7 science-backed benefits of taking a cold shower

by Inessa Team

Are cold showers good for you? Celebrities seem to think so. Fearne Cotton endures an icy cold shower each day as a way to boost her energy and her mood. Kim Kardashian, Harry Styles and Kendall Jenner are all said to be fans of ice baths. The BBC’s Dr Michael Mosley is so convinced by evidence linking cold water immersion to improved immunity and heart health, he’s now a regular cold water swimmer.

Whether it’s a dip in the sea, a dunk in an ice bath or just a quick burst of chilly water at the end of a warm shower, cold water therapy has taken the wellbeing industry by storm. Its proponents believe it’s beneficial as it can help harness the body’s natural response to stress.

While repeated exposure to stress in high doses can clearly be toxic, lower doses encourage beneficial adaptations that actually enhance health. In fact, a growing body of research suggests that the short-term stress of cold water immersion triggers hormesis, a biological response that triggers a raft of benefits that can boost circulation, reduce muscle inflammation and improve mood. Other examples of hormetic experiences include intermittent fasting and intense exercise, such as HIIT.

Whether through a cold shower or ice bath, immersing yourself in cold water causes your heart rate to increase and your blood vessels to change shape - some decrease in size, while others double, and all in a matter of seconds. Dr Mosley calls this, “an orchestra of responses that put your body into gear for survival – all the while, giving you quite the thrill!”

And while the practice has only recently been embraced by celebrities, it appears our ancestors were well ahead of us when it came to using cold water for health purposes. The Romans used a combination of steam rooms, hot tubs, and cold baths, while Victorian doctors prescribed cold baths for both bruises and hysteria. Traditional Chinese medicine (TCM) has a long tradition in promoting health by taking a dip in pools, rivers or lakes where the water temperature is usually below 20℃.

So were the health practitioners of the past really on to something? We’ve delved into the science behind cold showers to find out if braving the chill is really worth the morning goosebumps...

1. Cold showers can boost your mood

A morning blast of cold water is undoubtedly invigorating - and you’ll certainly feel happier once it’s over. But could lifting a low mood be one of the biggest benefits of cold showers? That’s what researchers at the Virginia Commonwealth University School of Medicine aimed to find out_[1].

They hypothosised that the skin has a high density of cold receptors. When these are stimulated, it sends strong electrical impulses to your brain to trigger the release of mood-regulating neurotransmitters like endorphins (the same chemicals that create the famous “runner’s high”).

They showed that cold hydrotherapy “can relieve depressive symptoms rather effectively”, with no noticeable side effects.

A narrative study on the benefits of cold water therapy as a treatment for low mood was carried out on a 24-year old patient with depression and anxiety. She had previously not responded to conventional treatment and was searching for alternative therapies_[2].

She started a weekly programme involving cold water swimming, which resulted in an immediate improvement in mood after each swim and a sustained and gradual reduction in the symptoms of depression overall.

The intervention ultimately led to a reduction in the patient’s medication use and, after one year of therapy with cold water swimming, she was medication-free.

2. Cold showers can make you feel more alert

If you were to ask a hundred people ‘what do cold showers do?’ chances are the answer ‘they wake you up’ would feature highly.

There’s science to back this up. Turning down the dial in your morning shower stimulates catecholamines - hormones that the body produces in response to emotional or physical stress. This helps activate the sympathetic nervous system and increases the concentration of norepinephrine and β-endorphin so you’re ready to fire on all cylinders again.

It may also be a particularly effective (if short-lived) form of treatment if you suffer from sleep inertia - a prolonged feeling of disorientation when you wake up. Although studies on cold showers and sleep inertia are rare, a 2016 review of countermeasures to the disorder showed an immediate reduction in subjective sleepiness after a 20-minute nap when subjects washed their face in cold water. It postulated that a cold shower might be more effective than a quick face wash due to changes in overall body temperature, and noted more research was needed._[3]

3. Cold showers may improve blood sugar management

In Type 2 diabetes, the body doesn’t respond well to insulin and the level of sugar in the blood becomes too high. Left untreated, high blood sugar can lead to permanent damage to parts of the body like the kidneys, eyes, nerves and blood vessels. Figures from Diabetes UK show that almost 4.3 million people have Type 2 diabetes in the UK, and that there are an additional 850,000 living with the condition who are yet to be diagnosed.

Research has shown that combined lifestyle interventions - including diet, physical activity and sustained weight loss - can be effective in reducing the risk of type 2 diabetes by about 50%. Could cold water therapy also become a recommended treatment?

Several cold shower science studies have demonstrated that deliberate cold exposure will clear glucose from the bloodstream and improve insulin sensitivity. In a study that looked at the effects of cold water therapy on blood glucose control, swimming in cool water was found to hinder the development of type 2 diabetes and improve management of the condition, although the most beneficial effects were seen predominantly in the female swimmers.

In the field study, 30 cold water swimmers were examined for six months with regard to body composition and insulin sensitivity. For female swimmers with lower body fat percentage, there was an increased insulin sensitivity as well as a reduction in insulin secretion and resistance_[4].

So how does it work? Researchers from Canada attempted to find out. Their report, published in the medical journal Physiology of Thermal Therapy found that cold water exposure not only increases energy expenditure, but also aids whole body glucose and fatty acid utilization. Much of the metabolic effects were attributed to the effects of shivering on skeletal muscles, but they also discovered repeated exposures to cold can lower fasting glucose and insulin levels and improve dietary fatty acid handling_[5].

4. Cold showers can support your immunity

Submerging yourself in cold water to prevent a cold sounds counter-intuitive, but there is growing evidence that winter swimmers are more resistant to certain illnesses and infections. For example, cold water swimmers seem to have fewer upper respiratory tract infections_[6].

