June 2006

Vol. 21, No. 6     What's this?

Does Dehydration Increase the Risk for DCS?

from the June, 2006 issue of Undercurrent  

Dehydration is often considered a contributor to decompression sickness (DCS), because hydration may enhance inert gas removal or increase surface tension of the blood. However, it’s not been studied.

Now, in a study with pigs published in the Journal Aviation, Space and Environmental Medicine by Fahlman and Dromsky at the Naval Medical Research Center, they have shown that there is an increased risk for DCS due to dehydration.

Dehydration increased the overall risk of severe DCS and death. It increased the risk of cardiopulmonary DCS, and showed a trend toward increased central nervous system DCS. In addition, dehydrated subjects manifested cardiopulmonary DCS sooner and showed a trend toward more rapid death.

Male Yorkshire pigs were compressed on air to 110 ft of seawater for 22 hours and brought directly to the surface at a rate of 30 fsw/min. The hydrated group was allowed access to water during a simulated saturation dive. The dehydrated group received intravenous diuretic medication and were not allowed access to water throughout the dive.

Of the 31 hydrated pigs, nine had cardiopulmonary DCS, eight central nervous system CNS, and four died. In the dehydrated group of 26, nineteen had cardiopulmonary DCS, six had CNS, DCS, and nine died.

The researchers concluded that in this study, hydration status at the time of decompression significantly influenced the incidence and time to the onset of DCS.

For the diver this means drink plenty of water before and between dives. That it increases your need to urinate is no excuse not to hydrate yourself. The early signs of dehydration include a flushed face, dizziness made worse when you’re standing, weakness, dry mouth, or cramping in the arms and legs.

Check the color of your urine to detect if you’re adequately hydrated. The darker yellow it is, the more likely you’re dehydrated.