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Hemodynamic mechanisms underlying the incomplete tolerance to caffeine's pressor effects.

Farag NH, Vincent AS, McKey BS, Whitsett TL, Lovallo WR

Department of Psychiatry and Behavioral Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. noha-farag@ouhsc.edu

Blood pressure (BP) and cardiovascular hemodynamics were assessed at baseline and after caffeine administration in a 4-week, placebo-controlled, double-blind, randomized, crossover trial of caffeine tolerance formation. Half of the subjects developed tolerance to the pressor effect of caffeine, whereas the other half continued to show increases in BP after caffeine ingestion (F = 16.7, p <0.0001). In the subjects who did not develop tolerance, peripheral resistance increased incrementally as the daily dose of caffeine increased (F = 2.8, p = 0.05).

Published 20 May 2005 in Am J Cardiol, 95(11): 1389-92.
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