by April McCarthy

July 26, 2018

from PreventDisease Website






A randomized intervention study from Japan has compared the physical and mental health effects of daily full-immersion bathing with showering.


The participant-reported results add practical insight to theories in which is more favorable. There are many lifestyle choices that have a direct impact on our health, such as smoking, exercise and diet.


Could your bathing routine also be added to that list?


We know sporadic research that has been done suggests that regular exposure to cold water (via showers, baths or swims) may have some incredible health benefits.


Immersion of the body in water (immersion bathing), rather than showering, causes greater dilation of blood vessels.


Subsequently, there is improved replenishment of oxygen and nutrients to peripheral areas, together with better removal of carbon dioxide and other waste products, which refreshes the body.

In Japan, full-immersion bathing is a more common habit than in other countries, where showering prevails. A research group in Japan (Goto et al.) investigates the effects of immersion bathing against that of showering.


The team's previous studies recruited a cross-section of the Japanese population that immersion bathed daily - and the participants reported improved happiness, sleep and general health status, and reduced stress levels too.


However, in their latest study (Physical and Mental Effects of Bathing - A Randomized Intervention Study), Yasuaki Goto et al. conducted a clinical trial that compared the effects of immersion bathing versus showering over a period of time.




The team conducted a randomized controlled trial involving 38 participants that were equally split into two groups.


One group exclusively had 10-minute immersion baths once daily for two weeks, followed by two weeks of exclusive showering, and vice-versa for the other group.


Participants would then report daily on several aspects of their mental and physical health before and after either the bathing or showering routine.




Firstly, the participants self-reported on the following aspects before and after taking either a shower or bath:

general health, skin condition, fatigue, stress, pain and 'smile in the mirror'.

Unsurprisingly, the averaged results demonstrated statistically significant improvements reported for all aspects after having either a shower or a bath.


The amount of improvement for bathing was greater than for showering for all reported items, however the investigators did not determine if the differences were statistically significant.


Instead, Goto et al. asked the participants to retrospectively self-report on all the items after each two-week period of either bathing or showering.


After bathing intervention, scores for fatigue, stress and pain were significantly lower, and 'smile' scored significantly higher, when compared to showering.


General health, and skin condition also improved after bathing, but not to a statistically significant level.

The team also investigated the difference in mood states after 2 weeks of showering or bathing. They used Profile of Mood States (POMS) scores to determine this.


POMS is used worldwide, and measures,

  • tension-anxiety

  • depression-dejection

  • anger-hostility

  • fatigue

  • confusion

  • vigor

Following the bathing intervention, POMS scores for tension-anxiety, depression-dejection, and anger-hostility were significantly lower compared to the showering intervention.




This study advances the theoretical knowledge of the benefits of bathing over showering by reporting self-assessment findings from an interventional clinical trial.


The decreased fatigue and improved general health scores observed from bathing intervention could be due to improved metabolic action from bathing.


Also, the relaxing effect of bathing on muscles and joints may contribute to the decreased pain scores reported in this study. Therefore, the results from this investigation are beneficial.


However, it is always important to address this study's limitations:

  • The sample size is small - only 38 participants (with 5 withdrawals)

  • The trial was conducted in autumn, and so did not take seasonal differences into account

  • The timing of either the bathing or showering routine could not be strictly regulated

  • Generally, the Japanese population like immersion bathing more than other nations, and so these findings could be different if the study was conducted in Europe for example

Nevertheless, this trial has laid a positive foundation for future studies.


Also, the longitudinal structure to this trial is a positive - all participants experienced both bathing and showering, making it more likely that reported differences are due to immersion bathing causing them.








Why a Cold Shower More Beneficial for your Health than a Warm One
April 10, 2012
from PreventDisease Website






Most people cringe at the thought of a cold shower.


Just a glance at the many polar bear clubs dipping themselves into freezing water can make even those resistant to cold turn their heads away.


However, the sporadic research that has been done suggests that regular exposure to cold water (via showers, baths or swims) may have some incredible health benefits.

Most people are unaware that cool ambient and water temperature can have a positive impact on your health, primarily by boosting antioxidant levels and promoting better sleep.

Increasing Glutathione Production

Cold showers may increase glutathione - one of the body's most powerful endogenous antioxidants.


In fact, many of the antioxidants we ingest orally work by helping the body produce glutathione. While the body can make its own glutathione from other nutrients, if we try to take a glutathione pill, our bodies just can't seem to utilize it.


Encouragingly, a study of winter swimmers hints that cold water therapy can stimulate increases in glutathione levels.


Boosting the Immune System

A study from England found that taking daily cold showers increased the numbers of disease-fighting white blood cells (compared to people who took hot showers).


The investigators at Britain's Thrombosis Research Institute suggested that as the body tries to warm itself during and after a cold shower, metabolic rate speeds up and activates the immune system, which leads to the release of more white blood cells.


And, according to a German study, an occasional winter swim in cold water causes oxidative stress, but, done regularly, such swimming leads to an adaptive antioxidant response.


In other words, the body is better able to combat oxidative stress in general once it's accustomed to cold-water swims.


Relieves Depression

Lots of great men from history suffered bouts of depression. Henry David Thoreau is one such man.


But perhaps Thoreau's baths in chilly Walden Pond helped keep his black dog at bay.


Research at the Department of Radiation Oncology at Virginia Commonwealth University School of Medicine indicates that short cold showers may stimulate the brain's "blue spot" - the brain's primary source of noradrenalin - a chemical that could help mitigate depression.


Preventing Injury

Soaking in a cold bath (also known as an "ice bath" or "cold therapy") is said to help reduce swelling and tissue breakdown in runners after distance runs.


Endurance and high-explosive athletes are known to use ice baths to reduce recuperation time and allow high-intensity training at increased intervals.


Increases Testosterone

During the 19th century, many doctors and ministers recommended that young men take baths in cold water to reduce the sin of "self-pollution," i.e. masturbation.


Cold water was thought to extinguish a man's flaming carnal desires. However, the opposite was true.


A study by the Thrombosis Research Institute showed that cold water showers actually increase testosterone production in men. Increased testosterone levels not only boost a man's libido, but also his overall strength and energy level.


If you're looking to increase your testosterone, instead of using anabolics or testosterone medication, hop into a cold shower.


Enhancing Male Fertility

Higher scrotal temperatures depress sperm production, so much so that long-standing belief holds that hot baths might be an effective method of male contraception.


According to a study published in 1992, the "wet heat" method of contraception has been known since the 4th century B.C. and involves placing the testes in hot water (116º Fahrenheit - 47º Centigrade) for 45 minutes every night for three weeks.


This is supposed to provide protection for six months, but it isn't a very practical method.


More recently, the University of California at San Francisco did a study with men who were exposed to 30 minutes of hot baths for a week. When the men cut this exposure out, their sperm count went up by 491%, and their sperm's motility improved as well.


While switching from a hot to cold shower may not have as dramatic an effect, if you're trying to create some progeny, it surely won't hurt.