Sleep habits in Nigerian undergraduates

Background - Quantity of night sleep is shorter than 8 h in several developed countries, but similar data is not available for most African countries. The objective of this study was to describe the quantity of night sleep, factors that are associated with non-restorative sleep, and sleep habits in a population of undergraduates in Nigeria. Methods - Questionnaires were used to collect information about bedtimes, waketimes, intra-night awakenings, non-restorative sleep, and afternoon naps over a period of 14 days. Results - Mean duration of night sleep was 6.2 h (median 6.0, range 4.5-9.3), while mean duration of daytime naps was 70 min (median 75, range 10-315). Duration of night sleep was associated with day of the week and gender, but not with BMI. Non-restorative sleep, which occurred 25% of total sleep times, was associated with night sleep < 5 h, hypnotic use, alarm to wake, heavy workload, and afternoon naps. Intra-night sleep awakening occurred 58.5% of total sleep times. Afternon naps were taken by 225 (82%) of subjects. Conclusion - Duration of night sleep in this African population is not longer than the duration in Western countries. Intra-night awakening and non-restorative sleep; however, occur more frequently, and afternoon nap is usually in excess of 1 h.