Athlete Martin Hyman huffs and puffs into the bicyclergometer as he helps Dr Griffith Pugh answer a question worrying sport the world over : Will extreme physical exhertion in a rarified atmosphere be dangerous to athletes competing in the Mexico Olympics ? Pugh , in charge of the testing of six athletes at a Medical Research Laboratory , will carry out heart , lung and other tests , in Mexico to compare with the London results . The Olympic Games will be held in Mexico City , 7000 feet above sea level . 21 October 1965