Shivering from cold is as effective as exercise in cutting down body fat as they both produce hormones that trigger the creation of calorie-burning 'brown fat,' according to a University of Sydney study.
It is a well-known fact that 'bad' white fat stores energy, while the good brown fat burns it up. The good 'brown fat' was previously believed to exist only in babies but recently discovered in adults as well. Slimmer adults possess the fat in larger quantities than others.
Researchers found that exposure to the cold temperatures led to the production of the two hormones called irisin and FGF21. Laboratory experiments showed that these hormones converted white fat cells into brown fat cells over a period of six days.
"We identified two hormones that are stimulated by cold - irisin and FGF21- released from shivering muscle and brown fat respectively," said study leader Dr Paul Lee, from the University of Sydney in Australia. "These hormones fired up the energy-burning rate of human brown fat cells in the laboratory, and the treated fat cells began to emit heat, a hallmark of brown fat function," Telegraph reports.
For the study, the researchers first exposed participants in temperatures of less than 59F (15C) for around 10-15 minutes and then asked them to pedal an exercise cycle for an hour. The researchers found that an hour of moderate exercise produced the same amount of irisin from the muscle tissue as trembling for 10-15 minutes.
"Excitement in the brown fat field has risen significantly over the last few years because its energy-burning nature makes it a potential therapeutic target against obesity and diabetes,' said Dr Lee. "White fat transformation into brown fat could protect animals against diabetes, obesity and fatty liver. Glucose levels are lower in humans with more brown fat."
Maastricht University researchers said that as people are habituated to spending majority of their time in warm indoor temperatures, they are at a greater risk of becoming obese and developing overweight related conditions including heart disease, stroke, high blood pressure, diabetes, cancer, gallbladder disease, gallstones, osteoarthritis and gout others.
"By lack of exposure to a varied ambient temperature, whole populations may be prone to develop diseases like obesity. In addition, people become vulnerable to sudden changes in ambient temperature," said Marken Lichtenbelt, the lead author of the paper, The Telegraph reported.
