Cold showers, ice baths & winter swimming

On the main picture that’s me doing a cold water exposure, my special place where even during summer time the lake had water temperature 8°C (46.4 F), and the air temperature was 28 °C (82.4 F), the initial cold shock was real 🙂 ! 

While doing research for cold water therapy/cold water immersion/ice baths and winter swimming, I’ve read widely known amazing Wim Hof’s book, but at the same time I asked: “Is there any book based on science research which looked into the cold water therapy dangers and benefits ?” Thankfully to Dr. Susanna Søberg we can read her incredible book called “Winter Swimming: The Nordic Way Towards a Healthier and Happier Life” and check for ourselves. I will go through several topics in my article using her book as a guideline, please make sure you’ll buy her book and support her work the same way I did, most of the topics from the book are not covered in this article as there are too many of them, simply click on the picture at the end of this article.  

I’ve had “cold showers only approach” for several years now, meaning I literally shower only in cold water, no exceptions. Last year in 2022 I also started with ice baths, I installed an ice tub on our balcony and sometimes I went for cold water dip into the frozen lakes/rivers near by. But in regards to ice swimming I’m definitely a beginner who hopefully over the years will become a habituated winter swimmer. During last season I went for 2 minutes duration while doing cold water dip in the frozen lake or using ice tub on my balcony during winter months.


Give cold showers the same benefits as winter swimming/ice baths ?

There are two reasons why a cold shower cannot compare to winter swimming:
1) The first has to do with the seasons. Habituation to open water temperatures happens gradually and in parallel with seasonal changes. Just when you think you’ve become habituated to the water, the water and air temperature can change suddenly, and you experience a new round of the cold-shock response.
2) The second reason is physiological. In the shower, water hits the body in the form of drop- lets. The droplets mostly make contact with the upper body and are warmed by your skin as they run down your legs, sending mixed signals to your brain. In contrast, winter swimming is a whole-body cold-water immersion which triggers a response in the sympathetic nervous system as well as the diving response. Full immersion exerts hydrostatic pressure (which cold showers don’t) and stimulates baroreceptors (arterial and cardiopulmonary), causing an inhibition of the sympathetic nervous system and an increase in vagal tone. This will lower heart rate and blood pressure due to parasympathetic activation. The latter also controls cortisol and serotonin levels and might be partly responsible for the health benefits observed in winter swimmers. As the diving response isn’t activated during cold showers, the benefits are unlikely to be the same as with cold-water immersion.

BUT: In a clinical trial on cold showers which measured sick days for a period of ninety days researchers found that taking cold showers for thirty seconds for thirty days decreased sick leave from work.


Cold showers as habituation for winter swimming/ice baths ?

The answer is both yes and no. A study from 2005 looked into whether repeated cold showers could be a method of habituation for cold-water immersion. Researchers investigated the relationship between temperature change to the skin and the subjects’ breathing rate as an indication of habituation. Those subjects who took regular showers at 10°C (50°F) took fewer breaths than those who had showered using warmer water (15°C/59°F) when they went into cold-water tubs containing water at 10°C. This suggests that if the water temperature in the shower is the same as that of the seawater, you can habituate your body to cold water before you start winter swimming. But if the shower is just 5°C (9°F) warmer, you’ll experience a cold shock. That’s why I never switch between cold and hot water, I do always cold showers full blast ! 


How long and how often ? Morning or evening ?

Active winter swimmers swim on average twice a week(cold showers can be taken every day). If you are new to winter swimming, however, it can be an advantage to start in the afternoon or evening, because you are more sensitive to the cold in the morning. The core temperature of the body is lowest in the morning (36.5°C/97.7°F) and highest in the evening (37-37.5°C/98.6-99.5°F). Whether staying one, two, three or more minutes in cold water increases the health benefits or risks is not known. Furthermore, we do not yet know the health benefits or risks of winter swimming over many years, even if swimmers themselves are convinced that the icy water is beneficial. It takes between twenty seconds and a minute before the initial calmer phase sets in, where the skin approaches the same temperature as the water and the nerves are numbed by the pain-relieving effect of the endorphins and noradrenalin. It hurts a little less and the water feels less cold. The worst of the stress is over, which makes breathing calmer and more controlled. 


How cold the water should be ? When do we “start to feel it” ?

