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

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

Changes in body temperature and basal metabolic rate of the ama

Oral temperatures of Korean diving women (ama) were measured before and after diving work in four seasons of the year. Their basal metabolic rate, measured in four seasons, was compared to that of nondiving women who lived in the same community and ate the same diet as the ama. Average oral temperatures declined to 35 C after 70 min of work in summer (water temp., 27 C) and to 33 C after 15 min of work in the winter (water temp., 10 C). Average body temperature, computed from weighted oral and average skin temperatures, declined to 34.6 C in summer and to 30 C in winter. Duration of work periods was determined principally by water temperature, since oral temperature declined at a rate inversely proportional to water temperature. The lower deep body temperatures which the ama endure in winter do, however, prolong their winter work period. The BMR of nondiving women was the same as the Dubois standard throughout the year. However, the BMR of ama varied with the season, ranging from +5 of the Dubois standard in summer to +35 in winter. We conclude that the elevated BMR of ama during the winter is cold adaptation, induced by repeated immersion in cold water.

Submitted on November 23, 1962

Lung volumes and ventilatory responses to high CO2 and low O2 in the ama

Various respiratory functions were determined in 20 ama (diving women) as well as in an equal number of nondivers (control group.) The vital capacity was significantly larger in the ama than in the control; this is entirely due to the higher inspiratory capacity in the former group. Neither the residual volume (RV) nor the expiratory reserve volume showed any difference between the two groups. Hence, the RV/TLC ratio tended to be lower in the ama. MBC was considerably higher in the ama. The maximal inspiratory pressure for any given lung volume was significantly higher in the ama, while the maximal expiratory pressure was not different between the two groups. The resting alveolar gas composition is not different from that of the control. The ventilatory responses to breathing 3% and 5% CO2 in O2, as well as the ventilatory responses to breathing 8.5% O2 in N2, were measured and are discussed. It is suggested that some of these differences in pulmonary function between the ama and control group represent long-term adaptations of the divers acquired by engaging daily in diving operations.

Submitted on September 28, 1962