Related Experiment Video
Updated: Jul 6, 2026
Multi-Modal Home Sleep Monitoring in Older Adults
Published on: January 26, 2019
Exploratory analysis of cerebral oxygen reserves during sleep onset in older and younger adults
Barbara W Carlson1, Virginia J Neelon, John R Carlson
1School of Nursing, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. bcarlson@email.unc.edu
Objectives:
To explore differences in cerebral oxygen reserves during sleep in old and young adults.
Design:
Descriptive cross-sectional study.
Setting:
General clinical research center.
Participants:
Nine old (aged 65-84) and 10 young (aged 21-39) adults.
Measurements:
Subjects were monitored during the first nightly sleep cycle using standard polysomnography, including measures of arterial oxyhemoglobin saturation (SaO(2)). Changes in regional cerebral oxyhemoglobin saturation (rcSO(2)) were used to estimate cerebral oxygen reserves. General linear models were used to test group differences in the change in SaO(2) and rcSO(2) during sleep.
Results:
Older subjects had lower SaO(2) than young subjects before sleep (baseline) (F((1,18))=5.1, P=.04) and during sleep (F((1,18))=10.7, P=.01). During sleep, half of the older subjects and none of the younger ones had SaO(2) values below 95%. In addition, the older subjects had more periods of oxygen desaturation (drops in SaO(2) > or = 4%) (chi-square=24.3, P=.01) and lower SaO(2) levels during desaturation (F((1,18))=11.1, P<.01). Although baseline values were similar, rcSO(2) decreased during sleep 2.1% in older subjects (F((1,8))=3.8, P=.05) but increased 2.1% during sleep in younger subjects (F((1,9))=4.6, P=.04). When the older subjects awakened from sleep, rcSO(2), but not SaO(2), returned to baseline; both returned to baseline in younger subjects.
Conclusion:
This exploratory analysis generated the hypothesis that lower SaO(2), combined with declines in regional blood flow, contributes to decline in cerebral oxygen reserves during sleep in older subjects. Further study will assess the effects of factors (e.g., medical conditions, subclinical disorders, and sleep architecture) that might account for these differences.
