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European Journal of Applied Physiology

, Volume 85, Issue 3–4, pp 250–258 | Cite as

Comparison of passive heat or exercise-induced dehydration on renal water and electrolyte excretion: the hormonal involvement

  • Bruno Melin
  • Nathalie Koulmann
  • Chantal Jimenez
  • Gustave Savourey
  • Jean-Claude Launay
  • Jean-Marie Cottet-Emard
  • Jean-Marc Pequignot
  • Anne-Marie Allevard
  • Claude Gharib
Original Article

Abstract.

The effects of hydromineral hormones and catecholamines on renal water and electrolyte excretion were examined during and after dehydration induced by either passive heat or exercise. Eight healthy young Caucasian subjects participated in three separate trials, each including three consecutive phases. Phases 1 and 3 involved a 90-min period at rest in a thermoneutral environment, while phase 2 involved a 120-min period designed to provide: (1) euhydration (control trial), (2) passive heat-induced dehydration of 2.8% body mass, or (3) exercise-induced dehydration of 2.8% body mass. During the two dehydration procedures, the decreases in urine flow and sodium excretion were more marked during exercise (P<0.05). An increase in plasma catecholamines occurred only during exercise, together with a reduction in creatinine clearance and more marked increases in plasma renin and aldosterone than during passive heat exposure (P<0.05). Although plasma vasopressin was elevated during the two dehydration procedures, urine osmolality did not change and, moreover, free water clearance increased during exercise (P<0.05). Plasma levels of atrial natriuretic peptide increased markedly only during exercise compared to the other trials (P<0.05). After the dehydration procedures, urine flow decreased again and urine osmolality increased markedly (P<0.05), while plasma vasopressin remained elevated. These results suggest that sympatho-adrenal activation during exercise plays a major role in the more marked reduction in diuresis and natriuresis than during passive heat exposure. Despite high plasma vasopressin concentrations during the two dehydrating events, the observed antidiuresis was not due to an increased renal concentrating ability, and the vasopressin was more effective after the dehydration procedures.

Dehydration Catecholamines Fluid-regulating hormones Renal responses 

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Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  • Bruno Melin
    • 1
  • Nathalie Koulmann
    • 1
  • Chantal Jimenez
    • 1
  • Gustave Savourey
    • 2
  • Jean-Claude Launay
    • 2
  • Jean-Marie Cottet-Emard
    • 3
  • Jean-Marc Pequignot
    • 4
  • Anne-Marie Allevard
    • 3
  • Claude Gharib
    • 3
  1. 1.Unité de Bioénergétique et Environnement, Centre de Recherches du Service de Santé des Armées "Emile Pardé", BP 87, 38702 La Tronche Cedex, France
  2. 2.Unité de Thermophysiologie, Centre de Recherches du Service de Santé des Armées "Emile Pardé", BP 87, 38702 La Tronche Cedex, France
  3. 3.Laboratoire de Physiologie de l'Environnement, Faculté de Médecine Grange Blanche, 69373 Lyon Cedex 08, France
  4. 4.UMR 5578 CNRS, Faculté de Médecine Grange Blanche, 69373 Lyon Cedex 08, France

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