Researchers monitored people’s heart rates during their workouts, and the exercisers continued their programs for six months. Afterward, everyone returned to the lab, where the scientists again tested fitness and drew blood.
At this point, the volunteers who had exercised in any way were more aerobically fit.
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.
“In the parameters we looked at, endurance exercise was clearly ahead of resistance training,” he says.
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. Those who did resistance training would have produced less of a substance, nitric oxide, that is thought to affect the activity of telomerase and contribute to lengthening telomeres.
But the findings do not indicate that weight training does not combat aging, he says. Like the other workouts, it improved people’s fitness, he says, which is one of the most important indicators of longevity.
Over all, he says, the results underscore that differing types of exercise almost certainly lead to potentially synergistic impacts on our cells and bodily systems. In future studies, he and his colleagues would like to study the cellular effects of various combinations of endurance and strength training.
But for now, the message of the new study, he says, is that exercise of any kind may change the nature of aging, even for people who already are middle-aged. “It is not too late,” he says, “to keep your cells young.”
Source : Nytimes
