Caffeine, Ephedrine and their Combination: Effects on Blood Pressure and Heart Rate

摘要

The ingestion of a combination of caffeine and ephedrine has an ergogenic effect on physical performance. Before recommending tactical applications of such a treatment the health risks must be determined. Therefore, it was the purpose of this study to clarify the effects of an acute ingestion of caffeine, ephedrine and their combination on heart rate and blood pressure variables. Twenty male and female subjects had their resting blood pressure and heart rate measured before and throughout 48 hours after ingesting either caffeine (c) (375 mg), ephedrine (E) (75 mg), c+e, or a placebo (p). Treatments were randomized and double blind. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured pre ingestion, 1, 3, 5, 8, 24, and 48 hours post ingestion. Venous blood samples were also obtained at these times and analyzed for caffeine and ephedrine level. All measured variables were significantly increased by the treatments. SBP increased the most after the c+e treatment, approached hypertensive values at the I hour mark (138 mm Hg), decreased thereafter, and was similar to p levels by 8 hours. DBP increased the most within the first hour in the c and c+e treatment, decreased thereafter, and was similar to p levels by 8 hours. DBP levels remained below the 90 mm Hg level. HR was significantly increased by the c+e and e treatments, reached peak levels at 5 hours (75 b/min) and was similar to placebo levels by 24 hours. Caffeine and ephedrine plasma levels peaked between 2 and 4 hours and by 48 hours they returned to placebo levels. It was concluded that in normo-tensive healthy young individuals acute ingestion of a preparation of caffeine, ephedrine or the two in combination would not have long lasting adverse effects on blood pressure or heart rate.