Nevola, V. R., Weller, A. S., & Harrison, M. H. (1999). Cardiovascular effects of a combined dose of caffeine and ephedrine in man. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 448.

A combined dose of caffeine and ephedrine (C+E) increases time to exhaustion during high intensity exercise and energy expenditure during immersion in cold water. Cardiovascular responses must be understood before C+E can be employed as a performance enhancer. High blood pressure could result from using such hypertensive drugs in combination with known cardiovascular stresses. This investigation evaluated the effects of C+E at rest and during incremental cycling exercise using male (N = 11) volunteers who performed twice, three days apart, one with C+E and the other with a placebo.

Compared to the placebo condition, C+E elevated systolic blood pressure, depressed diastolic blood pressure, and increased heart rate and peak heart rate. Ratings of perceived exertion were continually lower in the C+E condition. These responses were most marked at the highest level of exercise intensity. Elevated cardiovascular factors were masked by the hypertensive effects of exercise.

Implication. Caffeine and ephedrine have a positive ergogenic effect on moderate to high intensity exercise.

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