Preliminary Diet and Hydration Guidelines for Diving to Depths to 150 FSW

This report provides a brief review of dietary and hydration changes associated with immersion and hyperbaric exposures to a depth of 150 feet seawater fsw, and recommendations for ensuring adequate fluid and caloric status. Significant loss of body fluid will occur with immersion. Fluid replacement during immersion does not totally reverse this finding. Adequate predive hydration is required, especially in hot environments, and can be judged adequate if the urine is pale in color. For exposures lasting longer than 3 h it is recommended that 500 ml of fluid be ingested per hour. Although this will not reverse the effects of immersion diuresis, it may help prevent significant dehydration and the potential for cardiovascular collapse upon exiting the water. Predive diets should provide 40-50 kcalkgday 3200-4000 kcal per day. A minimum of 50 of the calories should be derived from carbohydrate, and fat intake limited to about 30 of the calories. Similar diets should be used during saturation dives and postdive periods. Repetitive dives occurring with less than a 24-hour surface interval require 600 grams of carbohydrate per day to replenish body glycogen stores. Caloric supplementation during immersion may be required for dives lasting 3 h. This can be achieved by ingesting 250-500 ml per hour of a solution containing 17-34 gm carbohydrate 7 glucose polymer solution. The osmolality of beverages consumed should be less than 260 mOsm to minimize occurrence of gastrointestinal disturbances.