In terms of our perception of water temperature, there is a threshold of around 15°C (60°F), after which we experience the water as freezing cold.


Is it better to start in autumn/spring or in the winter ?

If you are healthy and have no heart condition, bear in mind that you can start at any time of the year. For some starting in spring or autumn is better as the water is not yet that cold, but bear in mind that the water temperature and air temperature difference is greater in autumn and spring, therefore for some it is more challenging to start in those times. During winter months air temperature and water temperature difference is not that great, sometimes they are identical therefore some prefer to start during winter months as the cold shock might be less intense, but water will be much colder. The conclusion is to start, go and do it ! As with everything else that’s challenging for our bodies and minds, there will never be a perfect time for start.

Don’t worry if as a beginner you still feel the chill several hours after your plunge. This is the afterdrop, a normal physiological reaction to cold immersion. It will decrease once you get used to the cold.


White Fat vs. Muscle

Winter swimming performance also depends on your fat and muscle stores. If you want to learn to swim in cold water, it’s a good idea to build up muscle mass. (As I always say, it is not one thing that helps you being in a great shape, exercising and building muscle mass is part of the process as well). When we get cold, our sympathetic nervous system is activated and our muscles begin to shiver to produce heat. Muscle cells rapidly absorb oxygen and sugar from the bloodstream due to the store’s supply of blood to the tissue, which thereby creates heat. But isn’t it white fat that keeps us warm? Partly, yes, but muscles are better at producing heat, while white fat acts more as insulation. White fat is stored around our inner organs, and on our abdomen, hips, buttocks and thighs. Unlike muscle, white fat has a poor supply of blood and, accordingly, poor oxygen uptake and heat production. It takes a relatively long time for a white-fat cell to be activated compared to a muscle cell. White fat stores energy, as opposed to muscle, which can burn energy quickly. So, it doesn’t help your swimming performance to have little lean muscle mass and lots of white fat. In fact, a large amount of muscle mass combined with a medium amount of white fat (that is to say, something in the normal body fat percentage) can be the sweet spot.



Brown fat, a relatively unknown but very important organ.

When the brown-fat cell is activated, the mitochondria split the fat inside the cell with the production of adenosine
triphosphate (ATP) – a molecule that carries energy within cells – and the energy is released directly as heat in the body. To create that energy, the brown-fat cells pull sugar and fat from the bloodstream as fuel. Brown fat is unique because it can be activated to burn energy and produce heat in a process that goes like this: cold temperatures are detected on the skin, which signals via nerves to the brain. Noradrenalin is released and activates the brown-fat cells to perform a mechanism called thermogenesis – heat production. Until fifteen or twenty years ago, brown fat was thought to be a merely insignificant tissue in adults. Scientists believed that it existed in large proportions only in newborns, where it was important for maintaining a sufficiently high core temperature, as muscle shivering is not developed in the infant state. The question then arises: What is the purpose of brown fat in adults? It must
have important functions; otherwise, evolutionarily, we would have lost it. I stop here as there is an entire section dedicated to brown fat in the book and I really encourage you to read it.


Your 1st swim/ice bath !

  • Never swim alone.
  • Warm up your muscles before you go in, with some star jumps or a quick
  • Keep your robe on all the way to the steps of the jetty. Walk slowly, as
    the jetty and steps can be slippery.
  • Never dive into cold water headfirst.
  • Breathe calmly when sitting or swimming in the water – cold water can
    give you temporary shortness of breath – therefore exhale completely and
    then go in, breathing deeply and calmly.
  • If there are waves, hold on to a rope or railing.
  • Go in purposefully until the water covers your shoulders.
  • Take only a short swim of five to ten seconds the first few times.
  • Count aloud to occupy your brain in the water. (You can increase your
    time as you get more and more comfortable with the cold. Most winter
    swimmers increase by twenty to forty seconds per session.) Then get out of
    the water and put your bathrobe on. Put your hands in your armpits to
    warm them up and get over the worst of the cold shock.
  • Put on warm clothes and drink plenty of tea or another hot drink.
  • If you go directly from the sauna, let your body cool down a bit in the
    wind before you get into the water – this helps you avoid the worst of the
    cold shock.
  • Under no circumstances go into the water if you feel ill or are under
    the influence of alcohol.


