Updated: Oct 20, 2020
The use of cold water immersion (hydrotherapy) is probably as old as mankind. From the ancient Greek physician Hippocrates to the modern-day life coach Tony Robbins, many incredible people have accredited their physical fitness and mental sharpness to cold water exposure.
Is there any truth in it? Let’s put it to the test and see what science has to say about its effects on our body systems.
Respiratory system - A boost in lung function
We all know the feeling of gasping for air during a run, as if our lungs are too small. How do athletes even get enough air?
Training is of course a big part, but athletes also try natural therapies and extreme conditions that challenge their body to adapt. Cold water immersion is a common practice among athletes as it is linked to an increase in lung capacity, boosting subsequent sports performance (1).
Apart from professional athletes, cold water immersion also has benefits for some patients with respiratory diseases. For patients with chronic obstructive pulmonary disease (COPD), repeated cold water stimulations reduced their frequency and severity of infections (2). In children suffering from recurrent and asthmatic bronchitis, local cold procedures helped improve their condition while hot treatment had the opposite effect (3).
Nervous system - Sharpens your mind
Some people say a cold shower is like a triple shot coffee – it just sharpens the mind and pushes the body to get going. What happens in your brain after the temperature receptors on your skin sense a sudden cold exposure?
Cold exposure activates some parts of the brain that enhance sensory and motor functions (4). It increases the blood level of neurotransmitters associated with excitement – endorphin and noradrenaline. These changes in the brain could be why cold exposure is so effective in reducing fatigue.
There is also evidence that cold exposure has beneficial effects to people with mental illnesses. For example, cold shower might have antipsychotic and antidepressive effect because it works like a mild electroshock to the sensory part in the brain (5).
Afterall, there is a reason why a cold shower instantly sharpens your mind. Just like how caffeine stimulates the brain, cold water does it naturally!
Immune system - Help your immune cells fight
You might be thinking: I’m not taking a cold plunge, it will make me sick!
Guess what, people who incorporate cold showers in their daily routine like Tony Robbins are actually much healthier. One study reported that people who take cold showers call in sick 29% less often than those who take hot showers (6)!
Our immune system is what keeps us safe – White blood cells, T-cells and Natural killer cells are brave soldiers that keep the bad bugs away. Someone with a weak immune system catches a cold easily, but someone with strong immunity seems to never get sick! This difference becomes particularly obvious after 25 or 30, when years of habits start to show a consequence.
It turns out that cold exposure increases the number of immune cells and boosts their activity (7). So a cold shower is not only a training for you, but also for all the soldier cells inside of you!
If you can keep up the habit, the long-term immune benefits can be huge! Repeated daily cold exposure could even increase the blood levels of anti-tumor factors such as tumor necrosis factor-α (TNF-α) (8). This means that your body will have a higher antitumor immunity and be less vulnerable to nasty cancer.
Hormonal system - More energized, less stressed
Hormones are messengers in the body that are important for a number of functions and feelings – stressed, energized, happy, scared and so on.
During cold exposure, the levels of hormones in the body change dramatically. You can get increased levels of:
Adrenocorticotropic hormone (ACTH)
These hormones give you a ‘High’ feeling, as it makes you more energized and bold9.
On the other hand, cold exposure can decrease the levels of cortisol – the stress hormone (10), which is why some athletes like to take a cold steam bath before their games. So next time you feel stressed out, why not try a cold shower to calm down?
In summary, making cold showers and wild swims part of your daily routine does seem like a good idea that is backed up with evidence. Even a quick exposure can have noticeable benefits. If you can keep it up, you will reap bigger long-term health benefits.
Of course, there are also things to watch out for when you are just starting out, check out this blog before you take the plunge! Although cold showers may help with some conditions, you should not use it to replace your treatment without consulting a doctor.
Bleakley CM, Davison GW. What is the biochemical and physiological rationale for using cold-water immersion in sports recovery? A systematic review. Br J Sports Med. 2010;44:179–87.
Goedsche K, Förster M, Kroegel C, Uhlemann C. Repeated cold water stimulations (hydrotherapy according to Kneipp) in patients with COPD. Forsch Komplementmed. 2007;14:158–66.
Iarosh AM, Kurch TK. The effect of cold exposure on the respiratory function in children suffering from inflammatory lung diseases. Vopr Kurortol Fizioter Lech Fiz Kult. 1995;1:9–11.
Shevchuk NA. Possible use of repeated cold stress for reducing fatigue in chronic fatigue syndrome: A hypothesis. Behav Brain Funct. 2007;3:55.
Shevchuk NA. Hydrotherapy as a possible neuroleptic and sedative treatment. Med Hypotheses. 2008;70:230–8.
Buijze G, Sierevelt I, Heijden BCJM, Dijkgraaf MG, Frings-Dresen MHW. The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial. PLoS One. 2016;11:9.
Brenner IK, Castellani JW, Gabaree C, Young AJ, Zamecnik J, Shephard RJ, et al. Immune changes in humans during cold exposure: Effects of prior heating and exercise. J Appl Physiol. 1999;87:699–710.
Shevchuk NA, Radoja S. Possible stimulation of anti-tumor immunity using repeated cold stress: A hypothesis. Infect Agent Cancer. 2007;2:20.
Mooventhan A, Nivethitha L. Scientific evidence-based effects of hydrotherapy on various systems of the body. N Am J Med Sci. 2014; 6:5.
Panov SF, Pleshakov AA. Effect of steam bath on gastric secretion and some endocrine changes of athlete-fighters. Fiziol Cheloveka. 2011;37:92–9.
Written by Yunan Ye commissioned by ICEWIM.
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