ABSTRACT
ABSTRACT. Low blood sugar level resulting from fasting has been shown to reduce performance on a number of cognitive tasks. In this study, 80 nondiabetic A-level students missed breakfast. They completed a version of Daneman and Carpenter's Listening Span Test at 9.00 A.M. Half were then given a drink containing glucose, while the other half received a saccharine drink matched for taste. After 20 minutes, both groups completed another form of the Listening Span Test. A subset of the sample had their blood glucose levels determined immediately before the drink and again before the second application of the test. Blood glucose levels did not change, but listening span performance significantly improved after a glucose drink, yet not after a saccharine drink. It is concluded that missing breakfast does not seriously affect blood sugar levels in healthy young students, but listening span performance, which is a good predictor of listening comprehension, is improved when fasting individuals imbibe a glucose-rich drink, although not when a saccharine drink is drunk. Ideally students should eat breakfast, but if this is omitted, then a glucose snack or drink before the first class may reverse any adverse effects.
