Abstract Amphetamine, caffeine, and high ambient temperature (125.6 F) were compared with placebo to determine their effects on a variety of strength, psychomotor, and mental performance tasks and certain physiological measures of 24 young men who were students at the University of North Carolina. Performance was measured objectively only after each subject had been given standard extensive practice and acclimatization. The study permitted the conclusions that (a) 15 mg. of d-amphetamine sulfate significantly improved performance but caused a significant increase in heart rate, (b) 500 mg. of citrated caffeine did not produce a significant change in either the performance tasks or the physiological parameters measured, and (c) high ambient temperature (125.6 F) produced a significant improvement in performance.
Lovingood et al. (Wed,) studied this question.