Dose-dependent effect of caffeine on reducing leg muscle pain during cycling exercise is unrelated to systolic blood pressure

This double-blind, within-subjects experiment examined the effects of ingesting two doses of caffeine on perceptions of leg muscle pain and blood pressure during moderate intensity cycling exercise. Low caffeine consuming college-aged males (N = 12) ingested one of two doses of caffeine (5 or 10 mg(.)kg(-1) body weight) or placebo and 1 h later completed 30 min of moderate intensity cycling exercise (60% (V)over dot (O2peak)). The order of drug administration was counter-balanced. Resting blood pressure and heart rate were recorded immediately before and 1 h after drug administration. Perceptions of leg muscle pain as well as work rate, blood pressure, heart rate, and oxygen uptake ((V)over dot (O2)) were recorded during exercise. Caffeine increased resting systolic pressure in a dose-dependent fashion but these blood pressure effects were not maintained during exercise. Caffeine had a significant linear effect on leg muscle pain ratings [F(2,22) = 14.06; P < 0.0001; eta(2) = 0.56]. The mean (+/-SD) pain intensity scores during exercise after ingesting 10 mg.kg-1 body weight caffeine, 5 mg.kg-1 body weight caffeine, and placebo were 2.1 +/- 1.4, 2.6 +/- 1.5, and 3.5 +/- 1.7, respectively. The results support the conclusion that caffeine ingestion has a dose-response effect on reducing leg muscle pain during exercise and that these effects do not depend on caffeine-induced increases in systolic blood pressure during exercise. (C) 2004 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.