Italian researchers showed that after running a marathon, a person's lymphocytes live longer (BMC Physiology, May 2010). This could help to explain why exercisers live more than 12 years longer than those who do not exercise (British Journal of Sports Medicine, March 2008).
Every cell in your body has a programmable cell death called apoptosis. For example, skin cells live 28 days and then die. Cells lining the inside of your mouth and intestines live 48 hours, and your red blood cells live 120 days. When cells become cancerous, they live forever. They lose apoptosis and forget to die. Cancer cells then transfer to other tissues to prevent them from functioning. For example, breast cancer cells become so abundant that they may travel to your liver and damage it so you lose liver function. They travel to your brain and you lose brain function. Cancer cells kill by preventing other tissues from functioning in your body.
What would happen if your cells lived longer than they are supposed to, but still retained apoptosis and died, only later than they normally do? Perhaps you would live longer. This study shows that running a marathon prolongs the life of cells by increasing many of the messenger chemicals associated with delayed apoptosis, including SIRT1 (an enzyme that contributes to longevity).
Shortened telomeres (chromosome caps) represent aging. An earlier study showed that fifty-year-old competitive marathon runners have telomeres 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; reported in the February 10 eZine )