Respiratory responses of underwater swimmers to oxygen

¹ Neurophysiology Branch, Naval Medical Research Institute, National Naval Medical Center, Bethesda, Maryland

The respiratory effects of oxygen at atmospheric pressure in laboratory personnel and trained underwater swimmers were studied with the subjects resting in the supine position. The breathing of oxygen for 10 minutes by both groups was associated with a significant depression of respiratory rate and inspiratory minute volume and no significant alteration in end-tidal carbon dioxide tension. The oxygen consumption of the swimmers was significantly greater than that of the laboratory personnel. The swimmers had lower oxygen ventilation equivalents suggesting that they respired more efficiently than the laboratory personnel.