ABSTRACT
Exercise has widely been shown to improve cognition, potentially by making individuals more receptive to sensory stimulation or inhibiting irrelevant information. Caffeine, one of the world’s most widely used stimulants, seems to have similar effects. It seems that both exercise and caffeine improve cognitive function separately, but little research has been done examining their combined effects. The purpose of this study was to examine the impact of caffeine and exercise, independently and combined, on cognitive function. 20 healthy college students completed the study. These participants were low caffeine consumers. Each participant came to the lab 5 times. During the first session, they completed a graded exercise test on a cycle ergometer to determine ventilatory threshold (VT). The following four sessions were test sessions involving supplementation and exercise. During these, each participant engaged in 30 minutes of cycling (at 90% VT) or 30 minutes of quiet reading after consuming either caffeine (at 4 mg/kg body weight) or a placebo. The Contingent Continuous Performance Task (CPT) and Wisconsin Card Sorting Task were used to measure cognitive function and were completed 5 minutes and 20 minutes after exercise or quiet reading. There were no significant differences found for any variables tested, for condition effect, time effect or condition*time interaction, except for a significant time effect on false alarms on the Contingent CPT (p = 0.017). This study may have been limited by multiple variables including the population, executive function measures, caffeine dosage, or exercise prescription. These findings point to the need for future research to understand the changes in cognition from exercise and caffeine in combination. Future research may include looking at exercise at different intensities, different dosages of caffeine, or looking at the long-term cognitive effects.