by April McCarthy
A randomized intervention study from Japan has compared the physical
and mental health effects of daily full-immersion bathing with
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
However, in their latest
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
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'.
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
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.
intervention, scores for fatigue, stress and pain were significantly
lower, and 'smile' scored significantly higher, when compared to
General health, and skin
condition also improved after bathing, but not to a statistically
The team also investigated the difference in mood states after 2
weeks of showering or bathing. They used Profile of Mood States
scores to determine this.
POMS is used worldwide,
Following the bathing
intervention, POMS scores for tension-anxiety, depression-dejection,
and anger-hostility were significantly lower compared to the
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
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
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
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.
study of winter swimmers hints that cold water therapy can
stimulate increases in glutathione levels.
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
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.
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
noradrenalin - a chemical that
could help mitigate depression.
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.
high-explosive athletes are known to use ice baths to reduce
recuperation time and allow high-intensity training at increased
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
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
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.