Grunsfeld appeared on the PBS NOVA episode Deadly Ascent, which showed him climbing Denali, the highest peak in North America, in June 2000. Grunsfeld, along with Howard Donner, (a consultant to NASA) conducted research into the effects of body temperature at high altitudes by using internal thermometers swallowed in pill form. He was able to climb to an altitude of 17,200 feet before acute altitude sickness forced him to turn back. Grunsfeld was inspired by Edmund Hillary in mountaineering.