- In 2003, biologists Mark Febbraio, from Australia, and Bente
Pedersen, of Denmark, figured out that muscle is an endocrine organ,
just like fat, and that exercising muscle produces chemical
secretions—which they called myokines—that communicate with the rest of
the body. As Pedersen puts it: “Skeletal muscle is the organ that
Febbraio and Pedersen identified the most common myokine as none other than IL-6, the inflammatory cytokine that’s also produced by excess fat. But when released during exercise, they found, IL-6 actually had beneficial effects, telling the liver to increase the rate of fat oxidation. “When we made this discovery, people really didn’t believe us, because IL-6 was considered a bad actor in many diseases,” says Febbraio, a former professional triathlete. “But the thing is, in exercise it’s actually anti-inflammatory.”
The difference had to do with time. Obese patients tended to have low but constant levels of IL-6, which caused chronic inflammation. When patients exercised, their IL-6 levels would spike, then dissipate over a few hours. The patients who exercised had much lower baseline levels of inflammation.
Since then, dozens of these myokines have been identified. Febbraio believes there could be hundreds more and that they’re largely responsible for the beneficial effects of exercise. They act on bones, the pancreas (which secretes insulin), and the immune system. Researchers think they may also act on muscle itself, promoting growth and healing, and on the brain, triggering the release of derived neurotrophic factor, which heals and protects neurons.
Wednesday, 19 June 2013
Skeletal Muscle is the Organ that Counteracts Fat
Outside magazine on fat,