Good News! Shivering Is a Form of Exercise

Enjoying the brutal winter weather? It may count as your daily workout. According to the results of a study published in the journal Cell Metabolism, being cold accelerates the metabolization of fat.
This is because of the way that brown fat reacts to cold temperatures. Brown fat is adipose tissue that can burn and create heat. When a person exercises, s/he produces the hormone irisin, which converts white fat to brown fat.
Until a few years ago, scientists thought that humans have brown fat only in infancy. As they age, they lose their brown fat and shiver as a substitute means of staying warm. Now we know that adults retain brown fat.
The researchers for this study had test subjects either exercise vigorously, exercise leisurely or lie on a bed in a cold room. They found that the people who exercised vigorously and those that lay shivering in bed produced high levels of irisin. Thus they both metabolized brown fat.