chemical changes in the brain, presenting as anxiety and depression. Counteracting it by stimulating the vagus nerve with cold water therapy, is now understood to help improve these conditions.
Enhanced metabolic rate and fat burning
The body burns extra calories to maintain core temperature during cold water immersion. This process, called thermogenesis, involves breaking down brown tissue to generate heat. Brown fat is metabolically active and burns calories for energy. While the exact calorie-burning increase from cold water immersion is likely modest, it offers a boost to your metabolism and can contribute to weight management efforts when combined with a healthy diet and exercise routine [13].
Good for brain health
When your body is exposed to the cold, the cold shock releases a protein called RBM3: RNA Binding Motif 3 [14]. These proteins are directly linked to the regeneration of synapses in the human brain. Synapses are gaps between neurons through which our neurons communicate, and are responsible for normal brain function and how we form memories.
Found in the human heart, liver, skeletal muscle, and brain tissue, RBM3 can stimulate damaged or degenerated synapses. And, the more of this cold shock protein there is in your brain, the better the effect. While synapses can be damaged and disappear, especially as we age, studies have revealed that RBM3 interacts with neurons where they connect to synapses and boost their productivity [15]. RBM3 has been shown to not only repair and regenerate synapses but also rebuild neurons, preventing cognitive decline. This protective effect for both neurons and synapses has been demonstrated in multiple animal studies where RBM3 is in play [16].
Remember:
While these benefits are promising, research on some is ongoing. Cold water immersion is not a one-size-fits-all cure. Listen to your body and consult your doctor before starting your practice.
Explore our journal to explore more topics on cold water immersion
[1] Mohr, A. R., Stapleton, D. A., Webb, O. L., & Cameron-Smith, D. (2014). Cold water immersion for preventing and treating muscle soreness after exercise. https://www.cochrane.org/CD008262/MUSKINJ_cold-water-immersion-for-preventing-and-treating-muscle-soreness-after-exercise
[2] Bleakley, J. R., Costello, J. T., Paine, M. T., & McDonough, S. M. (2012). The effect of cold water immersion on inflammation and pain following intense exercise: a systematic review with meta-analysis. https://pubmed.ncbi.nlm.nih.gov/36399666/
[3] Cheung, K. S., Hume, P. A., & Maxwell, L. (2012). Can cold water immersion reduce DOMS and improve recovery after exercise? https://www.sciencedirect.com/science/article/abs/pii/S1466853X14000030[4] National Institutes of Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3189534/
[5] National Institutes of Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3189534/
[6]Wim Hof, regulation of autonomic function during cold exposure: https://pubmed.ncbi.nlm.nih.gov/29438845/
[7] Wim Hof Method: https://www.wimhofmethod.com/practice-the-method
[8] National Institutes of Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8616549/
[9] Wim Hof Method: https://www.wimhofmethod.com/
[10] International Journal of Dermatology: https://pubmed.ncbi.nlm.nih.gov/36832402/
[11] National Eczema Association
[12] Arthritis https://www.mdpi.com/2073-4409/9/4/880
[13] National Institutes of Health: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8616549/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC86165
[14] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6168273/