Summary
In this study, the effect of head out water immersion on cardiopulmonary function was investigated in six healthy male subjects. Resistance to breathing, pulmonary capillary volume, and cardiac output increased during immersion. Constancy was observed for shunt perfusion, diffusing capacity, and diffusing capacity of the membrane. Carbon monoxide transfer factor (T CO) in relation to alveolar volume (VA) increased significantly. Due to nonuniform distribution of ventilation during immersion, PaO2 dropped during immersion while AaDO2 increased significantly. The described changes are due to the blood shift and hydrostatic pressure during immersion to the neck. The functional changes counteract each other, partly worsening and partly improving cardiopulmonary function. However, in summary, respiratory and circulatory function are slightly reduced during head out water immersion.
Key words
diving - swimming - weightlessness - cardiopulmonary function
