Lately it seems like cold showers (and cold bathing) have been getting a lot of attention. Their proponents would have us believe that they can help us with everything from mental health to weight loss. As someone who really treasures the comfort of a hot shower, I wanted to see if cold showers live up to all the hype. As I found out, there is not much scientific research to back up many of these claims. The good news is that the verified benefits of cold showers can be attained with just a short blast of cold water—or by using lukewarm water. Let’s go through these alleged benefits one by one.
Preventing Dry Skin
The main scientifically-backed benefit of taking colder showers seems to be in helping to prevent dry skin. To understand why, it helps to know that your skin’s outermost layer, the Stratum Corneum, is composed of layers of flattened keratin cells embedded in a lipid matrix. This lipid matrix is made up largely of oils produced by your skin. The Stratum Corneum functions as the primary barrier that keeps moisture from leaving your body and skin—like a piece of cling wrap.
Heat can disrupt the Stratum Corneum, and for that matter, so can water. Hot water seems to make the lipid matrix in your Stratum Corneum more viscous—and thus more susceptible to disruption and damage. When your Stratum Corneum is disrupted it can lead to your skin losing moisture. This is a particular problem if you are prone to eczema or have sensitive skin.
Fortunately, you don’t need super cold water to help your Stratum Corneum remain more intact—simply showering or bathing with lukewarm water will help prevent this kind of damage from happening. Shorter showers are also key—the less time hot water is hitting your skin, the less it will disturb your lipid layer. And you’ll be saving water!
The evidence that regularly subjecting yourself to a blast of cold water will boost your immunity is fairly compelling. In 2015, Dutch scientists conducted an experiment involving over 3,000 people, requiring them to regularly shower in cold water for between 30 and 90 seconds. The results showed that those who took the cold showers had fewer sick days at work. The mechanism for this effect is not really understood, and the study’s authors admit that a “placebo-like” effect cannot be ruled out.
The good news if you’re hoping to boost your immunity in this way, is that a 30-second blast of cold water is all that’s needed to get the positive effects. In fact, the Dutch study allowed participants to take hot showers, as long as that shower ended with a cold blast. Exhilarating!
The scientific evidence for this is indirect at best. The reasoning seems to be that cold water induces a set of physiological effects in your body—such as increased heart rate and elevated respiratory rate—which then bring about alertness. As this hasn’t been rigorously studied, we don’t really know how long the alertness lasts, or whether it helps you do better on a math exam or stay awake on the road. That said, this benefit seems like common sense: a cold water plunge will certainly wake you up!
There is a theory that cold water therapy (hydrotherapy) helps with depression and anxiety—though the research is threadbare. One hypothesis is that cold water improves circulation and lowers your blood pressure—which in turn reduces anxiety. Another hypothesis is that cold water increases the release of endorphins in your brain, thus easing symptoms of depression and anxiety.
But these are just hypotheses. An oft-cited 2007 “study” about this is just a statement of this hypothesis, with the proposal that it merits further testing. Unfortunately, the study is frequently cited as evidence when it actually provides none. There is another 2018 study that has gotten attention about cold-water swimming as a therapy for Major Depressive Disorder. How many people with depression participated in this study, you ask? One. But yes, for that one person, the therapy seemed to be effective.
This one defies scientific sense, and for that matter, common sense. The idea seems to be that the same physiological effects described above also increase your body’s metabolic rate—the speed at which your body burns calories. Though this may be true, your metabolic rate is only really elevated for the duration of the shower—so you would have to take a really long shower for this to have a noticeable effect. In any case, I couldn’t find any studies that tested this claim. If you’re interested in weight loss, I suggest you skip this and stick with more traditional methods.
The main benefit of colder water for showers seems to be preventing dry skin, though this does not require you to shower in ice-cold water. Turning the temperature down to a lukewarm setting will provide you with great benefit. Another potential benefit of cold showers is boosting immunity, which you can achieve with a 30-second cold blast at the end of your shower. It’ll probably wake you up too—especially if you combine it with our Peppermint Pure-Castile Soap!