Researchers have known for some time that telomeres, DNA-protein complexes at the ends of chromosomes, help protect the body's cells, including reducing the risk of cancer by preventing chromosomes from fusing with each other or rearranging. Emerging evidence also indicates that examining telomere length might help predict risk of certain cancers and that interventions such as stress reduction or exercise might help maintain and perhaps lengthen telomeres.
Hampton T. Studies Probe Role of Telomere Length in Predicting, Modulating Cancer Risk. JAMA. 2011;305(22):2278-2279. doi:10.1001/jama.2011.772