Adaption to High Altitude: Changes in Lung Volumes During the First Seven Days at Mt. Evans, Colorado

Abstract

The vital capacity of four subjects at 14,250 ft. decreased during the first 3 days of a 7-day stay, then progressively increased in all subjects and exceeded sea level values in 2 subjects. The residual volume increased the 1st day, then fell during the next 4 days and had leveled off by the end of the week so that 3 subjects were above values, and 1 subject was just at sea level value. The total capacities were high initially, but by the end of the week 2 subjects had total volumes above those at sea level and 2 below. The expiratory reserve volume increased progressively in all subjects over the first 6 days. Breathing oxygen in all 4 subjects and continuous positive pressure breathing in 2 subjects failed to increase the vital capacity. Certain implications of the lung volume changes, particularly as concerns pulmonary blood volume changes, are discussed.