And the good news is that you may not even have to brave the local duck pond to reap the immunity benefits. One study has found a link between cold showers and boosted health, showing a 29% reduction in reported “sick days” at work for those who submitted themselves to the daily ritual_[7].

The benefits of a cold shower on the immune system have been studied widely. Cold water helps to boost the white blood cell count because the body is forced to react to changing conditions. Over time, your body becomes better at activating its defenses.

Research was carried out on 15 healthy men who had never been exposed to cold water swimming. They were studied for five consecutive months of winter swimming. Findings showed significant changes in hemoglobin concentration, the number of red blood cells, the hematocrit index and mean corpuscular volume of red blood cells and the percentage of monocytes and granulocytes after the winter swimming season. The obtained results may indicate positive adaptive changes in the antioxidant system of healthy winter-swimmers. These changes seem to increase the readiness of the human body to stress factors_[8].

Research has also found changes in uric acid and glutathione (antioxidant) levels during ice bathing. Further investigation demonstrated that the intensive voluntary short term cold exposure of winter swimmers produces oxidative stress, improving antioxidant adaptation_[9].

5. A cold shower can improve exercise recovery

Ever wondered why top athletes swear by an ice bath after long periods of exertion? Cold water helps constrict the blood vessels near the surface of your skin - a process known as vasoconstriction - diverting blood towards your core. This is said to reduce swelling and inflammation in the muscles, by drawing waste substances and lactic acid away.

Then, when the body begins to warm up again, vasodilation occurs, pumping fresh, warm blood around the tissues, bringing nutrients, oxygen, and aiding in recovery_[10].

6. A cold shower could help you build muscle

Need another reason to turn down the heat on your post-workout shower? It’s been suggested that swapping hot for cold water could help you see more muscle gains. Although further research is required into this particular cold shower benefit, a 2015 study found that cold water immersion attenuated long term gains in muscle mass and strength. It also blunted the activation of key proteins and satellite cells in skeletal muscle up to two days after strength exercise._[11]

7. Cold showers can help soothe inflammation

Chronic inflammation is at the root of many of the diseases that represent the leading cause of mortality worldwide, such as heart disease, diabetes, stroke and cancer. But, one particularly exciting area of research is looking at how cold habituation decreases inflammatory responses over time.

So how do cold showers reduce inflammation? It’s thought that cold exposure activates your sympathetic nervous system, lowering levels of the pro-inflammatory cytokines that contribute to chronic inflammation_[12].

Where to start

Ready to take the plunge and experience the health benefits of cold showers for yourself? Luckily you don’t have to head for the sea or take an ice bath to reap the benefits, as a shower that’s 21℃ or cooler is quite adequate. Start gradually by taking a warm to cold shower, alternating to cold for just a few seconds. Keep your breathing steady and, as you get used to the feeling (which isn’t pleasant at first!), you can gradually increase your time in the cold water.

Cold Showers FAQs

Still not sure whether you should join the chilly revolution? Here are some of the most frequently-asked questions on the science of cold showers to help you decide.

How long should a cold shower last?

The good thing about adding a cold shower ritual into your morning routine is that it only takes a matter of minutes to reap all the mental and physical health-boosting benefits.

After your normal shower, slowly turn the dial to cold until you start to feel uncomfortable. Stay underneath the cooler water for around two to three minutes. Then, the next time you have a shower, see if you can make it that little bit colder, and try to stay under it for a few seconds longer. There’s no need to overdo it (or get into full Wim Hof mode) to feel the benefit of a cold shower.

Is it good to have cold showers every day?

Unless you’re feeling under the weather, a cold shower is something you can do on a daily basis. Just ask Dwayne ‘the Rock’ Johnson, who has a cold shower to boost his metabolism in the morning, a warm shower after his daily workout and a hot shower before bed.

In fact, to reap the best benefits of cold showers, consistency is key. Incorporating cold showers into your daily routine takes strength and dedication, but it’s worth persevering with as proponents say the ritual is something they eventually start looking forward to.

Are cold showers suitable for everyone?

If you’re generally fit and well, taking cold showers shouldn’t have any negative effects beyond feeling uncomfortable or making you shiver. However, they’re not for everyone. Those who suffer from cold urticaria, a hive-like skin reaction to cold exposure, or Raynaud’s syndrome, which causes numbness in response to cold, should steer well clear. The same goes for those with heart disease, blood pressure problems or other related medical conditions, since a shock of cold may put added stress on the heart.

If you're feeling under the weather, have recently been in hospital, or are immunocompromised, this might be one wellness ritual you may wish to avoid.

Also, remember that taking cold showers should never be a substitute for medication or your doctor’s advice.

If you enjoyed this post, you may like to read “Healthy habits of successful people”.

References

https://pubmed.ncbi.nlm.nih.gov/17993252/
https://pubmed.ncbi.nlm.nih.gov/33276648/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5136610/
https://www.researchgate.net/publication/297894015_Cold_Water_Swimming_Beneficially_Modulates_Insulin_Sensitivity_in_Middle-Aged_Individuals
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5136610/
https://journals.physiology.org/doi/pdf/10.1152/japplphysiol.00934.2020
https://extremephysiolmed.biomedcentral.com/articles/10.1186/2046-7648-4-S1-A36
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5025014/
https://pubmed.ncbi.nlm.nih.gov/23514015/
https://pubmed.ncbi.nlm.nih.gov/10396606/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4706272/
https://pubmed.ncbi.nlm.nih.gov/26174323/
https://www.researchgate.net/publication/12580231_Adaptation_related_to_cytokines_in_man_Effects_of_regular_swimming_in_ice-cold_water