The effect of verapamil on cardiovascular and metabolic responses to exercise

In a double-blind cross-over study, the effects of verapamil on the cardiovascular and metabolic changes during a progressive maximal exercise test were studied in 12 healthy volunteers. Each subject was treated with placebo and verapamil in 3 different dosages: 3 X 40, 3 X 80 and 3 X 120 mg X d-1 in random order. Drugs were administered for 2 days; on the 3rd day, 2 h after the last dose, a progressive exercise test until exhaustion was performed on a bicycle ergometer. No significant differences in maximal exercise capacity were found between the 4 groups of medication. VO2, VCO2, and VE were also unaffected by verapamil administration. Heart rate during exercise was reduced dose-dependently (p less than 0.001). With the highest dose of verapamil, maximal heart rate was reduced by 13 +/- 1 beats X min-1. No effect could be shown on parameters of carbohydrate and fat metabolism. Perceived exertion, estimated by the Borg scale, did not differ between placebo and the 3 medication groups. The study shows that despite a distinct reduction of heart rate, maximal exercise capacity remains unaffected after verapamil use.