Breakfast cereal and caffeinated coffee: effects on working memory, attention, mood, and cardiovascular function.Physiol Behav 1999; 67(1):9-17PB
This study examined the effects of breakfast cereal and caffeinated coffee on working memory, attention, mood, and cardiovascular function. One hundred and forty-four volunteers (72 male, 72 female, mean age 21 years) were assigned to one of the groups formed by combining breakfast (cereal versus no breakfast) and caffeine (caffeinated versus decaffeinated coffee) conditions. The volunteers completed a baseline session between 0800 and 0845 h. The breakfast/caffeine administration took place between 0845 and 0915 h. They then completed another test session (starting at 0945) and had a coffee break at 1045, followed by a final session starting at 1145. The results showed that those who consumed breakfast cereal had a more positive mood at the start of the test sessions, performed better on a spatial memory task, and felt calmer at the end of the test session than those in the no breakfast condition. Ingestion of caffeine had no effect on initial mood or working memory, but it did improve encoding of new information and counteracted the fatigue that developed over the test session. Caffeine increased blood pressure and pulse rate, whereas breakfast cereal consumption only had an effect on pulse. Overall, these results confirm previous findings on the effects of breakfast and caffeine, and demonstrate distinct profiles for two common examples of early-morning food and drink, breakfast cereal and caffeinated coffee.