Aerobic activities like jogging and interval training can make our cells biologically younger; weight training did not have the same effect. By Gretchen Reynolds.
Past studies have shown that exercise alters the workings of many genes, as well as the immune system, muscle-repair mechanisms and many other systems within the body.
Some researchers have speculated that the most pervasive anti-aging effects of exercise may occur at the tips of our chromosomes, which are capped with tiny bits of matter known as telomeres. Telomeres seem to protect our DNA from damage during cell division but, unfortunately, shorten and fray as a cell ages. At some point, they no longer safeguard our DNA, and the cell becomes frail and inactive or dies.
Many scientists believe that telomere length is a useful measure of a cell’s functional age.
But researchers also have found that telomeres are mutable. They can be lengthened or shortened by lifestyle, including exercise. …
There were sizable differences, however, between the groups at a molecular level. Those men and women who had jogged or completed intervals had much longer telomeres in their white blood cells now than at the start, and more telomerase activity.
The weight trainers did not. Their telomeres resembled those of people in the control group, having remained about the same or, in some instances, shortened during the six months.
These results would seem to indicate that exercise needs to be aerobically taxing to extend telomeres and slow cellular-level aging, says Dr. Christian Werner, a cardiologist and researcher at the University of Saarland in Germany, who led the new study. …
The reasons might lie with differences in intensity, he adds. “Even though resistance exercise was strenuous,” he says, “the mean pulse rate was much lower than with running,” resulting in slighter blood flow and probably less physiological response from the blood vessels themselves.