Maximal Physical-Work Capacity of Man at 43.4 ATA.

摘要

Four U. S. Navy divers performed submaximal and maximal work in 4.4 C water on an underwater-cycle ergometer at 1.6 and 43.4 ATA (1400 fsw). The VO sub 2 max (VO sub 2 at the maximally tolerated 6-min work load) under control conditions at 1.6 ATA was 2.86-3.00 liter/min in three divers, and decreased to 1.81 - 2.36 liter/min at the maximal depth. The fourth diver increased his VO sub 2 max from 1.53 liter/min at 1.6 ATA to 1.90 liter/min at 43.4 ATA. Reductions in maximal external-work performance on the ergometer averaged 30% at depth; measured work performance on the ergometer averaged 30% at depth; measured work on the ergometer was generally restricted to 75 watts or less. End-tidal P sub CO2 increased concordantly with VO2 AT DEPTH BUT DID NOT exceed 50 MMHg. Carbon dioxide retention was not a significant factor in work limitation. The VE during maximal work did not remain a fixed percentage of the maximum voluntary ventilation (MVV) at 43.4 ATA, but there was no consistent tendency for the divers to respire nearer their MVV. Dyspnea was severe at depth during exercise and the perceived effort expanded to breathe was at the extreme limit for each man.