ENHANCEMENT OF ARITHMETIC SKILLS BY COFFEE-DRINKING : DOUBLE-BLIND STUDY FOR CAFFEINE-CONTAINING AND CAFFEINE-FREE COFFEES

Effects of caffeine on arithmetic performance were investigated with 99 university students. A double-blind study for arithmetic skill test was carried out, after drinking caffeine-free or caffeine-containing (180 mg) coffee. Eight rounds for the arithmetic tests were performed ; four rounds before, and four rounds after coffee break. Each round was 1-min arithmetic tests three times with 1-min intervals. The arithmetic skill and the ratio of arithmetic errors per each round were averaged. Simultaneously, heart rate was also measured. The mean values of arithmetic skill and the ratio of errors at the 4th round (n=99) were 81.4±1.7/min and 0.28±0.02%. The heart rate was 76.9±1.5 beats/min. Before and after coffee-drinking, arithmetic skill was enhanced, whereas the heart rate was significantly decreased. As compared with the caffeine-free group, caffeine significantly enhanced the arithmetic skill 45 and 60 min after coffee-drinking. But the ratio of arithmetic errors was not affected. The heart rate was significantly decreased only at 45 min later. These results indicate that caffeine (-containing coffee drinking) can enhance arithmetic skill and decrease the heart rate, presumably resulting from stimulation of the central nervous system.