A study found that exercise aids in the release of a peptide that increases physical endurance and the muscle's energy production. Skeletal muscles release an "exercise hormone" called musclin as a response to the activity. When released in the bloodstream, musclin supports harder and longer exercise routines.
Findings showed high levels of circulating musclin in the bloodstream trigger signals that improve muscle performance. More musclin also increases mitochondria production in muscle cells, Mitochondria is a cell's powerhouse.
"We don't want to replace exercise by using this exercise factor, but if we can learn more about the mechanism, it might help us to increase exercise tolerance and make it easier for people to actually exercise," said senior author Dr. Leonid Zingman, an internal medicine associate professor at the University of Iowa's Carver College of Medicine.
The research team used genetically modified mice who can't produce musclin. While they look like regular lab mice, their exercise tolerance is relatively lower. These mice are unable to exercise harder and longer as the ones in the control group.
The team infused musclin back and documented how effective the peptide was in restoring the animal's ability to workout in one week, added Ekaterina Subbotina, Ph.D., a Zingman's laboratory post-doctoral scholar.
When the knocked out mice were infused with musclin, the peptide also increased the lab tests' treadmill activity. Without prompting, they ran longer and faster compared to the control group who received a placebo saline infusion. The findings linked increase mitochondria production to higher exercise capacity in the test mice.
The study focused on exercise' effect on musclin levels. The team documented that even when the subjects were inactive, the musclin-lacking mice showed lower endurance and exercise levels compared their counterparts in the control group. The findings suggest musclin can also stimulate muscle health even during low exercise and normal activities.
Zingman, who is also Iowa City Veterans Affairs Medical Center's physician scientist, stressed that if exercise becomes easier, more people will do it. The study was published in the journal Proceedings of the National Academy of Sciences Early Edition on Dec. 14.
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