Switch found to control exercise response
Ever wonder why some people in your fitness class get a big benefit from both the aerobic and strength training sets while others seem to get an advantage from just one of the workouts?
Researchers at the Boston-based Joslin Diabetes Center may have the answer. In a study, published in the journal Nature Communications, researchers uncovered a molecular “switch” that occurs when a protein that helps to drive the body’s response to exercise, called c-Jun N-terminal kinase (JNK), is activated.
“It’s like a switch,” said Sarah Lessard, lead author of the study. “If the switch is on, you’ll have muscle growth. If it’s turned off, you have endurance adaptation in the muscle.”
Aerobic exercise can help to prevent diabetes, cardiovascular disease and other chronic metabolic diseases. But not everyone gets the same benefits from running, spinning and swimming.
Researchers found that when the JNK biological pathway was turned on in lab mice, they would respond poorly to endurance exercise training. When the scientists knocked out the production of the JNK protein, the mice had a much higher increase in their aerobic exercise capacity as well as higher levels of blood vessels and a type of muscle fibre that would help with endurance.
The researchers repeated the tests on humans and received similar results.