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?
at the Boston-based Joslin Diabetes Center may have found the
study published in the journal Nature Communications,
researchers uncovered a molecular "switch" that
occurs when a protein that helps to drive the bodyís
response to exercise, called c-Jun N-terminal kinase (JNK), is
like a switch," said Sarah Lessard, lead author of the
study. "If the switch is on, youíll have muscle growth.
If itís turned off, you have endurance adaptation in the
aerobic exercise helps prevent diabetes, cardiovascular
disease, and other chronic metabolic diseases. But not
everyone gets the same benefits from running, spinning,
swimming, and other cardio-boosting exercises.
found that when the JNK biological pathway was turned on in
lab mice, they would respond poorly to endurance exercise
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 fiber that would help with endurance compared with
researchers also repeated the tests on humans and received
similar results. While lifting weights, researchers found JNK
was activated in the leg muscles. But when the subjects cycled
on a bike, an endurance exercise, JNK generally was not
study results have direct implications for the treatment of
Type 2 diabetes.
researchers are now looking at ways to inhibit JNK activation.
over-activation of the JNK pathway during endurance exercise
does indeed boost the risk of diabetes, and if scientists can
figure out a way to stop that process, "we might be able
to reverse the risk in some people," said Lessard,
assistant investigator of clinical, behavioral, and outcomes
research at Joslin.