TY - JOUR
T1 - The cortisol awakening response and autonomic nervous system activity during nocturnal and early morning periods
AU - Izawa, Shuhei
AU - Sugaya, Nagisa
AU - Yamamoto, Ryuichiro
AU - Ogawa, Namiko
AU - Nomura, Shinobu
PY - 2010
Y1 - 2010
N2 - The current study focuses on autonomic nervous system activity during sleep as a physiological aspect of sleep quality, and investigated the associations between the cortisol awakening response (CAR) and autonomic activity during sleep and after awakening. Ambulatory electrocardiograms were obtained from 20 participants, who also provided saliva samples (at the time of awakening, and 30, 45, and 60 min after awakening) and rated the subjective quality of their sleep at home. Autonomic activity was assessed with the Lorenz plot indices, cardiac sympathetic index (CSI) and cardiac vagal index. Total salivary cortisol secretion after awakening was calculated as area under the curve with respect to ground (AUCG) and increase (AUCI). After controlling for confounding factors, including sleep duration and awakening time, cortisol AUCG and AUCI were both found to be negatively correlated with CSI during the 30 min before and after awakening: before (r = -0.526 and -0.601 respectively) and after (r = -0.540 and -0.493 respectively). Self-reported sleep quality was not associated with the CAR. These results suggest that the CAR is negatively affected by basal sympathetic activity immediately before and after awakening, but not affected by subjective sleep quality. Physiological arousals around the time of awakening might inhibit the CAR.
AB - The current study focuses on autonomic nervous system activity during sleep as a physiological aspect of sleep quality, and investigated the associations between the cortisol awakening response (CAR) and autonomic activity during sleep and after awakening. Ambulatory electrocardiograms were obtained from 20 participants, who also provided saliva samples (at the time of awakening, and 30, 45, and 60 min after awakening) and rated the subjective quality of their sleep at home. Autonomic activity was assessed with the Lorenz plot indices, cardiac sympathetic index (CSI) and cardiac vagal index. Total salivary cortisol secretion after awakening was calculated as area under the curve with respect to ground (AUCG) and increase (AUCI). After controlling for confounding factors, including sleep duration and awakening time, cortisol AUCG and AUCI were both found to be negatively correlated with CSI during the 30 min before and after awakening: before (r = -0.526 and -0.601 respectively) and after (r = -0.540 and -0.493 respectively). Self-reported sleep quality was not associated with the CAR. These results suggest that the CAR is negatively affected by basal sympathetic activity immediately before and after awakening, but not affected by subjective sleep quality. Physiological arousals around the time of awakening might inhibit the CAR.
KW - Ambulatory electrocardiograms
KW - Autonomic nervous system activity
KW - Awakening
KW - Cortisol
KW - Sleep quality
UR - http://www.scopus.com/inward/record.url?scp=79851504679&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79851504679&partnerID=8YFLogxK
M3 - Article
C2 - 21178943
AN - SCOPUS:79851504679
SN - 0172-780X
VL - 31
SP - 685
EP - 689
JO - Neuroendocrinology Letters
JF - Neuroendocrinology Letters
IS - 5
ER -