Exercise Guards White Blood Cells Against Aging

Dec. 1 -- MONDAY, Nov. 30 (HealthDay News) -- Studies have shown that exercise can help ward off heart disease and cancer, and now new research shows that the reason why may be found within cells themselves.

Endurance athletes had longer telomeres -- DNA at the tips of chromosomes that protect the cell -- in their white blood cells than healthy, nonsmoking adults who did not exercise regularly, German researchers report.

Telomeres can be thought of as the plastic tips on the end of shoelaces, which prevent the lace from fraying, explained Emmanuel Skordalakes, an assistant professor of gene expression and regulation at The Wistar Institute in Philadelphia.

Over the life span, cells continue to divide. Each time a cell divides, the telomere is shortened. When the telomere gets too short, the cell stops dividing. When this happens, people age -- gradually losing muscle strength, skin elasticity, vision, hearing and mental abilities, and so on, Skordalakes said.

In the study, the researchers measured the length of white blood cell telomeres of endurance athletes and compared them to the telomeres of age-matched healthy nonsmokers who typically exercised less than one hour a week (the control group). Athletic participants included professional runners with an average age of 20 who ran more than 45 miles a week as part of the German National track and field team. A second group of athletes were middle-aged (average age 51) who had done endurance exercise since youth and ran an average of nearly 50 miles a week.

Not surprisingly, the athletes had a slower resting heart rate -- a sign of cardiovascular fitness -- as well as lower blood pressure, lower body mass index and lower cholesterol than those in the control group.

But the athletes also had longer telomeres than those who were of similar age but did not exercise, and the athletes showed increased activity of the enzyme telomerase, which maintains the telomere.

"This is direct evidence of an anti-aging effect of physical exercise," study author Dr. Ulrich Laufs, a professor of clinical and experimental medicine in the department of internal medicine at Saarland University in Homburg, said in a statement.