Author’s Note: In this article, I will use multiple published research articles to support the points I make. This article is not meant as a critique of any of these papers, rather they are used to support or help prove the points being made. Also, my intention with these articles is to present the information within them as close to the author’s intent to the best of my ability. If you believe I misrepresent any of the information in the referenced sources, please feel free to let me know.
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There is a lot of talk about cold shower and their supposed incredible benefits. There are those like Wim Hoff who tout the life changing effects of cold showers and countless articles online speaking of why you should be taking a cold shower. In the following article, I read a host of published research papers to figure out exactly what cold showers can do for you. I used only published research paper and I try to provide quantitative evidence when possible to support the ideas brought forth.
Although, I do not believe that cold showers are the greatest things since barred soap, the research, as I will show, does point to some positive effects of incorporating cold showers into one’s routine. In this article, I will help you understand the effects of cold showers and when to take cold showers. But before we get to all that, we need to cover a few things, mainly, what is considered a cold shower and how do you get your body ready to take one. Considering most people would run out of the shower if it were even slightly colder than usual, these are important questions. With all that out of the way, here is the first order of business:
What Constitutes a Cold Shower?
There is no singular answer to this question, since much of the research studying ‘cold’ showers uses vastly different temperatures of water. I’ve seen anything from 2°C (~36°F) to 10°C (~50°F) all the way to 22°C (~72°F). It is worth noting that the average shower water temperature is 40°C or 105°F. This means that any of these cold temperatures are considerably lower than what you may be used to. (I checked my own regular showering temperature which I found to be about 90°F and the coldest my shower reached was about 72°F).
How Do I measure My Water Temperature?
Use a thermometer. If you do not want to waste any water, put a bucket or bowl in the shower and allow it to fill. Once it is full enough, use a thermometer to measure. Either stick one in the bucket or use an infrared thermometer to measure temperature. I bought this one from Amazon for $16. I have not had any trouble with it.
How Do I Become Habituated to Cold Showers?
This is usually the hardest part for most people. Even if you take one cold shower, it is hard to do it consistently. The solution is as with most things in life, take it one step at a time. In one study, scientists tested the ability of the body to habituate to cold showers through continued cold showers. Subjects took two cold showers a day (some at 10°C and others at 15°C) for 3 days. All the groups taking cold showers showed a smaller change in hart rate and respiratory frequency when comparing the first and last showers taken. The same subjects were immersed in cold water at the start and end of the experiment. Those taking 10°C showers had smaller changes to biometric readings compared to those taking 15°C cold showers. Other previous studies showed that those taking baths in cold water habituated better than those taking cold showers.
The combination of studies shows that there are two major factors affecting habituation to cold showers, the length of the shower and surface area exposed to cold water. Taking these facts into account, it is best to start a habituating the body through small showers, which target a specific area of the body (ideally the upper torso). The most commonly recommended strategy is to start with a 30 second shower at the end of your regular showers, then to increase it over time. The next question must then be: How long should the shower be? Unfortunately, this question does not have one-size-fits-all answer. Depending on the purpose of the specific cold shower, both the temperature and length of the shower may differ for optimal results.
What Are the Benefits of Cold Showers?
There are many claimed benefits of cold showers. Although, through y research, I have found only a few of these claims backed by published research. Most of the remaining claimed benefits of cold showers are either implied through the benefits known of similar treatments or conditions or even just through analogies. The problem with the latter two types of claims is that there is no known analytical data showing the extent of these benefits. Without data to support them, these claims may prove to be minimal, or even non-existent. I will still list all the claimed benefits of cold showers, but I will also point out their lack of supporting research.
1. Relax the body after Workout
This is one of the most researched effects of cold showers and the one with the most evidence behind it. Multiple research papers have been published around this subject with varying experimental setups. The research has shown that, although cold-water immersion (CWI) is the most effective way to return a heated body to homeostasis, cold showers have a similarly beneficial effect. Studies have been conducted with those who have performed heavy workouts, those suffering from hyperthermia, and those using saunas.
Cold showers have been proven to help lower heart rate, blood pressure, and respiratory frequency.
Research has shown the benefits of both cold-water immersion (immersing the whole body into cold water) and cold showers are beneficial after intense workouts. Although the benefits of CWI are greater than a cold shower, both have shown to return the body to homeostasis quicker than not using anything at all. The effectiveness of cold showers is dependent on both the temperature and the surface area of the body with which it comes in contact. Cold showers help reduce blood pressure, heart rate and respiratory frequency. As one research paper mentions, “The cold-induced cutaneous vasoconstriction that occurs with CS probably enhanced venous return and increased central venous pressure, causing a reduction in HR”.
