Abstract
A COMMON approach to the understanding of human circadian rhythms is to study their modifiability. Attempts to replace the 24 h sleep–wakefulness rhythm in man by cycles of slightly altered length (for example, 21 or 27 h) have had some success1,2. Attempts to produce sleeping–waking rhythms which are a multiple of the natural cycle length such as 12 or 48 h have not, however, been very successful2,3; the reasons for this are not yet clear.
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References
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Kleitman, N., Sleep and Wakefulness, 175 (Univ. Chicago Press, 1963).
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MEDDIS, R. Human Circadian Rhythms and the 48 Hour Day. Nature 218, 964–965 (1968). https://doi.org/10.1038/218964a0
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DOI: https://doi.org/10.1038/218964a0
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