Download PDF
Int J Sports Med 1992; 13(1): 74-76
DOI: 10.1055/s-2007-1021239
Short Communication

© Georg Thieme Verlag Stuttgart · New York

Caffeine in Sport. Influence of Endurance Exercise on the Urinary Caffeine Concentration

P. J. van der Merwe, H. G. Luus, J. G. Barnard*
  • Department of Pharmacology and *Department of Human Movement Studies, University of the Orange Free State
Further Information

Publication History

Publication Date:
14 March 2008 (online)

Also available at
  PDF Download  Permissions and Reprints

Abstract

This study was conducted to evaluate the influence of excessive sweating during long-distance running on the urinary concentration of caffeine after the intake of a large amount of caffeine. Nine endurance-trained athletes participated in a randomised cross-over study in which 450 mg caffeine were taken with and without exercise. Exercise consisted of running for 30 min on a treadmill at 75% of maximum heart rate, one hour after intake of caffeine. This endurance exercise caused a decrease in the urine flow as well as in the amount of caffeine excreted in urine. The combined effect of both these decreases is that the concentrations of caffeine detected in urine were similar with and without exercise. The maximum caffeine concentration detected in any urine sample was 11.9 (ig/ml without exercise and 10.4 u.g/ml with exercise. It can be concluded that excessive sweating during long-distance running did not enhance the urinary caffeine concentration.

Key words

Sport - caffeine - endurance exercise