Strengthen Immune System

immunesystemCold showers are sometimes touted as a preventative tonic for colds, flu, and infections. However, are these reported benefits just a placebo effect – the power of suggestion, or do cold showers have a direct and measurable effect on our immunity?

Once again, studies show at least some support for the popular wisdom. An experiment in Prague studied the effect of cold water immersions on athletic young men. They immersed them in water at 14 °C (57 °F), three times a week for six weeks. They concluded that the immersions activated the immune system “to a slight extent”.

Among many changes, they saw increased levels of two types of white blood cells: monocytes and lymphocytes. While certain lymphocytes are instrumental in eliminating bacteria, viruses, and toxins, monocytes are indirectly responsible for the engulfing and consuming of pathogens and foreign materials [2,3].

Considering these effects, it’s no surprise that mice exposed to 8 days of brief cold water stress survived significantly longer when exposed to the intracellular parasite, Toxoplasma gondii [4].

So, cold showers can help keep away the sniffles, but who knows what other nasty virus or pathogen you might also happen to ward off?

[1] Immune system of cold-exposed and cold-adapted humans.
[4] Cold stress-induced modulation of cell immunity during acute Toxoplasma Gondii infection in mice.

Precautions and Guidelines

As for all therapies, the precondition is “first, do no harm”. Following these guidelines will help you receive maximal benefit from cold water therapy and avoid adverse effects.

1) Listen to your body.

When you exercise, you probably notice a point where you feel satisfied with your workout. Up to a point, exercising leaves us feeling energized throughout the day. But if overdone, it can cause persistent feelings of exhaustion and lethargy. Cold showers are the same way; a quick, cold shower should leave you feeling invigorated. But, too long and cold of a shower can leave one feeling chilled and sluggish. Always calibrate your application to invigorate, but not freeze yourself.

2) Do not use “ice cold” water.

You do not want to overstress your system with excessively cold water. Sebastion Kneipp, one of the founders of naturopathic medicine, utilized water anywhere from 50 °F to 68 °F. However, note that a shower can feel colder than its actual temperature.

3) Adjust duration to personal response.

In general, take shorter applications of colder water, and longer applications of warmer water. Again, use your body’s response as your gauge. You may need to work your way up to longer applications if just starting out. You can also adjust the duration to compensate for seasonal fluctuations in water temperature.

4) Curb the intensity if you are elderly or sick.

If you are not healthy, try progressively splashing water onto the body, or just applying cold water to one body part. Those susceptible to heart attacks should know that cold water can exacerbate stress on the heart, much like heavy exercise, and could potentially trigger heart attack or stroke. Only a doctor can say whether cold showers are compatible with your particular physiology.

Activate Brown Fat



Babies typically have a constitution of 5% brown fat. It is one of their main mechanisms for staying warm.

Many people report that they feel warmer throughout the day after taking a cold shower or bath. This could partly be due to enhanced circulation, but the stimulation of brown fat also seems a likely cofactor.

Brown fat is one of two types of fat in the body – the other being white fat, or what we normally just refer to as “body fat”. While white fat should be kept to a minimum, brown fat is beneficial because it helps burn calories and generate body heat. A study at the University of Maastricht in the Netherlands revealed that obese people have less brown fat than lean people [1].

A cold shower could be a good way to stimulate the body’s supply of brown fat. A branch of the aforementioned university found that in men, exposure to chilly temperatures increased the metabolic rate of brown fat 15-fold. Sustaining this rate alone could help a person shed 9 pounds a year. Women typically have twice as much brown fat as men [1].

In a Chinese experiment involving voles exposed to a 5° C environment, they found that the “thermogenic capacity” of brown fat increased; the cold-exposed voles had a higher content of uncoupling protein 1 in their brown fat, increasing their ability to convert stored calories into heat [2].

However, in one small study of six men, the researchers did not find that their adaption to cold was facilitated by brown fat [3]. Hopefully future studies will find the most favorable conditions for activating brown fat and the precise benefits we can expect.

[1] Brown Fat: Don’t Try To Burn It
[2] Cold exposure does not decrease serum leptin concentration, but increases energy intake and thermogenic capacity in pregnant Brandt’s voles (Lasiopodomys brandtii).
[3] Effects of acclimitazation to cold baths on men’s responses to whole-body cooling in air.

Hot Showers Release Toxic Chemicals

What's In Your Water?

What's In Your Water?

Cold showers not only offer their own benefits, but help shield you from the deleterious effects of hot showers. It may sound like a paranoid concern, but experts unanimously agree: hot showers vaporize dangerous amounts of chlorine and other toxical chemicals into the air. This has been acknowledged by the presigious magazine, New Scientist, professor of Water Chemistry, J. Andelman, and the National Academy of Sciences.

“I tell my friends to take quick, cold showers”, said Jullian B. Andelman, Professor of Water Chemistry, University of Pittsburgh, who claimed that the longer and hotter the shower, the more chemicals build up in the air.” – San Jose Mercury News, September 11 1986

“Taking showers is a health risk, according to research presented last week in a meeting of the American Chemical Society. Showers – and to a lesser extent baths – lead to a greater exposure to toxic chemicals contained in water supplies than does drinking water. The chemicals evaporate out of the water and are inhaled. They can also spread through the house and be inhaled by others.” - New Scientist – 18 September 1986, Ian Anderson

“The National Academy of Sciences estimates that 200 to 1,000 people die in the United States each year from cancers caused by ingesting the contaminants in water. The major health threat posed by these pollutants is far more likely to be from their inhalation as air pollutants. The reason that emissions are high is because water droplets dispersed by the shower head have a larger surface-to-value ration than water streaming into the bath.” - Science News – Vol. 130, Janet Raloff

To summarize the above quotes, both the heat and the dispersion of water in a hot shower make carcinogens more likely to vaporize into the air than from a cold shower or bath. Note that while only 200 to 1,000 cancers (in the U.S.) are estimated to be caused directly by these chemicals, cancers usually arise from a combination of multiple offending elements and a weakened immune system. Even if you do not land in this small pool of unlucky victims, hot showers are probably not a healthy habit for overall health.

Also be wary of hot tubs or whirpool baths. Municipal tap water is required to have at least 0.2 ppm of chlorine (enough to kill some fish). Pools typically have between 2.0 and 4.0 ppm chlorine [1]. Hot tubs may be especially dangerous because they could mimic the “hot shower effect” with high chlorine concentrations, generating steam via the water turbulence. This seems like more than ample reason to avoid habitually soaking in hot tubs.

A better alternative to hot showers is combining infrared saunas with cold showers.

[1] American Chemistry, Chlorine Tips