Couch potatoes may lack 'exercise genes'Affects key muscle enzyme
Couch potatoes who find it difficult to exercise may lack specific genes, a study has found.
Scientists working on mice removed two of the genes in muscle essential for exercise and found the otherwise healthy animals could not run as far as unaltered mice.
"Mice love to run," said study leader Professor Gregory Steinberg, at McMaster University in Canada.
"While the normal mice could run for miles, those without the genes in their muscle could only run the same distance as down the hall and back.
"It was remarkable. The mice looked identical to their brothers or sisters but within seconds we knew which ones had the genes and which one didn't."
The genes removed from the mice controlled a protein called AMP-activated protein kinase (AMPK), an enzyme that is switched on when you exercise.
The researchers found the mice without the muscle AMPK genes had lower levels of mitochondria - the cell's energy provider - and an impaired ability for their muscles to take up glucose during exercise.
"When you exercise you get more mitochondria growing in your muscle. If you don't exercise, the number of mitochondria goes down.
"By removing these genes we identified the key regulator of the mitochondria is the enzyme AMPK," said Professor Steinberg.
He said the findings are important for individuals who find it difficult to exercise, such as people who are obese, asthmatics and those in wheelchairs, as their inability to exercise may lead to other complications such as diabetes and heart disease.
"As we remove activity from our lives due to emerging technology, the base level of fitness in the population is going down and that is reducing the mitochondria in people's muscles.
"This in turn makes it so much harder for people to start exercising," the Professor Steinberg said.
The study is published in the current issue of the Proceedings of the National Academy of Sciences.
This article was published on Tue 6 September 2011
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