Fox made no promises that his efforts would lead to a cure for cancer, but he closed his letter with the statement: "We need your help. The people in cancer clinics all over the world need people who believe in miracles. I am not a dreamer, and I am not saying that this will initiate any kind of definitive answer or cure to cancer. I believe in miracles. I have to." The Cancer Society was skeptical of his dedication, but agreed to support Fox once he had acquired sponsors and requested he get a medical certificate from a heart specialist stating that he was fit to attempt the run. Fox was diagnosed with left ventricular hypertrophy – an enlarged heart – a condition commonly associated with athletes. Doctors warned Fox of the potential risks he faced, though they did not consider his condition a significant concern. They endorsed his participation when he promised that he would stop immediately if he began to experience any heart problems.