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Benefits of cold-water swimming: the facts part 1

Updated: Apr 5, 2022

Cold-water swimming is good for mental health

This is perhaps the most researched and the most commonly cited benefit to cold-water swimming.

Cold-water swimming can be separated out into five different elements, each of which is suggested to be helpful for mental health:

(i) Exercise in general

(ii) Swimming in particular

(iii) Being in nature

(iv) Getting very cold

(v) Company

(i) Exercise in general

A report that looks through on a number of studies that have found that exercise has benefits to mental health found no conclusion as to which exercise types are most beneficial. One study cited suggests that three to five sessions of up to 45 minutes each week was effective for reducing depression – but noted that excessive exercising can have a negative effect. Team sports appear to be particularly positive; this could be because of the social aspect – more on that in point (iv). But are people with better mental health more likely to exercise? Perhaps, but in the UK, physical activity is recommended to treat mild to moderate depression and any ‘pleasant and enjoyable’ physical activity is beneficial – this need not be sport; gardening, for example, is included.

A lot of people believe that cold-water swimming could not possibly be a ‘pleasant and enjoyable’ physical activity. They’re perhaps right that it’s not always ‘pleasant’ – but it is enjoyable… if you enjoy that sort of thing! Sadly, we don’t have the time for three or more river swims a week but most of us pool-swim, walk, run or cycle in-between swims, finding that the most ‘pleasant and enjoyable’ of our activities is the river swim.

(ii) Swimming in particular

The previous section suggested that no particular exercise was especially beneficial to mental health but can we at least be sure that swimming is an exercise that helps? One study has concluded that yes, it is – in rats…

In 2018, Swim England commissioned a You Gov poll that found that, like the rats, 1.4 million human adults felt that pool-swimming helped their mental health.

(iii) Being in nature

Exposure to the natural environment has mental health benefits. For the faint-hearted, watching it on TV, especially on a big screen, helps – but not as much as being in the real outdoor world. Interestingly, environments with water are the most popular, although that doesn’t necessarily mean that everyone who sees water wants to get in it…

(vi) Getting very cold

This is the focus of the research in the BBC documentary ‘The Doctor Who Gave Up Drugs’ and as the most transformative part of cold-water swimming (in our experience), it seems plausible that it is the most significant aspect to any benefits cold-water swimming has on mental health.

In the documentary, Dr Chris van Tulleken began a treatment to help a 24-year-old-woman who had been on anti-depressants since the age of 17 to come off her medication. His prescription? Cold water swims. In the TV programme, we learn that, in response to the cold-water swims, the patient was decreasing her dosage of antidepressants. A follow-up paper published in the British Medical Journal, reports that she was able to come off the drugs completely and one year on, was still not taking them. In this study of one, the results are conclusive – but, of course, it means very little until a wider study is completed.

Van Tulleken and his colleagues explain that our bodies respond to cold water in a similar way to an anxiety attack. As we cool, the body enters a state of shock which floods the body with stress hormones and once this has passed, we experience a ‘high’ (ah! love that high!). The theory is that if we immerse ourselves in cold water often enough, we condition our bodies to deal with the stress response.

The article acknowledges the variables that could influence this result: the natural environment, exercise, etc. – also the sense of achievement, which is definitely part of the experience in the winter and can be very uplifting. The article considers also the chemical changes induced by the post-swim ‘high’ and the stimulation of the vagus nerve* caused by immersing the face in cold water.

(v) Company

Most people who swim in open water, swim in a group – if for no other reason than for safety. Not only does friendship benefit mental health, but people who feel supported by friends tend to live longer – which is great, as it means we can get in more river swims. There are people content to get in cold water by themselves (e.g. The Lone Swimmer) – and not necessarily to exercise (e.g. Wim Hof); they’re obviously getting plenty of other benefits from their cold-water swimming.

Being in our particular swim pod seems to involve much laughter and laughter is good for mental health. One theory is that laughter relaxes the body and releases our natural feel-good drug: endorphins. Another suggestion is that it decreases stress-making hormones found in the blood so mitigates the effects of stress.


There is some indication that any one of these aspects of cold-water swimming – exercise, swimming, nature, cold water, company – has mental health benefits. As cold-water swimming includes all of them, can we conclude that it must be very good for mental health?!

* The vagus nerve runs from the brain, through the face to the thorax and abdomen. Various forms of non-invasive vagus nerve stimulation treatments are considered worthy of investigation as treatments for epilepsy, depression, primary headaches. There may also be a relationship between depression, inflammation, metabolic syndrome, and heart disease and the vagus nerve, and articles suggest that stimulation of the vagus nerve may offer favourable effects on cardiovascular, cerebrovascular, metabolic, and other physiological biomarkers associated with depression morbidity and mortality.


Elbe, A.M., Lyhne, S.N., Madsen, E.E., Krustrup, P. (2019): ‘Is regular physical activity a key to mental health? Commentary on "Association between physical exercise and mental health in 1.2 million individuals in the USA between 2011 and 2015: A cross-sectional study"’, by Chekroud et al., published in Lancet Psychiatry. J Sport Health Sci.;8(1):6–7.

Hof, W. (site accessed April 2020)

Howland R. H. (2014). Vagus Nerve Stimulation. Current behavioral neuroscience reports, 1(2), 64–73.

Liu, W., Sheng, H., Xu, Y., Liu, Y., Lu, J., Ni, X. (2013) ‘Swimming exercise ameliorates depression-like behavior in chronically stressed rats: Relevant to proinflammatory cytokines and IDO activation’. Behavioural Brain Research, 242: 110–116.

The Lone Swimmer (site accessed April 2020)

Pearson, D. G. & Craig, T. (2014) ‘The great outdoors? Exploring the mental health benefits of natural environments’ Frontiers in Psychology 5: 1178

Pickett, K., Kendrick, T., & Yardley, L. (2017). “A forward movement into life”: A qualitative study of how, why and when physical activity may benefit depression. Mental Health and Physical Activity, 12, 100–109.

Roderick, M. C. (2014). Virtue development through team sports to address mild-to-moderate depression (Order No. 3631381). Available from ProQuest Dissertations & Theses Global. (1566173464).

van Tulleken, C., Tipton, M., Massey, H., et al. (2018): ‘Open water swimming as a treatment for major depressive disorder’ Case Reports bcr-2018-225007.

White, M., Smith, A., Humphryes, K., Pahl, S., Snelling, D., & Depledge, M. (2010) ‘Blue space: The importance of water for preference, affect, and restorativeness ratings of natural and built scenes’ Journal of Environmental Psychology 30 (4): 482–493.

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