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Oxygen consumption, circadian rhythmicity and sleep

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Fraser, Geoffrey J(Geoffrey John) (1989) Oxygen consumption, circadian rhythmicity and sleep. Research Master thesis, University of Tasmania.

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Abstract

Oxygen consumption is lower during sleep than relaxed wakefulness. However,
there is disagreement as to the particular metabolic changes which produce the
difference. The present study assessed
(i) the contribution of sleep, circadian cycle and the specific dynamic action effect of
the evening meal, to the fall in metabolic rate during the sleep period.
(ii) the effects of sleep stage on oxygen consumption which had been suggested by
previous researchers, and
(iii) the effect of body movement arousals on oxygen consumption.
Five subjects were tested for a total of nine nights under three conditions in a repeated
measures design. Subjects were confined to bed throughout their usual sleep period,
but were allowed to go to sleep 0, 3 or 6 hours following their usual time for lights
out. Oxygen consumption was measured in all conditions for the half hour before
and after each of the times for lights out and then throughout the sleep period
following lights out. The results demonstrated that changes in energy expenditure
during the sleep period are a function of both sleep and circadian cycle. In this study
the contribution of the components was approximately equal. However, the effect of
sleep was rapid, with oxygen consumption values reaching an asymptote within
fifteeen minutes of sleep onset, while the effect of circadian cycle was constant over
the assessment period. No evidence was found implicating the specific dynamic
action effect of the evening meal in the reduction in sleep period metabolic rate. The
results of previous studies can be interpreted as being due to the combined effect of
circadian and sleep influences, and not to specific differences in metabolic rate
between separate sleep stages. These would appear to be artifactual. In addition, the
period of metabolic disturbance following a movement arousal was shown to be
longer than that suggested by previous researchers.

Item Type: Thesis (Research Master)
Keywords: Sleep, Circadian rhythms, Oxygen, Respiration
Copyright Holders: The Author
Copyright Information:

Copyright 1989 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Thesis (M.A.)--University of Tasmania, 1990. Bibliography: leaves 77-89

Date Deposited: 08 Dec 2014 23:59
Last Modified: 16 Aug 2016 06:13
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