After the stage of believing that warm clothes and neoprene belts help us lose extra centimetres (and kilograms) gathered in fatty tissue, here comes the time for “slimming with cold”. There are ideas to use ice-cold shower in order to support the efficiency of nutrition and training procedures aimed at decreasing the level of fat in the body. But does it make any sense?
What is the brown fatty tissue?
The expression “fatty tissue” brings to mind a set of cells, of which the biological role is to gather spare energy in a form of triglycerides. However, it turns out, that such belief is not complete. First of all, fatty tissue is not homogeneous when it comes to its structure and functions, besides, it may gather energy and use it in the processes of synthesis of biologically active compounds, as well as in the processes of producing heat! It's the white fatty tissue, which is placed under the skin (and creates the characteristic folds within the central part of the body), as well as outside the abdominal cavity (it's so-called visceral fat), that plays the role of a “deposit” in human body. This kind of tissue is mainly the reserve of energy, and it also shows the endocrine activity by excreting biologically active substances called adipokines.
Apart from white fatty tissue, we also have brown fatty tissue - “BAT” (brown adipose tissue). Its properties are totally different.
The structure and functions of BAT
Brown adipose tissue, opposite to the white one, is very vascularized, and the cells that create it have high concentration of mitochondria, i.e. microsomes, of which the role may be compared to a small power plant, where energy is released from substrates, such as fatty acids. Brown fatty tissue is responsible for the process of thermogenesis, i.e. the cycles of biochemical reactions aimed at producing heat. So, on the one hand, BAT takes part in sustaining the proper warmth of the body, on the other – it influences the processes, which regulate energetic balance. Therefore, it's good to highlight that the body mass and composition depend on the activity of BAT. What's interesting, it was thought for a long time that BAT occurs only in small children and disappears totally with age. However, scientific studies have shown that this kind of tissue is also present in adults, but its amount may vary among particular individuals. And this is the main point of this article.
Brown adipose cells can occur or disappear because of few factors. Genetics plays some part in this process, but the influence of environmental factors is also very important: lifestyle, as well as its consequences – body mass and composition.
For example, it was observed, that the level of brown fatty tissue is significantly lower in people with excessive body weight and in diabetics. Lack of physical activity also contributes to decreasing the amount of BAT... The available scientific data point out that, on the one hand, the increase of body mass fosters decreasing the amount of BAT in the body, but on the other hand, low level of BAT fosters the development of overweight and obesity. Therefore, there is the situation of vicious circle, and an interesting observation appears.
The studies done on animal material show that the adaptation of the body to low temperature (as a consequence of the climate or season change) happens along with significant increase of the amount of BAT, which is created out of white fatty tissue! This process is called transdifferentiation! This dependency is confirmed in the studies on cell farms. Therefore, it's possible to risk the hypothesis, that we are able to increase the amount and activity of BAT by being exposed to low temperature, which is why we can increase the process of burning spare fat!
Cold shower in practice – doubts
I suppose, that cold shower is the simplest way to ensure the exposure to low temperature in controlled (predictable) conditions. But are we able to increase the synthesis of BAT and its activity this way? Well, there are reasons to believe that, although, this dependency has not been verified in scientific research yet. The problem may be in setting the length of such shower. After all, it does not reflect the circumstances occurring in nature, which are the factors causing the increase of the amount of BAT. So, is there any reference time period after which the amount of brown fatty cells increases more efficiently? It's impossible to find the answer for such question... Another mystery is the temperature the water would have to have to make such bath “efficient”. Unfortunately, there is no source information yet. Additionally, not every body reacts well on the influence of such procedures, especially if they are extreme – in some people with lower immunity, there may occur some infections. And there is also the most depressing thought connected with the influence of cold shower on the feeling of hunger. It's good to know that the exposure to low temperature causes the increase of appetite, which is connected with stimulating the thermoreceptors. The result is really strong – it's possible to observe it in summer (nobody feels like eating during summer, and we eat more in winter, and we also choose more solid food then).
Taking cold shower seems to be an option, which may have potential use in supporting the reduction of fatty tissue both occassionally (cold causes stronger energy expenditure), and probably in long term (by stimulating the process of transdifferentiation of the white fatty tissue cells into brown ones). It may also influence the release of growth hormone – although this aspect is the most doubtful of all. Before starting such procedures, however, you shoud take under consideration the fact that their efficiency has not been verified yet, and that their result may be: the upper respiratory tract infections and visibly increased appetite.