Researchers in Homburg, Germany showed that 50-year-old men who ran more than 50 miles per week at a fast pace had telomeres (chromosome caps) that were almost the same length as those of 20-year-old runners on the German National Team, and more than 40 percent longer than those or inactive men of the same age (Circulation, December 2009). This is astounding because shortened telomeres represent aging.The active ends of the genetic material (chromosomes) in cells are covered with a layer of proteins called telomeres. If they weren't, the exposed ends of the genetic material would stick to anything nearby and the cells would die. However, each time a cell divides to make two cells, a little bit of the telomere is removed. Eventually the telomere...