Benefits of Cold Water Therapy (According to Scientific Research)
Ok, so here’s a summary of the key research into the benefits of cold water therapy that convinced me to try it in the first place.| Benefit | What does the science say? | Further reading |
|---|---|---|
| Clears the mind | Activates the sympathetic nervous system, increasing alertness and sharpening mental clarity. | British Journal of Sports Medicine |
| Handles stress better | Regular cold exposure adapts hormonal stress responses, reducing cortisol spikes. | Scandinavian Journal of Clinical and Laboratory Investigation |
| Boosts mood | Cold exposure triggers noradrenaline release, lifting mood and alleviating depressive symptoms. | Medical Hypotheses |
| Strengthens immune response | Cold exposure activates the immune system, increasing white blood cell production. | PNAS Study |
| Improves circulation | Cold causes blood vessels to constrict and dilate, improving vascular tone and blood flow. | International Journal of Circumpolar Health |
| Enhances sleep and recovery | Core temperature drop post-exposure promotes better sleep quality. | General sleep physiology research |
| Fires up metabolism | Cold activates brown fat, increasing energy expenditure. | New England Journal of Medicine |
| Reduces muscle fatigue | Cold water immersion decreases muscle damage markers and speeds recovery post-exercise. | Journal of Strength and Conditioning Research |
1. Clears the Mind
The first few seconds in cold water leave no room for distractions. Your body demands immediate focus as you concentrate essentially on just regulating your breathing and trying to stop your body from thinking it is dying. Well, that’s my experience anyway.
This “forced mindfulness” isn’t just anecdotal though. Research suggests that cold exposure activates the sympathetic nervous system, increasing alertness and sharpening mental clarity.
A study published in the British Journal of Sports Medicine found that cold immersion significantly impacts the nervous system, creating a sense of heightened awareness.Regardless of the time of day I dip, I do feel a sense of mental clarity when I get out – usually lasting for hours.Some days I dip in the morning, but if the school run is a bit chaotic or I don’t have time in the morning for other reasons, I’ll dip in the evening. I like both for different reasons. But the one thing that is the same regardless of the time of day I take my plunge is that sense of clarity. It’s hard to explain without experiencing.The science said I could expect it and I’m definitely personally experiencing that.Cold Water Therapy and Stress Reduction
I’ve personally had a very up and down relationship with stress. A number of years ago I found I had ludicrously high cortisol levels causing me all sorts of physical symptoms. I took up things like hiking, started working out more, adapted my diet, spent more time outside and worked hard to improve my work life synergy.
It’s been years and I’ve now got the best handle on stress I think I’ve ever had. But I’m always keen to try anything that science claims can help regulate it.
Plunging into cold water trains your nervous system to handle stress more calmly over time. Cold exposure acts as a mild stressor, teaching your body how to stay composed under pressure.
Research in the Scandinavian Journal of Clinical and Laboratory Investigation showed that regular cold exposure leads to adaptive changes in the hormonal stress response, reducing cortisol spikes. Over time, that means greater resilience — both in and out of the water.
Now, it’s hard to say whether I’m experiencing this. It’s the sort of benefit that it takes time to experience I think and I’m already handling stress pretty well. So I can’t say for sure whether it matches my experience yet. But the research is certainly compelling.
Cold Water Therapy Boosts Your Mood
On the whole, I’m incredibly lucky with my mental health so far. Save a period of intense stress, I’ve been typically fortunate. But we all suffer the odd bout of low mood.
A 2008 study published in Medical Hypotheses suggested that cold showers can stimulate the brain’s “blue spot,” which is the primary source of noradrenaline (a chemical that helps to alleviate depression).
While the research is still emerging and pretty new and lots of reports of this are anecdotal rather than rooted in science, many regular cold water swimmers report improved moods, increased energy, and even reduced symptoms of anxiety after committing to daily dips.
For me, I’m finding that if I plunge in the morning I feel energised and in a good mood through the day and if I plunge in the evening I feel relaxed and incredibly chilled out in the evening.
I’m keen to see what impact this might have on moods during periods of high stress or worry too though and I’ll report back on that in the future.
Cold Water Therapy Can Improve Your Immune Response
Getting cold might actually help you stay well. A groundbreaking study in PNAS found that cold exposure, combined with breathing techniques, helped participants activate their immune systems and control inflammation.
Separately, other studies suggest that regular brief exposure to cold can increase white blood cell count, enhancing the body’s natural defence mechanisms. It’s not a cure-all, but it’s a powerful boost for your immune health.
Now I don’t think this is the sort of thing I can personally comment on. I have been perfectly well and healthy over the last 3 weeks but that’s not uncommon.
Since a bout of sepsis in 2019 I’ve suffered recurring infections – most recently in August 2024 when I got another (milder) bout of sepsis.
