Tag Archives: weight loss

Weight Loss

Some basic reasoning tells us that cold showers can assist in weight loss. Consider the acute effects of a cold shower. The water hits the skin and almost immediately the body jump starts; blood flow increases, muscles harden, and heart rate increases. All of these things require energy.

It may help to think of the body as a heat engine. A typical heat engine utilizes a hot reservoir and a cold reservoir to run a motor, as in the diagram below. Only, instead of a motor, the body runs various metabolic processes.

Why Your Body is Warmer Than the Environment

Why Your Body is Warmer Than the Environment





Like a heat engine, the body must transfer heat to the environment. Even on a blistering hot day, we transfer latent heat to the air by sweating. Internal body temperature is the “hot reservoir” of the heat engine, while the “cold reservoir” is the air (or water) that surrounds the body. Without this transfer of heat, the energy of all our metabolic processes would have nowhere to go.

The key is that the metabolic output (W), equals the amount of heat flowing from the hot to cold reservoir. Taking a cold shower or bath forces you to burn more energy. And by estimating water temperature, you could calculate approximately how much.

In a 2.5 year experiment, rats of equal age were gradually accustomed to standing in cool water (at 23° C, 73° F) until they were standing in it 4 hours per day, 5 days per week. Even though the rats ingested 44% more food than the control group, their body weight was significantly lower. Incidentally, their lifespan was also slightly longer (by approximately 5%), and they had significantly fewer tumor formations [1].

This also trains your physiology to deal with colder temperatures, raising your resting metabolism. This is similar to the effect of physical exercise. The only difference is that while working out raises it through a direct stimulus to metabolism (through will power), showering in cold water is more of an indirect stimulus.

[1] http://www.ncbi.nlm.nih.gov/pubmed/3781978

Activate Brown Fat

 

baby

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.