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Updated: Jul 25, 2026

Quantifying Infra-slow Dynamics of Spectral Power and Heart Rate in Sleeping Mice
Published on: August 2, 2017
Age differences in sleep-wake behavior under natural conditions
C J Kramer1, G A Kerkhof, W F Hofman
1Department of Psychonomics, University of Amsterdam, Netherlands.
Abstract:
Differences in lifestyle may account for a considerable portion of the reported age-related changes in overt circadian rhythmicity. By instructing a group of healthy, noninstitutionalized, elderly subjects and a group of young adults to keep a sleep-wake log for a period of two weeks, and to wear an activity monitor for an overlapping period of 11 days, we attempted to assess age-related differences in the habitual sleep-wake behavior, in particular its day-to-day variability. Four clusters of coherent variables were constructed, reflecting (1) circadian phase, (2) variability of sleep-wake behavior, (3) sleep-wake continuity and (4) subjective sleep-wake quality. The results showed that, in comparison with the young subjects, the elderly had a relatively advanced and more regular sleep-wake pattern, reported more midnight awakening and did not differ in their subjective sleep evaluation. In spite of a greater regularity in their lifestyle (which would favor a larger amplitude of the overt circadian rhythmicity) oral temperature measurements showed some evidence of a weakened 24-h periodicity in the elderly.
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