I’ve been well since August last year. But I’m eating well, exercising more and supplementing too. So I wouldn’t ever be able to say that being well is related to cold water therapy. But I’m more than convinced by the science here and always happy to do whatever I possibly can to keep my immune system in the best shape possible.
Cold Water Plunging Improves Circulation
Cold water forces your blood vessels to constrict and then dilate, which helps improve vascular tone and blood flow. Regular exposure to cold water trains your circulatory system to become more efficient.
Winter swimmers often report warmer extremities over time and reduced symptoms of conditions like Raynaud’s. While large-scale studies are still developing, early research points to real circulation benefits.
I don’t personally suffer from circulatory issues so this isn’t the most compelling of reasons for me to endure a shivery dip every day! But I’m always up for anything natural that offers any sort of long term health benefits, truth be told.
Cold Water Therapy and Sleep
This is one I can absolutely report benefitting from personally. My Garmin is reporting improved sleep quality scores and I am finding it easier to fall asleep.
After a cold water dip, the body’s core temperature drops which is a trigger for the body’s natural sleep signals. Many who take part in evening dips report deeper, more restorative sleep. And on the days I have not been able to do my dips in the morning, I’ve dipped in the evening instead and definitely found this to result in a more relaxed evening and found it easier to fall asleep.
So much so, I am considering moving all of my dips to the evening.
While direct scientific studies are still limited and emerging, general sleep research supports the idea that a cooler core body temperature facilitates better sleep onset and quality.
Cold Water Therapy and Your Metabollism
With the help of a high protein diet and a lot of exercise, I’ve been losing weight over the last few months and a rate I’m really pleased with. But if someone tells me that something might give my metabolism a kick up the backside to get moving faster, I’m probably going to have a go.
Of course I can’t personally say over the last 3 weeks that cold water plunging has helped me lose fat. I’ve been losing fat at a steady rate for 6 months now.
But the science makes for interesting reading.
Cold exposure activates brown adipose tissue — a type of “good” fat that burns energy to produce heat. A study published in the New England Journal of Medicine confirmed that even mild cold exposure can stimulate brown fat activity, boosting your metabolism.
While it’s not a magic bullet for weight loss, regular cold water therapy can slightly increase daily energy expenditure and contribute to better metabolic rate.
Cold Water Therapy and Muscle Fatigue
We’ve known for years that cold water therapy is good for post exercise muscle recovery. So this is by no means new.
Cold water immersion is used by athletes for a reason – it speeds up recovery by reducing muscle fatigue. Studies have shown that immersing in cold water after intense exercise decreases muscle soreness and lowers levels of muscle damage markers like creatine kinase.
I do a lot of hiking, I play football and am generally very active. So anything that helps to stave off those muscle pains (the ones that come from the result of me trying to get my 40 year old body to do all the things it did when it was 20) is good by me.
I’ve absolutely found that after high activity days in particular, I’m much less likely to suffer muscle soreness the next day if I’ve cold water plunged. This has been noticeable for me.
A meta analysis in the Journal of Strength and Conditioning Research concluded that cold water immersion effectively reduces perceptions of fatigue and accelerates muscular recovery.
I’m sticking with it
Final Thoughts
Cold water therapy isn’t for everyone and it’s important to approach it safely. But for those willing to embrace a little discomfort, the rewards can be pretty profound indeed. From sharper minds to stronger bodies and better moods, my own experience so far has been compelling enough to make me stick with it despite the discomfort.
Whether you start with a 30 second cold shower or venture into wild winter swims, the science suggests that the chill might just be worth it.
Now it’s not suitable for everyone. Some people with heart disease, hypertension or those at risk of strokes, for example, may not be able to take part safely. So if you’re in those brackets or have other health conditions, it is definitely worth speaking to your doctor before taking the plunge!
Sources & Further Reading
Bleakley CM, Davison GW. “What is the biochemical and physiological rationale for using cold-water immersion in sports recovery?” British Journal of Sports Medicine, 2010.
Higgins TR, Greene DA, Baker MK. “Effects of Cold Water Immersion and Contrast Water Therapy for Recovery from Team Sport: A Systematic Review and Meta-Analysis.” Journal of Strength and Conditioning Research, 2017.
Shevchuk NA. “Adapted cold shower as a potential treatment for depression.” Medical Hypotheses, 2008.
van Marken Lichtenbelt WD, et al. “Cold-activated brown adipose tissue in healthy men.” New England Journal of Medicine, 2009.
Kox M, et al. “Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans.” Proceedings of the National Academy of Sciences, 2014.
BBC Health. “Can cold water swimming help treat depression?” BBC News, 2018.
Westerlund T, et al. “The influence of winter swimming on psychological aspects of health.” International Journal of Circumpolar Health, 2003.
Higgins TR, Greene DA, Baker MK. “Effects of Cold Water Immersion and Contrast Water Therapy for Recovery from Team Sport: A Systematic Review and Meta-Analysis.” Journal of Strength and Conditioning Research, 2017.
