From The Desk Of Clarence Bass
Weight Training Triggers Immediate Fat Burn
Bodybuilding mice are being called on once again. Researchers from the Universities of Kentucky and Nebraska and other institutions needed their help in examining the short term impact of weight training on fat cells.
We’ve long known that muscle mass drives metabolism; the more muscle we have the more calories we burn at rest. That’s the long term effect of muscle on fat burning.
We also know that muscles "talk" to all parts of the body:
Co-senior author John J. McCarthy, a professor of physiology at the University of Kentucky, and his team probed fat burn immediately after muscular overload.
Details of the study--they are fascinating--can be found in an article by Gretchen Reynolds published July 21, 2021, in the New York Times.
The Abstract of the study can be accessed online. We’ll warn you that it’s filled with technical jargon.
You can also find an informative overview by Nick Lavars on New Atlas:
Clearly, there is a good deal of interest in this study.
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Muscular mice were key players. As you will see, it is highly unlikely that they were willing participants.
“To our knowledge, this is the first demonstration of how weight training initiates metabolic adaptations in fat tissue, which is crucial for determining whole-body metabolic outcomes,” says Professor John McCarthy. “The ability of resistance exercise-induced extracellular vesicles to improve fat metabolism has significant clinical implications.”
Through follow-up experiments on human tissue, the scientists found similar signaling processes to be at play, leading them to suspect the same effects of resistance training "may be operative in humans."
Gretchen Reynolds explains how this was done in language we can all understand. The role of the mice is ingenious--and not something humans would abide.
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They incapacitated several of the leg muscles in healthy adult mice, leaving a single muscle to carry all the physical demands of movement. That muscle swiftly gained in size and strength, providing an accelerated version of resistance training.
Before and after that process, the researchers carefully examined the molecular changes in the tissues.
They noted plenty. Before their improvised weight training, the rodents’ leg muscles had teemed with a particular snippet of genetic material, known as miR-1, that modulates muscle growth. In normal, untrained muscles, miR-1, one of a group of tiny strands of genetic material known as microRNA, keeps a brake on muscle building.
After the rodents’ resistance exercise, which consisted of walking around, though, the animals’ leg muscles appeared depleted of miR-1. At the same time, the vesicles in their bloodstream now thronged with the stuff, as did nearby fat tissue. It seems, the scientists concluded, that the animals’ muscle cells somehow packed those bits of microRNA that retard hypertrophy into vesicles and posted them to neighboring fat cells, which then allowed the muscles immediately to grow.
But what was the miR-1 doing to the fat once it arrived, the scientist wondered? To find out, they marked vesicles from weight trained mice with a florescent dye, injected them into untrained animals, and tracked the flowing bubbles’ paths. The vesicles homed in on fat, the scientists saw, then dissolved and deposited their miR-1 cargo there.
Soon after, some of the genes in the fat cells went into overdrive. These genes help direct the breakdown of fat into fatty acids, which other cells then can use as fuel, reducing fat stores. In effect, weigh training was shrinking fat in mice by creating vesicles in muscles that, through genetic signals, told the fat it was time to break itself apart.
Mice are not people, though. So, as a final facet of the study, the scientists gathered blood and tissue from healthy men and women who had performed a single, fatiguing lower-body weight workout and confirmed that, as in mice, miR-1 levels in the volunteers’ muscles dropped after their lifting, while the quantity of miR-1- containing vesicles in their bloodstreams soared.
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“The process was just remarkable,” said Professor McCarthy.
With the help of the mice, willingly or not, the results serve as a bracing reminder that “muscle mass is vitally important for metabolic health,” McCarthy said, and that we start building that mass and getting our tissues talking every time we hoist a weight.
We’ve come a long way from the time when my high school coach warned me that “athletes don’t lift weights.”
This fuzzy photo was lifted from of an article in The Albuquerque Tribune
saying "Bass is strongest."
Weight training also helped me stay lean in the decades to follow.
September 1, 2021
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