Decompression sickness (DCS) is a complex illness involving various pathological effects on the body caused by bubbles formed during and after SCUBA diving. The suggested risk factors for DCS are many and their influence disputed. Dehydration is one of these risk factors, but hardly any studies have been done covering the relationship between dehydration and DCS in humans. Animal studies are not conclusive and the compatibility to humans questionable.
In this study, 468 divers without DCS symptoms was asked to participate and their hydrationstatus was monitored by taking urine samples and measuring urine specific gravity (USG) before and after diving. Hydration status in patients admitted to Sharm el Sheikh Hyperbaric Medical Centre with symptoms of DCS was measured by the same method. Water consumption during the diving day was documented, together with dive-profiles and individual data (age, sex, height weight etc.).
The results showed that about one third of all divers were dehydrated before diving, but it was, because of hyperbaric diuresis, not possible to state the divers post-diving hydration level utilizing this method. 50 % of the treated DCS patients appeared to be relatively dehydrated. Water consumption was not significantly different in the two groups.
The amount of data is too little and the USG measured post-dive in non-DCS divers are not comparable to USG values in the urine from DCS patients. It is therefore impossible to confirm or exclude dehydration as a risk factor for DCS based on this study. Another study should be conducted based on plasma osmolality in DCS patients with their dive buddies as control group.
The strong theoretical background for dehydration as a risk factor for DCS, together with increased dehydration caused by hyperbaric diuresis, can not be ignored, and all divers, especially in warm climates should be encouraged to stay well hydrated during diving.