Serum heat shock protein after simulated deep diving in Navy divers.

Deep sea diving might cause a tremendous physical or psychological stress to the divers. The present study aims to evaluate the stress response to a simulated wet dive in Navy divers. Nineteen Navy divers took part in this study when they were undergoing annual deep dive training. Ten divers were exposed to 190 feet of sea water (fsw) breathing compressed air on day 1 and to 250 fsw breathing helium-oxygen (Heliox) gas mixture on day 3. Another 9 divers were exposed to 220 fsw on day 1 and 285 fsw on day 3 breathing Heliox gas mixture. The bottom time ranged from 5 to 8 min, and then the standard U.S. Navy air and Heliox decompression tables were followed for surfacing. Predive levels of serum heat shock protein 72 (sHsp72) were 9.95 +/- 0.56 ng/ml, which were significantly higher than those in the control group (8.01 +/- 0.77 ng/ml). After simulating Heliox dive, the sHsp72 increased to 10.43 +/- 0.56 ng/ml, but this was not statistically significant. Our results demonstrated that the serum level of Hsp72 is higher in the Navy divers who underwent regular intensive exercise. However, it remains unknown whether this increase of stress protein is associated with the diving stress or exercise preconditioning in the Navy divers.