Effects of evening meals and caffeine on cognitive performance, mood and cardiovascular functioning.

An experiment was carried out to examine the effects of an evening meal and caffeine (3 mg/kg) on performance, mood and cardiovascular functioning. Subjects given a meal reported that they felt stronger, more proficient and more interested than subjects in the no-meal condition. They also performed a logical reasoning task more quickly than the no-meal group. However, no effects were found on sustained attention tasks or tasks involving recall or recognition of word lists. The effects of evening meals are, therefore, different from either those observed after lunch or breakfast. Caffeine improved alertness and performance on sustained attention tasks for the group as a whole. Interactions between caffeine conditions and levels of impulsivity of the subjects were also found in memory tasks.