How the cold-shock response works:

When you enter the water, everything kicks in, and involuntarily you begin to gasp for air and to hyperventilate, especially if you’re not used to swimming in the cold. The brain immediately perceives the icy water as dangerous. The shock triggers the stress response in which the body focuses on surviving and protecting its most vital organs. Peripheral blood vessels in fingers, toes, arms, legs and skin contract quickly. The blood flows towards the core to maintain heat, oxygen and functions in the vital organs. The heart rate drops due to the diving response and the heart no longer needs to pump blood all the way to the small blood vessels in the extremities, which lowers the blood pressure. Studies in the acute cardiovascular response of cold-water immersion show a small increase in blood pressure immediately before unhabituated winter swimmers go into the water. This is probably due to excitement and nervousness over the impending cold rush.


Danger: Hypothermia as core temperature decreases in cold water

As the body cools, it gradually shuts down vital bodily functions. Untrained winter swimmers can retain mobility for between ten and thirteen minutes in water below 5 °C (41 °F). At these low temperatures, it is only cold-habituated and trained ice swimmers who can stay in the water for longer. Being in the water for longer than thirty minutes can lead to hypothermia, i.e. having a core body temperature of less than 35°C (95°F), which can cause vascular and nerve damage and lead to serious injury or even death.

Symptoms of hypothermia:

As soon as you get into cold water the body begins to cool down. In the initial stages of the cooling process, you feel cold, pain and tingling in the skin, then a stinging in fingers and toes which moves to other parts of the body such as thighs, abdomen and back. At this stage you’re not close to hypothermia. In unhabituated winter swimmers, the initial cold pain will last from twenty seconds to a minute, at which point the cold numbs the skin and hyperventilation decreases. To protect against the high heat loss to the water, the body increases the metabolism by activating brown fat and skeletal muscles. You will feel this as slight shivering. When the shivering starts it’s time to get out of the water before the next stage of the cooling process occurs, when everything begins to move slower. It feels as though your skin is tightening, your muscles become stiff and you can’t move. At this stage the head feels cold at first, then a tingling and stinging sets in, before a kind of paralysis combined with “brain freeze”. Your breathing is also affected and slows, and speech becomes difficult. The condition is evident both visibly and audibly either in yourself or in others. The body is struggling to maintain its temperature at this point and you’re not well. You could go into convulsions.


Avoid winter swimming if you suffer from:

  • untreated coronary artery disease and/or chest pain (angina pectoris)
  • untreated high blood pressure
  • severe heart rhythm disturbances


Health benefits of cold water exposure:

Studies have suggested that cold-water swimming has a wide variety of health benefits, not only for general well-being, but also for the amelioration of mood disorders, changes in insulin sensitivity, hematological and endocrine function, and a reduction in upper respiratory tract infections. Surveys have found that winter swimmers suffering from arthritis, fibromyalgia or asthma had less pain after swimming, and experienced a general improvement in their sense of well-being. The physiological explanation is very likely the antiinflammatory effects of cold-water habituation.


Depression, dopamine, cold water and positive energy:

Speaking from my own experience, one thing that I absolutely love about ice baths and cold water exposure is that amazing feeling of “reset” after I get out of water. Whatever happened that day is gone. That feeling is hard to describe and I challenge you to try for yourself ! The positive energy is most likely due to an increase of the neurotransmitters dopamine and serotonin. These control mood and mental balance. Getting an increase in dopamine, challenging your body and mind and getting health benefits at the same time ? Yes, cold water exposure gives us all. In regards to depression, there are many stories online and in the book also of people who were on medication suffering from severe depression and how cold water exposure helped them to get over it.


The most important advice of them all: NEVER swim in the cold water alone, nor do cold plunge in your ice tub without supervision. Even when I’m doing cold plunge while sitting in my tub on our balcony I ALWAYS have my girlfriend watching over me. 



Take care, talk to you soon.



Disclaimer: Author talks about his experience only, when thinking about doing ice baths and showering with cold water you’ll need to see and try for yourself how your body responds and if in any doubt about your current health status always consult with a licensed physician. This web site is provided for educational and informational purposes only and does not constitute providing medical advice or professional services. The information provided should not be used for diagnosing or treating a health problem or disease, and those seeking personal medical advice should consult with a licensed physician.




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