The Everest marathon is a biannual race run from 5184 m near Everest base camp and finishing in the Sherpa capital of Namche Bazaar at 3446 m. It is recognised as the highest and possibly the toughest marathon race in the world. The runners start at a height at which the atmospheric pressure and inspired oxygen pressure are 50% of the value at sea level.¹ It began in 1987 to an outcry from many altitude experts who felt the risks of running at that altitude were unjustifiable.² However, it has proven to be a safe if tough race. There have been no fatalities. On average over the seven marathons, 5–10% of contestants have been unable to complete the whole race, some completing part of the course.³ In 1995 the course was unsafe because of a heavy snowfall, and only a half marathon was run. The previous races have been held in late November after the monsoon season. This year for the first time it was held in April, a warmer time of year. Daytime temperatures were typically around freezing, falling at night to −10°C.

The main medical problems facing previous medical teams have been altitude sickness, diarrhoea and vomiting, chest infections, and musculoskeletal disorders, especially anterior knee pains, contusions, and blistering of the feet.⁴ Knowledge of previous problems and the use of drug formularies from previous marathons helped to ensure that the expedition was adequately equipped.