Menopause status is associated with circadian- and sleep-related alterations.
The aim of the study was to investigate whether postmenopausal women show differences in circadian-related variables and sleep characteristics compared with premenopausal women, and to analyze potential associations between these circadian-related variables and abdominal fat distribution or metabolic syndrome (MetS) components.



A total of 177 women were studied (127 premenopausal, 50 postmenopausal). Sixty percent of the total population was overweight/obese, with no significant differences between premenopausal (60%) and postmenopausal women (62%) (P = 0.865). Wrist temperature (WT) and rest-activity cycles were measured during 8 consecutive days, and sleep and food diaries collected. MetS characteristics and daily patterns of saliva cortisol were analyzed. Sleep characteristics were assessed with domiciliary polysomnography.



Postmenopausal women showed a less robust rhythm in WT with lower amplitude (°C) (0.8 ± 0.4 vs 0.9 ± 0.5) (P < 0.05) and lower mean temperature values at the midpoint of sleep than premenopausal women. Postmenopausal women were also more morning-type than premenopausal women, showing a phase advance of approximately 1 hour in WT and rest-activity rhythms, and more morning-type habits (earlier sleep onset/offset and breakfast intake) (P < 0.05). Postmenopausal women showed higher levels of activity in the morning and lower in the evening compared with premenopausal women (P < 0.05). Daily variability in cortisol was significantly reduced in postmenopausal women compared with premenopausal women (P < 0.05). Postmenopausal women had increased frequency of sleep-related breathing abnormalities (P < 0.0001). In the women studied, abdominal fat and MetS were associated with an increase in circadian alterations (high fragmentation and low amplitude of the rhythm) (P < 0.05).



Postmenopausal women exhibit loss of circadian robustness and an increase in sleep abnormalities compared with premenopausal women.
1Department of Physiology, Faculty of Biology, University of Murcia, Murcia, Spain 2Universidad Autónoma de Chile, Santiago de Chile, Chile 3IMIB-Arrixaca, Murcia, Spain 4Neumology Service of Hospital Virgen de Arrixaca, Murcia, Spain 5Instrumentation Service Psychological, University of Murcia, Murcia, Spain.
Cecilia
C
Gómez-Santos
Cristina Bandín
CB
Saura
J A Ros
JA
Lucas
Pedro
P
Castell
Juan A
JA
Madrid
Marta
M
Garaulet
D050153:Abdominal Fat; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D002940:Circadian Rhythm / Q000502:physiology*; D004032:Diet; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D024821:Metabolic Syndrome / Q000175:diagnosis / Q000503:physiopathology; D008875:Middle Aged; D009765:Obesity / Q000175:diagnosis / Q000503:physiopathology; D056128:Obesity, Abdominal / Q000453:epidemiology; D050177:Overweight / Q000503:physiopathology; D017698:Postmenopause / Q000502:physiology*; D017697:Premenopause / Q000502:physiology*; D012463:Saliva / Q000737:chemistry; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000453:epidemiology; D013030:Spain / Q000453:epidemiology
D001786:Blood Glucose; D006854:Hydrocortisone