MEAL COMPOSITION AND ITS EFFECT ON POSTPRANDIAL SLEEPINESS

Drowsiness is a commonly experienced phenomenon following food ingesti on. The present two experiments were designed to assess separately the effects of a solid meal compared to a liquid meal and to an equal vol ume of water, and the effects of meal constituents (high-fat, high-car bohydrate, or mixed meal) on objective postprandial sleep latencies. T en normal male subjects participated in each study. Both studies used identical protocols, differing only in the meals the subjects were fed . All subjects underwent a pre-meal baseline nap at 1600 hours. At 170 0 hours, subjects consumed a test meal. Naps followed at 1730, 1800, 1 900, and 2000 hours. Sleep onset latency was determined by standard po lysomnographic measures. In both studies, a one-way repeated-measures ANOVA procedure revealed no significant difference in sleep latencies among the meal conditions for the nap at 1600 hours. However, for the postprandial naps at 1730, 1800, and 2000 hours, the solid meal demons trated a significant decrease in postprandial sleep latency compared w ith an equivalent volume of water (control). No significant difference s in sleep latency were found between the food constituents. Results i ndicate that in contrast to a liquid meal, a solid meal produces a dec rease in sleep onset latency when compared to an equivalent Volume of water. Further, it was demonstrated that meal constituents have no eff ect on postprandial sleepiness. (C) 1997 Elsevier Science Inc.