Our body(and mind) needs to experiment with stress and stimuli which lead it to adapt, improve, and ultimately getting stronger and healthier.

However, stress and stimuli are rarely comfortable while experienced, and unfortunately, a lot of people decide to spend their lives entirely away from situations that cause them distress.

This aversion towards discomfort has caused us to reduce the stimulation of the environment on our body. During the winter we wear heavy clothes to feel warm, or we artificially regulate the temperature of our homes or offices.

This leads us to get weaker in the mind but mostly in the body which sees its incredible ability to adapt(on which, our all evolution is based) turning numb and as a result, we become more likely to get sick.

It's a fact, people who make sure to undergo a moderate, regular flow of stress and stimuli are healthier than the ones who don't.

A practical and straightforward way to awake our adaptation ability and make us more robust and energetic is a nice cold shower.

Benefits of Cold Shower                                                                             

Fortifies the immune system

A cold shower can make us healthier by making our immune system stronger.

Studies say that cold stress repeated daily can have a stimulating effect on cell-mediated immunity(1)

Daily cold stress can increase both numbers and activity of the major effectors of adaptive and innate tumor immunity; it may also lead to an enhanced antitumor immunity and improve nonlymphoid cancer survival rate. (2)

Reduces inflammatory pain

A cold shower can reduce muscle soreness and pains by stimulating the brain causing a pain-relieving effect.

Also, a study (3) showed that in a case of chronic inflammatory arthritis patients treated with cold showers for one week experimented a reduction in pain and an improvement in sleep quality in the period of the treatment, with no relevant side effects.

Helps burning fat                                                                                                                                                                                 
^{In our body, we have brown adipose tissue or brown fat, and white adipose tissue or white fat.
The main difference between the two is that white fat is specialized in storing energy primarily in the form of triglycerides while brown fat burns energy by generating heat.}

Has been shown (4) that a ten days long cold acclimation protocol increases brown fat activity without differences between sexes, in parallel with an increase in nonshivering thermogenesis (which is an increase of heat generated caused by cold exposure without muscle shivering)

Cold exposure can be an effective way to increase energy consumption with consequently enhanced capacity of burning fat.

Helps to treat depression

^{Depression is a mood disorder that generates a constant feeling of sadness and uninterest towards the world around us which can hinder our engagement in daily activities and causes a variety of emotional and physical problems.}

A hypothesis is that depression might be caused by the lack of certain types of stress experienced by our ancestors during evolution, like the exposure to changes in body temperature, and the presence in some people of genetic makeup that make individuals more affected by the lack of these stressors.

Cold shower activates the sympathetic nervous system and increases the production of endorphins, the "feel-good" chemicals that improve happiness and relief pain; the treatment of depressive symptoms with cold showers resulted in being very effective. (5)

How to take a cold shower safely

The most important thing is to take our time and listen to our body without overreacting. If we feel heavy shivering or numbness, it could be that we may have stayed under the cold water for too long so, get warm a try another time for a shorter period.

However, if done correctly there isn't any relevant side effect to this practice.

How much time under the cold water
An excellent way to start is to end our usual warm shower with 10 seconds of cold water.

With time we'll increase the time we spend under cold water until it's possible to get a shower only with cold water.

This process will take time, and after a couple of weeks, we should be able to be comfortable to increase our time under the cold jet.

How to pour cold water on your body

^{Starting from the feet make the cold feeling less shocking. After the feet come up to legs then, arms, shoulders, stomach, head, neck and lastly the back.}

While the cold water flows on our body, we might get anxious and start to hyperventilate, if it happens to you stay calm and breathe. Feel the cold and appreciate it; the cold water in your shower will not kill you so remain calm and collected. After 10 seconds get out. The time under cold water will increase over time.

Integrating a cold shower in our daily routine doesn't take much. We have to get under the water and experiment. The benefits that we get from it are definitely worth the initial struggle.

References:
(1)Nikolai A Shevchuk, Sasa Radoja, Possible stimulation of anti-tumor immunity using repeated cold stress: a hypothesis.BioMed Central, 13 November 2007. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2211456/>

(2) Mooventhan A, Nivethitha L. Scientific evidence-based effects of hydrotherapy on various systems of the body. North Am J Med Sci 2014;6:199-209 <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049052/#ref81>

(3)H Hinkka, S Väättänen, S Ala-Peijari & T Nummi, Effects of cold mist shower on patients with inflammatory arthritis: a crossover controlled clinical trial, Scandinavian Journal of Rheumatology, 30 Aug 2016.<https://www.tandfonline.com/doi/abs/10.1080/03009742.2016.1199733>

(4) Anouk A.J.J. van der Lans, Joris Hoeks, Boudewijn Brans, Guy H.E.J. Vijgen, Mariëlle G.W. Visser, Maarten J. Vosselman, Jan Hansen, Johanna A. Jörgensen, Jun Wu, Felix M. Mottaghy, Patrick Schrauwen, and Wouter D. van Marken Lichtenbelt, Cold acclimation recruits human brown fat and increases nonshivering thermogenesis, The Journal of Clinical Investigation, 15 July 2013, <https://www.jci.org/articles/view/68993?trendmd-shared=1&utm_campaign=impact_2013_august&utm_content=short_url&utm_medium=pdf&utm_source=impact>

(5) Nikolai A.Shevchuk, Adapted cold shower as a potential treatment for depression, Medical Hypotheses Volume 70, Issue 5, 2008, Pages 995-1001, 13 November 2007, <https://www.sciencedirect.com/science/article/pii/S030698770700566X?via%3Dihub>