A comparison of feeding to cephalic stimulation on postprandial sleepiness

This study investigated the effects of ingestion of a meal compared to a sham feeding on objectively measured sleepiness. It was hypothesized that the ingestion of a solid meal would produce significantly greater postprandial sleepiness evidenced by shorter sleep onset latencies (SOL) when compared to a sham feeding. Eleven men and eight women without evidence of gastrointestinal disease or sleep disorders participated in the 2-day study. Subjects underwent a premeal baseline nap at 1600 hours and were given a standardized meal at 1700 hours. On one study day, subjects consumed the entire meal, whereas on another study day, they were asked to chew and then expectorate the meal. Naps with polysomnographic monitoring followed at 1730, 1800, and 1900 hours. Sleep onset latencies were determined by standard polysomnographic measures. Statistical analyses revealed the sleep onset latencies for the two meal conditions differed significantly at the 1800 hours postprandial nap only. Individuals demonstrated a transient decrease in sleep latency after consuming a meal compared to a sham feeding. These results lend support to the existence of a gastrointestinal effect on postprandial sleepiness.