Development of the 24-h Rest-Activity Pattern in Human Infants

Infant Behav Dev. 2006 Apr;29(2):143-52. doi: 10.1016/j.infbeh.2005.11.001. Epub 2005 Nov 28.


The development of the 24-h rest-activity pattern was investigated in human infants under naturalistic conditions as assessed by continuous actigraphy. Seven infants and their mothers were recorded for 4 (n=1), 6 (n=5) and 12 months (n=1) after birth. Periodogram analysis of rest-activity data was performed over consecutive 10-day intervals. A weak 24-h rest-activity pattern was already present in some infants during the newborn period. The magnitude of the 24-h component in individual periodograms increased across the first months following a saturating function. The time constants of fitted saturating exponential functions--reflecting the rate of development of the 24-h pattern--ranged from 49 to 110 days (n=6) indicating a large interindividual variability. Furthermore, intraindividual variation was observed; the magnitude of the 24-h rest-activity component showed fluctuations around the trend. Miniaturized actigraphs are ideal tools for long-term longitudinal monitoring of rest-activity behavior in infants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Child Development / physiology*
  • Circadian Rhythm / physiology*
  • Female
  • Humans
  • Infant
  • Male
  • Mothers
  • Motor Activity
  • Rest / physiology*