Renal response to head-out water immersion in Korean women divers

Head-out water immersion (HOI) induces a profound diuresis and natriuresis, which may endanger the body fluid balance of breath-hold divers during prolonged diving work. To investigate if adaptation is acquired by professional breath-hold divers, we have evaluated renal responses to 3-h HOI in 5 Korean women divers (Amas) and 11 nondiving housewives (controls). In both control and diver groups, the average urine flow during 3-h immersion was four times greater and Na+ excretion was 70%-80% greater than the pre-immersion value [urine flow: 3.7 (SD 1.0) ml.min-1 vs 0.9 (SD 0.4), P < 0.001, in controls; 4.3 (SD 0.9) vs 1.1 (SD 0.4), P < 0.001, in divers; Na+ excretion: 270 (SD 176) mumol.min-1 vs 161 (SD 84), P < 0.025, in controls; 303 (SD 31) vs 164 (SD 62), P < 0.005, in divers]. In all cases, the values for a given period were not significantly different between the two groups. The plasma concentrations of Na+ and osmolality, and renal clearance of creatinine did not change significantly. However, the osmolal clearance increased [from 2.0 (SD 0.8) ml.min-1 to 2.8 (SD 0.7), P < 0.05, in the controls; from 2.2 (SD 0.4) to 2.6 (SD 0.4), P < 0.05, in the divers] and free water clearance changed from negative to positive values [from -1.1 (SD 0.5) ml.min-1 to 1.2 (SD 0.3), P < 0.005, in the controls; from -1.2 (SD 0.4) to 1.6 (SD 1.1), P < 0.01, in the divers] during immersion, again the pattern of change being similar in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)