HANA-KAI-II - 17-DAY DRY SATURATION DIVE AT 18.6 ATA .2. ENERGY-BALANCE

Abstract

Since previous saturation dives have caused loss of body weight despite apparently adequate-to-high food intake, a complete study of energy balance was undertaken during the saturation dive Hana Kai II. Over a 30 day period in the hyperbaric chamber (3 days of predive control, 1 day of compression, 16 days at 18.6 ATA [atmospheres absolute pressure] 7 days of decompression and 3 days of postdive control), all food, urine and feces for 5 men were analyzed by bomb calorimetry; 24 h energy expenditure (M) was measured from continuous .ovrhdot.VO2[O2 consumption], .ovrhdot.VCO2[CO2 production], and urine N. Body weight was taken daily; body composition was assessed from density, total body water and skinfold thickness. Food intake was high throughout the 30 days (about 3500 kcal/day) while fecal and urinary losses were a normal 6-8% of intake. Energy expenditure was increased a little by the hyperbaric condition, but averaged only 2431 kcal/day for the 30 days and yet there was an average loss of adipose tissue of 0.8 kg for each man for the entire period. N balance was positive. There was no evidence of heat gain or loss. The energy balance, total fuel compared with energy expenditure, required an additional 919 kcal/man-day for 30 days, an unidentified term which is not measured by conventional techniques.