Article Title



E. Surratt, A. Nordling, D. Han, W.M. Silvers

Whitworth University, Spokane, WA

Caffeine is a common stimulant with a relatively quick time of onset. Many researchers have studied the physiological responses individuals undergo after caffeine consumption, which may be influenced by tolerance or genetics. Reaction time (RT) tests have been previously utilized in caffeine studies, and provide an effective measurement of cognitive ability. However, many previous researchers reported findings within a clinical context and gave less attention to the effects of caffeine in a “real world” setting. This may be important, as some researchers suggest physiological effects from caffeine may be more situationally-dependent. PURPOSE: The purpose of this study was to understand the effects of “real world” caffeine consumption on RT in undergraduate students. METHODS: Nineteen college-aged students, ranging from ages 18-25 y, completed two simple RT tests, with and without caffeine. Participants signed up for two experimental sessions, 48 hr apart, which lasted approximately 45 min. Caffeine administration consisted of one 8 fl oz flavored drink (C), which contained 125 mg of caffeine. For the control session, participants consumed one 8 fl oz placebo (P) flavored drink in a similar fashion as to not distinguish from the caffeinated drink. After the participants sat for 30 min, they performed a simple RT test on a laptop. Participants wore noise-cancelling headphones when necessary. The tests consisted of clicking the mouse pad as quickly as possible once a circle on the screen changed from yellow to red. The average RT after five repetitions was recorded. Wilcoxon signed-rank test (significance level p ≤ 0.05) was used to determine the existence of significant differences between experimental conditions. RESULTS: No statistical difference (p = 0.687) was observed for RT between caffeine (M = 0.35, range = 0.421) and the placebo (M = 0.344, range = 0.266). CONCLUSION: Under these research conditions, caffeine did not improve RT. The primary explanation for the observed results was that the dose of caffeine administered (125 mg) may not have been large enough to elicit a significant effect on RT. Further research is needed to investigate larger doses of caffeine ingestion with a larger sample size.

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