Journal of Applied Physiology, Vol 66, Issue 1 34-41, Copyright © 1989 by American Physiological Society
Prolonged whole-body cold water immersion: fluid and ion shifts
P. A. Deuster, D. J. Smith, B. L. Smoak, L. C. Montgomery, A. Singh and T. J. Doubt
Department of Military Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799.
To characterize fluid and ion shifts during prolonged whole-body immersion,
16 divers wearing dry suits completed four whole-body immersions in 5
degrees C water during each of two 5-day air saturation dives at 6.1 msw.
One immersion was conducted at 1000 (AM) and one at 2200 (PM) so that
diurnal variations could be evaluated. Fifty-four hours separated the
immersions, which lasted up to 6 h; 9 days separated each air saturation
dive. Blood was collected before and after immersion; urine was collected
for 12 h before, during, and after immersion for a total of 24 h. Plasma
volume decreased significantly and to the same extent (approximately 17%)
during both AM and PM immersions. Urine flow increased by 236.1 +/- 38.7
and 296.3 +/- 52.0%, urinary excretion of Na increased by 290.4 +/- 89.0
and 329.5 +/- 77.0%, K by 245.0 +/- 73.4 and 215.5 +/- 44.6%, Ca by 211.0
+/- 31.4 and 241.1 +/- 50.4%, Mg by 201.4 +/- 45.9 and 165.3 +/- 287%, and
Zn by 427.8 +/- 93.7 and 301.9 +/- 75.4% during AM and PM immersions,
respectively, compared with preimmersion. Urine flow and K excretion were
significantly higher during the AM than PM. In summary, when subjects are
immersed in cold water for prolonged periods, combined with a slow rate of
body cooling afforded by thermal protection and enforced intermittent
exercise, there is diuresis, decreased plasma volume, and increased
excretions of Na, K, Ca, Mg, and Zn.
