Multiple sleep latency tests during the constant routine

Sleep. 1992 Oct;15(5):396-9. doi: 10.1093/sleep/15.5.396.


The "post-lunch dip" is a common behavioral phenomenon, though perhaps a misnomer. Biphasic models of the human sleep tendency rhythm suggest an alternative explanation for the afternoon decline in alertness. Sleep tendency was measured with the Multiple Sleep Latency Test (MSLT) at 2-hour intervals in 16 volunteers from three age groups (ages 10-12, ages 16-17, ages 62-74 years) during a constant routine in which small meals were given each hour. Baseline scores showed no significant Time of Day effect, although a trend for an afternoon dip was present in the eldest group. During the constant routine, a significant Time of Day effect was found for the two older groups and not for the prepubertal group. The results indicate a midday increase in sleep tendency that is unrelated to food intake but that may be related to developmental or maturational processes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Aged
  • Aging / physiology*
  • Arousal / physiology*
  • Cerebral Cortex / physiology
  • Child
  • Circadian Rhythm / physiology*
  • Eating / physiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Polysomnography*
  • Reaction Time / physiology*
  • Sleep Stages / physiology*