The Development of Sleep and Wakefulness Cycle in Early Infancy and Its Relationship to Feeding Habit

Abstract

The purpose of this study was to evaluate the relationship between sleep and wakefulness patterns to feeding habits in early infancy. The population consisted of 33 neurologically normal infants studied during their first 4 months of life. The number of 30-min epochs with sleep (sleep epoch) were counted in each 4-hr period in a day and evaluated over time. The effects of feeding on sleep and wakefulness were examined by analyzing the rates of sleep epoch after feeding in each time period. The rates of sleep epochs in each time period showed specific patterns each week. From 2 weeks of age, sleep epochs appeared most frequently in time periods 0: 00–4: 00 and 4: 00–8: 00 (p<0.01). These periods also had significantly high rates of sleep epochs after feeding by week 2. From week 6 both the number of sleep epochs and the rate of sleep epochs after feeding in time periods from 8:00 to 20:00 tended to decrease. These results suggest that the development of the circadian oscillation is set as a sleep epoch first during the time period of 0: 00 to 8: 00. In addition, feeding alone seemed to have no role as a time cue in the first 4 months of life. © 1991, Tohoku University Medical Press. All rights reserved.