People who are reluctant to exercise could be missing key genes that control muscle protein, Canadian scientists claimed Tuesday.
In tests on mice, researchers from McMaster University in Hamilton, Ontario, found that removing the genes that control the AMP-activated protein kinase (AMPK) left the rodents unable to run as fast as their healthy counterparts.
AMPK is "switched on" with exercise and allows muscles to take up glucose, the researchers wrote in the journal Proceedings of the National Academy of Sciences.
Associate professor of medicine Gregory Steinberg said, ""Mice love to run. 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 study found that mice without the AMPK genes had lower levels of mitochondria, cells' main energy producers, and their muscles' ability to take up glucose during exercise was impaired.
Steinberg added, "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."
The researchers said the findings were important for those who find it difficult to exercise, including the obese and those with asthma.