Study reveals how exercise increases metabolic health
21 December, 2020
Intensive exercise boosts communication between skeletal muscles and fat tissue, fine-tuning metabolism and enhancing performance, research in mice and humans suggests. The finding may bring about new treatments for metabolic diseases associated with aging and obesity.
Researchers in Brazil have learned that aerobic fitness exercise triggers the release of signaling molecules in to the bloodstream that free up more energy for use by the muscles.
Previous research has discovered that aging and obesity impair the production of the signaling molecules, referred to as microRNAs. This escalates the likelihood of metabolic diseases, such as for example diabetes and dyslipidemia.
The good news is that exercise can help defend against these conditions by upgrading the production of certain microRNAs.
The new research appears in the journal Proceedings of the National Academy of Sciences of the United States of America.
Treadmill exercise program
Marcelo Mori and his colleagues at the University of Campinas Institute of Biology in São Paulo, Brazil, collaborated on a series of experiments with researchers at the University of Copenhagen in Denmark and Harvard University in Cambridge, MA.
They started by putting mice on a treadmill for 60 minutes each day for eight weeks. As the mice became fitter, the researchers increased the speed and slope of the treadmill.
At the end of the training program, the researchers found a substantial increase in the production of a protein called DICER in the animals’ fat cells. This increase correlated with reductions in the body weight of the mice and the quantity of visceral fat in their abdomens.
DICER is an enzyme that allows fat cells, or adipocytes, to create microRNA signaling molecules. These subsequently make more energy available to the muscles.
When the scientists repeated the test out genetically modified mice that were struggling to make any DICER within their fat cells, the mice didn't benefit as much from working out program.
“The animals didn't lose weight or visceral fat, and their overall fitness didn't improve,” says Mori.
Fat cells in the genetically modified mice failed to supply their muscles with the excess metabolic fuel they needed during strenuous exercise.
Without DICER, says Mori, fat cells actually consume more glucose during exercise, leaving less fuel for muscles. This may bring about hypoglycemia, or low blood sugar. In athletes, this can limit their performance.
High intensity training
In human volunteers who underwent 6 weeks of high intensity interval training, the researchers recorded a fivefold increase typically in the quantity of DICER within their fat tissue.
Exercise boosted DICER levels in both younger participants, whose average age was 36, and older participants, whose median age was 63. However, there is a significant variation between individuals, that could help clarify why some people benefit from exercise more than others.
To confirm that fat and muscle were communicating via signaling molecules in the bloodstream, the researchers injected blood serum from a mouse that had undergone the workout program right into a mouse that hadn't.
This infusion of serum from a fit mouse increased production of DICER in the recipient’s fat tissue.
“This finding suggests trained people have a number of molecules in their bloodstream that directly induce a metabolic improvement in adipose tissue,” explains Mori.
“If we are able to identify these molecules, we are able to investigate if they also induce other benefits associated with aerobic exercise, such as for example [improving heart health],” he adds. “Moreover, we may consider converting this knowledge right into a drug at some stage.”
The team have previously taken a part of this direction by narrowing the field to 1 particular microRNA molecule called miR-203-3p.
They showed that whenever muscles have consumed almost all their own glucose stores during prolonged exercise, miR-203-3p signals the fat tissue to create more fuel available.
“We found this metabolic overall flexibility to be necessary to good health in addition to performance enhancement,” says Mori.
Source: www.medicalnewstoday.com
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