The purpose of the present research was to study the effect of caffeine consumption on arousal, activation, and dart-throwing performance at different times of day. Based on previous works “arousal” has been defined as the energetic state at any particular time and task-related “activation” as the task-related change in state from resting baseline to the task situation. 24 participants (mean and standard deviation of 21.86 ± 2.20 years of age) participated in a randomized double-blind placebo-controlled repeated-measures crossover study and were studied for 6 weeks and 1 session per week in order to measuring arousal, activation, and dart-throwing performance in the morning and evening. In this study, an increase in skin conductance level (SCL) was used as the marker of arousal increase. The results of repeated measures analysis of variance indicated that caffeine and placebo ingestion lead to increased arousal and activation but it does not affect dart-throwing performance. Further, time of day did not affect the results.
