Diving pattern, lung volumes, and alveolar gas of the Korean diving woman (ama)

Abstract

Lung volumes and alveolar gases during actual dives were studied in the Korean diving women, or ama. These women dive without assistance. Average descent and ascent velocities are 0.6 m/sec. Maximal depth and duration of dive observed were 17 m and 82 sec, respectively. However, typical sustained diving activity is to a depth of 5 m for 30 sec, averaging 60 dives/hr. This diving pattern is compared with the assisted dives of the Japanese ama lasting 60 sec and reaching a depth of about 20 m. Prior to diving the lung is filled to 85% of vital capacity. About 700 ml of this gas are lost upon return to the surface. A slight hyperventilation before dive reduces the Pco2 to 28. At the bottom the fractional composition of O2 as well as CO2 is less than before dive indicating that both gases are removed by the circulation. The compression of the gases accounts for the reversal of CO2 transport. Upon return to the surface CO2 leaves the blood and reaches normal values while the O2 is very low. At the bottom O2 pressure is high due to compression but falls rapidly upon ascent. The detailed pattern of gas exchange is discussed. Submitted on September 28, 1962