A variant within the AQP1 3ʹ-untranslated region is associated with running performance, but not weight changes, during an Ironman Triathlon

Abstract

The objective of this study was to test the association of the rs1049305 (G > C) variant within the 3ʹ-untranslated region of the aquaporin 1 gene, AQP1, with changes in body weight, post-race serum sodium concentration and performance in Ironman triathletes. Five hundred and four male Ironman triathletes were genotyped for the rs1049305 variant within the AQP1 gene. Change in pre- and post-race body weight was calculated for 470 triathletes and used as a proxy for changes in body fluid during the race, as well as to divide triathletes into biologically relevant weight-loss groups (0–3%, 3–5% and >5%). There were no rs1049305 genotype effects on post-race serum sodium concentrations (P = 0.647), pre-race weight (P = 0.610) nor relative weight change during the Ironman Triathlons (P = 0.705). In addition, there were no significant differences in genotype (P = 0.640) nor allele (P = 0.643) distributions between the weight loss groups. However, triathletes who carry a C-allele were found to complete the 42.2-km run stage faster (mean 286, s = 49 min) than triathletes with a GG genotype (mean 296, s = 47 min; P = 0.032). The AQP1 rs1049305 variant is associated with running performance, but not relative body weight change, during the 2000, 2001 and 2006 South African Ironman Triathlons.

Keywords:

• athletic performance
• aquaporin 1
• body fluids
• water channel proteins

Acknowledgement

The authors acknowledge Claire Steward for her contribution to genotyping the participants included in this study.

Additional information

Funding

This research was supported by funding gratefully received from the South African National Research Foundation (NRF), South African Medical Research Council, University of Cape Town and Discovery Health. The NRF grant holder acknowledges that opinions, findings and conclusions or recommendations expressed in any publication generated by NRF supported research are that of the author(s), and that the NRF accepts no liability whatsoever in this regard.