Physical Performance of Uncclimatized Men in Mexico City

Abstract

The physical performances of a swimmer and two accompanying laboratory staff members (normally resident in Toronto, altitude 550 ft.) were studied during a six-day visit to Mexico City (altitude 7,347 ft). Swimming times were below standard at altitude; there was also a decrease of maximum working capacity, a higher pulse rate during submaximal work, and slower recovery of the pulse rate after exercise. Vital capacity in 1.BTPS (liters of gas measured at body temperature and pressure, saturated with water vapor) was unchanged, but forced expiratory volume, maximal midexpiratory flow, and peak expiratory flow rate all showed some increase. The arterial pCO₂ was lower than in Toronto, and the arterial pH was increased, but the standard bicarbonate showed no consistent change. A small increase of red cell count occurred.