A Pilot Study of Some Physiological and Psychological Effects of Caffeine

Eleven volunteers participated in a study to characterize some physiological and psychological effects of caffeine in a double-blind, crossover study. During one week, the subjects were given a caffeine-containing beverage, and during a second week, they were given an identically appearing non-caffeine beverage. Data were accumulated based on urine tests and a medical examination. Diary entries revealed typical effects of caffeine such as increased energy, nervousness and restlessness which were observed after the week of caffeine consumption. A medical examination showed increased adrenal function for those subjects who were non-users or occasional users of caffeine beverages. Habitual users of caffeine beverages showed no obvious adrenal effects. Determination of pH, surface tension and viscosity of urine during the two weeks of the study showed evidence that caffeine is an "anabolic" agent according to a theory suggested by Dr. E. Revici.