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Inducing a 6‐hour phase advance in the elderly: effects on sleep and temperature rhythms
Author(s) -
CARRIER JULIE,
MONK TIMOTHY,
BUYSSE DANIEL,
KUPFER DAVID
Publication year - 1996
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1046/j.1365-2869.1996.00015.x
Subject(s) - circadian rhythm , sleep (system call) , wakefulness , non rapid eye movement sleep , rhythm , psychology , slow wave sleep , phase (matter) , medicine , anesthesia , audiology , neuroscience , eye movement , chemistry , electroencephalography , organic chemistry , computer science , operating system
The aim of this experiment was to study the effects on sleep and temperature rhythms of a 6‐hour (h) phase advance of the sleep/wake cycle in healthy elderly subjects. Twenty‐five subjects (77–91 y.o.) lived in a time‐isolation apartment on an experimenter‐controlled routine for 15 days. The experiment started with five baseline days. The wake time on the 6th night was phase advanced by 6‐h and the routine for the remaining nine days was held constant to the new phase position. After the phase shift, temperature circadian rhythms showed rapid phase adjustment leading to a small (1.1 h) phase angle disturbance. Sleep efficiency decreased and showed little evidence of recovery back to baseline following the phase shift. The amount of wakefulness in the first two hours of sleep increased after the phase shift while no effect was found for the amount of wakefulness in the last two hours of sleep. The 6‐h phase shift did not change the percentages of REM and SWS. Early night sleep propensity appeared to be very sensitive to a small phase angle disturbance of the circadian oscillator in this healthy elderly sample. The phase angle disturbance induced in this study did not seem to be large enough to have a systematic effect on sleep propensity at the end of the night or on REM sleep parameters, suggesting that these variables are less sensitive to an altered phase relationship with the circadian oscillator than early night sleep propensity. These results indicate that there might be a variable phase tolerance for different sleep parameters in older subjects.