Why should we enjoy the cold?
It turns out that shivering with cold is very useful. A recent study shows that shaking, along with exercise, can stimulate the conversion of white adipose tissue to brown, which in turn promotes weight loss.
Dr. Paul Lee, an endocrinologist at the Harvan Institute in Sydney, Australia, has found a link between fat and muscle tissues that interact thanks to specific hormones stimulating white adipose tissue cells into brown ones. thus providing protection from the cold.
The results of his research were published in the journal Cell Metabolism. White adipose tissue accumulates energy – about 50 grams of it can accumulate over 300 kilocalories.
Such amount of brown adipose tissue, on the contrary, can burn about 300 kilocalories per day.
Dr. Lee showed that during exposure to the cold, as well as exercise, the level of the hormone irisin, which is released from muscles, and the concentration of FGF21, which is produced by brown adipose tissue , rose.
In laboratory conditions, irisin and FGF21 were able to convert white adipose cells to brown in 6 days.
We are all born with a small amount of brown adipose tissue in the area around the neck – it helps maintain body temperature and conserve heat.
Until recently, it was believed that brown adipose tissue disappears in early childhood, that it is present in adults as well, and more so in those who are slim.
“The number of studies on brown adipose tissue is now growing rapidly because its ability to burn more calories will help fight obesity and diabetes,” explains Dr. Lee.
Blood sugar levels are on average lower in people who have more brown fat. In his study, Dr. Lee explains exactly how brown adipose tissue is activated.
When the human body senses changes in the environment and reacts to them thanks to the function of the nervous system and the action of hormones.
“When we are cold, the body activates the cells of the brown fat tissue as energy is burned and a lot of heat is generated as a result.”
When this energy is not enough, the muscles start to contract – shivering occurs and thus heat is generated. However, we do not know exactly how muscle and fat tissue interact in this situation” – he points out doctor Lee.
“We introduced the volunteers to the cold, lowering the ambient temperature from 18 to 12 degrees Celsius, until all participants started shivering. We took a blood sample from each participant to determine hormone levels and also determined muscle tremors using devices that attach to the skin and measure the electrical activity of the muscles. ”
The scientists found that the volunteers began to shiver at a temperature between 16 and 14 degrees Celsius.
” We found that two hormones responded to the cold – irisin and FGF21, secreted by muscle and brown adipose tissue respectively. These hormones increased the levels of energy consumption by fat cells, which immediately began to release heat, which is characteristic of the brown adipose tissue,” Dr. Lee also points out.
Dr. Lee also suggested that all participants in the experiment undergo another exercise test to compare the two processes.
“We found that from 1 hour of training at a moderate pace on an ergometer, the same amount of irisin is formed as when shivering from the cold for 10-15 minutes” – he also notes.
And maybe very soon, obesity and diabetes prevention will be carried out by means of the body’s own resources – the accumulations of brown adipose tissue.
