Lactic Acid in Rest and Work at High Altitude1

The present paper sets forth blood lactic acid values obtained from four groups of subjects at high altitude: members of our party in Chile, residents of ‘Quilcha, Chile (altitude 5.34 km.), members of our party at Leadville, and residents at Leadville. The Chilean party was divided into two groups. The first group, consisting of six men, was engaged for approximately six weeks setting up a mobile laboratory at Chuquicamata at an altitude of 2.81 km. A regular program of work on a bicycle ergometer, mountain climbing, and long walks was followed during this period. The second party from sea level, four men, then joined the first, and observations were immediately begun. The concentration of lactic acid was determined both in arterial blood drawn in the morning before rising and in blood drawn from the antecubital vein after measured performances on the bicycle ergometer. There were 16 days of observations at an altitude of 2.81 km., 8 days at 3.66 km., 12 days at 4.70 km., and 3 weeks at 5.34 km. During this last period parties of two spent from 1 to 6 days at 6.14 km., the top camp. Lactic acid was determined in blood obtained in rest at this altitude, but it was not feasible to transport the ergometer for exercise studies. Values in rest were obtained on six residents at 5.34 km., five of whom were laborers at the sulphur mine, 5.70 km. The Leadville party consisted of eight members who spent from one to two months at 3.0 km. altitude. Three members spent four days on the top of Mt. Elbert, 4.39 km. Resting lactic values only are presented for