2. Decrease Depression symptoms
Research shows that cold showers can, in fact, help tackle depression. The shock of the cold activates the sympathetic nervous (fight or flight response). The activation of the sympathetic nervous system increases plasma noradrenaline (or norepinephrine as it is also called) concentrations. Decreases in norepinephrine concentrations in the brain have been linked to depression. One study showed that cold-water immersion at 14°C/57°F for 1 hour increase norepinephrine concentrations in the plasma by 530%. Another study showed that high release of norepinephrine could be accomplished much quicker, with just 20 seconds of CWI when the water was even colder at 0-2°C/32-35°F. Another study tracked the real life applications of cold-water shows by tracking large groups of people. One group was instructed to take cold showers daily over a long period of time, while the other continued its regular routine. The study found that people who took cold showers had almost 30% less sick days at work than their control-group counterparts and expressed higher overall levels of happiness in their day-to-day lives.
Unfortunately though, there is some bad news. The research relating cold exposure to increased norepinephrine release only studied cold-water immersion, not cold showers. It also showed that the water needed to be around 14°C or 57°F to be effective (the study also used 20°C/68°F, with no increase in released norepinephrine). As explained earlier, other studies have shown that CWI has a greater effect on the body than regular cold showers do. The authors of the study tracking people’s reported happiness levels also indicated shortcomings in their own research related to this topic.
3. Increased Metabolic Rate Leading to Increased Health
Studies have shown that exposure to noninfectious stimuli could activate the human immune system. One study specifically studied exposure to the cold and its effects on the human immune system. It showed that the concentration of different T-cells increased in the blood stream caused by increased metabolic activity due to shivering. It is worth noting though, that the researchers also note that the extent to the activation of the immune system and the significance of this activation are not fully understood.
4. Habituation to the Cold and More
This effect may seem obvious, but it is worth noting, especially for those living in colder environments. Exposure to cold water, both through cold-water immersion and cold showers, increases habituation to cold exposure. Much of this was mentioned earlier, so to keep it brief, taking cold showers will increase a person’s ability to withstand the cold. This is, of course, effective when starting to incorporate cold showers in to your regular routine, but it has the added effect of help you handle different kinds of cold with less adversity. The greatest exemplar of this is Wim Hoff and his famous Wim Hoff. He explains his methods and philosophy in his book The Wim Hof Method, as well as his many seminars. The idea is that exposure to cold, along with other factors like meditation, can lead to more resilience and control in everyday life.
Conclusion
Cold showers can have a host of positive effects on the short-term recovery and long-term health of a person. There are clear techniques to habituate the body to taking cold showers and it is relatively easy to incorporate them into everyday life. It is also not necessary to take a cold shower every single day to see the positive effects. Much of the research studying the long-term effects of cold showers had subjects only take showers 3 times a week. Unless you are immunocompromised, the potential downsides are minimal.
Unfortunately, there is still not enough research showing the effects of cold showers. Two pieces of information make me believe this to be true, the first: temperature and total body exposure determine the effectiveness of cold exposure, the second: most of the published research studies cold-water immersion, rather than regular cold showers. Although it is likely that the effects of cold showers is similar to that of CWI, but to a lesser degree, as was proven to be the case with habituation, without actual research, we can never be sure.
Works Cited:
- Stabilizing Bioimpedance-Vector-Analysis Measures With a 10-Minute Cold Shower After Running Exercise to Enable Assessment of Body Hydration (doi: 10.1123/ijspp.2018-0676.)
- The Effect of 16-Minute Thermal Stress and 2-Minute Cold Water Immersion on the Physiological Parameters of Young Sedentary Men (DOI: 10.26773/mjssm.200308)
- Effects of cold mist shower on patients with inflammatory arthritis: a crossover controlled clinical trial (DOI: 10.1080/03009742.2016.1199733)
- Physiologic and Perceptual Responses to Cold- Shower Cooling After Exercise-Induced Hyperthermia (DOI: 10.4085/1062-6050-51.4.01)
- The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial (doi: 10.1371/journal.pone.0161749)
- Repeated cold showers as a method of habituating humans to the initial responses to cold water immersion (DOI: 10.1007/s00421-004-1239-6)