Journal article
Absence of Seasonal Variation in the Phase of the Endogenous Circadian Rhythm in Humans
Chronobiology international, Vol.15(6), pp.623-632
1998
Handle:
https://hdl.handle.net/2376/114699
PMID: 9844750
Abstract
Humans may be subject to seasonal variations, as evidenced by the existence of seasonal affective disorder (SAD) and midwinter insomnia. However, some recent studies have shown that the seasonal variation in the phase of the circadian rhythm is relatively weak in healthy humans. In the present study, evidence is found that there is no seasonal variation in the phase of the endogenous circadian rhythm at all. Body temperature, cortisol excretion, and subjective alertness of six subjects recorded under constant routine conditions showed no systematic seasonal variation in circadian phases. This finding indicates that secondary zeitgebers blocked or counterbalanced the seasonal variation in the entrainment effect of the natural photo-period. The human being may live in an environment in which the photoperiod has lost its status of primary zeitgeber. (Chronobiology International, 15(6), 623-632, 1998)
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Details
- Title
- Absence of Seasonal Variation in the Phase of the Endogenous Circadian Rhythm in Humans
- Creators
- Hans P. A Van Dongen - 1Unit for Experimental Psychiatry, University of PennsylvaniaGerard A Kerkhof - 2Department of Physiology, Leiden University, The NetherlandsJohn H. M Souverijn - 3CKCL Department, Leiden University Medical Center, The Netherlands
- Publication Details
- Chronobiology international, Vol.15(6), pp.623-632
- Academic Unit
- Medical Education and Clinical Science, Department of
- Publisher
- Informa UK Ltd
- Identifiers
- 99900547508101842
- Language
- English
- Resource Type
- Journal article