A German study reports that 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. Over a person’s life span, cells continue to divide, shortening the telomeres. When the telomeres get too short, the cell stops dividing and the person begins to show signs of aging.
In the study, 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 (control group). The athletes included professional runners with an average age of 20 years 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 years) who had done endurance exercise since youth and ran an average of nearly 50 miles a week. The study found that the athletes 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,” stated study author Dr. Ulrich Laufs, a professor of clinical and experimental medicine in the department of internal medicine at Saarland University in Homburg.
The study findings were released online November 30 in advance of publication in an upcoming print issue of Circulation. The primary role of white blood cells was traditionally thought to be fighting off infections, but more recent research has shown white blood cells do much more, including continuously seeking out abnormal cell growths, such as those that cause cancer, and clearing them away. One reason why cancer rates increase with age could be that the white blood cells themselves age, and become less efficient at dealing with the abnormal growths. If exercise maintains the youthfulness of the white blood cells by preventing the shortening of the telomere, it may explain why exercise can protect against developing cancer. Likewise, with heart disease, aging white blood cells (along with high blood pressure and other factors) may allow plaques to accumulate more quickly. By keeping white blood cells young, exercise may enable them to continue to efficiently clear away plaques. Exactly how much exercise is needed to prevent telomere shortening is not known, but the best advice is to do some type of exercise regularly.
In addition to testing human white blood cells, researchers also used mice to study the impact of exercise on proteins that have been implicated in heart disease and cancer. The researchers found that the mice with access to a running wheel for 3 weeks showed increased activity of tumor-suppressing proteins and proteins that play a role in telomere length.
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