Comparison of Biochemical Responses Between Single and Repeated Exposures to Air at 6.7 ATA
Abstract
U.S. Navy diver volunteers were subjected to short (45-minute) exposures to air at 6.7 ATA. The experimental protocol was designed to compare the recoveries from single exposures with those from similar dives employing 3- day inter-dive intervals. Serum and 24-hour urine samples were collected for 5 days prior to and for 7 and 10 respectively after the dives. Serum and urinary minerals, electrolytes, and protein metabolites as well as serum enzymes and urinary steroids were measured. The overall effects of air at 6.7 ATA and 19 serum parameters was very pronounced 1 hour post-dive. Following a single dive, the response declined sharply to a low after 3 days. This was followed by a second response peak after 5 days and a subsequent gradual decline. Following the 3-day-repeat dives, a secondary peak occurred on the 3rd day following the second dive. The response to the diving stress as indicated by 14 urine parameters showed a small increase on the first two post-dive days followed by a decrease on the third. After a single dive, the consequences of the exposure continued to increase for up to 7-8 days. When a second dive was made on the 3rd day after the initial exposure, a very large response occurred on the 2nd day after the second dive, with a rebound on the 3rd day, and secondary peaks on the 4th and 6th day. These studies support previous observations that effects of hyperbaric exposure continue for several days following pressurization. Repeated exposures within the recovery period alter the pattern of recovery.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 04, 1975
- Accession Number
- ADA020044
Entities
People
- D. V. Tappan
- E. Heyder
- M. J. Jacey
Organizations
- Naval Submarine Medical Research Laboratory