The influence of angiotensin converting enzyme and bradykinin receptor B2 gene variants on voluntary fluid intake and fluid balance in healthy men during moderate-intensity exercise in the heat

Appl Physiol Nutr Metab. 2015 Feb;40(2):184-90. doi: 10.1139/apnm-2014-0307. Epub 2014 Oct 22.

Abstract

Angiotensin converting enzyme (ACE) and bradykinin receptor B2 (B2R) genetic variation may affect thirst because of effects on angiotensin II production and bradykinin activity, respectively. To examine this, 45 healthy Caucasian men completed 60 min of cycle exercise at 62% ± 5% peak oxygen uptake in a room heated to 30.5 ± 0.3 °C with ad libitum fluid intake. Blood samples were collected pre-, mid-, and immediately post-cycle. Fluid intake, body mass loss (BML), sweat loss (determined via changes in body mass and fluid intake), and thirst sensation were recorded. All participants were genotyped for the ACE insert fragment (I) and the B2R insert sequence (P). Participants were homozygous for the wild-type allele (WW or MM), heterozygous (WI or MP) or homozygous for the insert (II or PP). No differences between genotype groups were found in mean (±SD) voluntary fluid intake (WW: 613 ± 388, WI: 753 ± 385, II: 862 ± 421 mL, p = 0.31; MM: 599 ± 322, MP: 745 ± 374, PP: 870 ± 459 mL, p = 0.20), percentage BML or any other fluid balance variables for both the ACE and B2R genes, respectively. Mean thirst perception in the B2R PP group, however, was higher (p < 0.05) than both MM and MP at 30, 45, and 60 min. In conclusion, the results of this study suggest that voluntary fluid intake and fluid balance in healthy men performing 60 min of moderate-intensity exercise in the heat are not predominantly influenced by ACE or B2R genetic variation.

Keywords: angiotensin converting enzyme; bradykinin receptor B2; dipsogenic; dipsogène; enzyme de conversion de l’angiotensine; exercice physique; exercise; fluid balance; récepteur B2 de la bradykinine; soif; thirst; équilibre liquidien.

MeSH terms

  • Adolescent
  • Adult
  • Analysis of Variance
  • Bicycling / physiology
  • Drinking Behavior / physiology*
  • Exercise / physiology*
  • Hot Temperature*
  • Humans
  • Male
  • Middle Aged
  • Peptidyl-Dipeptidase A / genetics*
  • Receptor, Bradykinin B2 / genetics*
  • Reference Values
  • Sweating / physiology
  • Water-Electrolyte Balance / physiology*
  • Young Adult

Substances

  • Receptor, Bradykinin B2
  • ACE protein, human
  • Peptidyl-Dipeptidase A