American Council on Exercise by American Council on Exercise

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We all know that exercising regularly boasts many benefits — improving energy, strength, balance, coordination, and even creating new brain cells. Now, researchers led by the Dana-Farber Cancer Institute and Harvard Medical School have discovered the exercise-induced natural hormone in muscle cells that triggers all these benefits, NYTimes reported. The hormone turns white fat into the more desirable brown fat and could lead to obesity and diabetes prevention.

The study, published on Wednesday in Nature, is a groundbreaking step in understanding the biological processes that happen as a result of exercise.

“There has been a feeling in the field that exercise ‘talks to’ various tissues in the body,” said Bruce Spiegelman, a cell biologist at Dana-Farber and co-author of the study. “But the question has been, how?”

Researchers discovered that exercise leads to a cascade of changes, including production of a hormone no one had previously identified. They dubbed it "irisin," after the Greek messenger goddess, Iris, because it sends important messages to our fat cells.

Though produced in our muscles, irisin travels to our fat cells and turns visceral, storehouse white fat into metabolically active, calorie-burning brown fat. We want more brown fat, so it seems exercise doesn't just lead to more muscles.

Irisin also makes us more sensitive to glucose, which is important for preventing diabetes. Fattened, inactive mice who were injected with irisin did not develop diabetes and even lost some weight — without sweating.

The fact that irisin injections mimicked the benefits of exercise leads to questions about whether this hormone can be used as therapy to help people who are unable to work out fight obesity and diabetes. 

Before you think this potential means you don't ever have to hit the gym or road, Spiegelman said irisin won't make your muscles stronger. So get moving and be glad that elevated irisin is sending beneficial messages throughout your body.

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