RESUMO
<p><b>OBJECTIVE</b>To investigate whether a simulated He-O2 saturation dive to 65 msw would affect oxidative balance in humans.</p><p><b>METHODS</b>Seven divers participated in a simulated saturation dive to 0.75 MPa (65 msw). 24-h urine samples were collected twice before, twice during, and twice after the dive, then were analyzed for contents of superoxide dismutase (SOD), malondialdehyde (MDA), total amino acid (T-AA) and total anti-oxidant capacity (T-AOC). Meanwhile, total urine volume and body weight were measured.</p><p><b>RESULTS</b>The content of T-AA was higher. (P < 0.05) than the base value in final decompression, but reverse to normal at one week after decompression. There were no changes in contents of SOD, MDA and T-AOC during and after the dive compared with their basic value. Total urine volume was lower (P < 0.05, vs basic value) at first day in chamber, then returned to normal. Body weight gradually increased after compression till the end of decompression (higher than basic value, P < 0.05).</p><p><b>CONCLUSION</b>These data indicate that simulated saturation dive to 65 msw may not induce obvious oxidative damage, but it is necessary to monitor 24-h urine volume and oxidative sress by time in order to prevent from tissue injury.</p>