Objective: This study aims to evaluate patterns in actigraphy-defined sleep measures across the menstrual cycle by testing the hypothesis that sleep would be more disrupted in the premenstrual period (ie, within the 14 d before menses).
Methods: A community-based longitudinal study of wrist actigraphy–derived sleep measures was conducted in 163 (58 African American, 78 white, and 27 Chinese) late-reproductive-age (mean [SD], 51.5 [2.0] y) women from the Study of Women’s Health Across the Nation Sleep Study. Daily measures of sleep (sleep efficiency [%] and total sleep time [minutes]) and movement during sleep (mean activity score [counts]) were characterized using wrist actigraphy across a menstrual cycle or 35 days, whichever was shorter. Data were standardized to 28 days to account for unequal cycle lengths and divided into four weekly segments for analyses.
Results: Sleep efficiency declined gradually across the menstrual cycle, but the decline became pronounced on the fourth week (the premenstrual period). Compared with the third week, sleep efficiency declined by 5% (P < 0.0001) and mean total sleep time was 25 minutes less (P = 0.0002) on the fourth week. We found no significant differences between the mean for the second week and the mean for the third week. The association of weekly segments with sleep efficiency or total sleep time was modified by sociodemographic and lifestyle factors, including body mass index, race, study site, financial strain, marital status, and smoking.
Conclusions: Among late-reproductive-age women, sleep varies systematically across the menstrual cycle, including a gradual decline in sleep efficiency across all weeks, with a more marked change premenstrually during the last week of the menstrual cycle. These sleep changes may be modified by altering lifestyle factors.
From the 1Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI; 2Departments of Psychiatry and Preventive Medicine, Rush University Medical Center, Chicago, IL; Departments of 3Epidemiology and 4Psychiatry, University of Pittsburgh, Pittsburgh, PA; and 5Division of Epidemiology, Department of Public Health Sciences, University of California at Davis, Davis, CA.
Received December 12, 2013; revised and accepted March 5, 2014.
Work was performed at the University of Michigan, Rush University MedicalCenter, University of California at Davis, and University of Pittsburgh.
Funding/support: This work on the Study of Women’s Health Across the Nation Sleep Study was supported by the National Institute on Aging (NIA; R01AG019360, R01AG019361, R01AG019362, and R01AG019363). The Study of Women’s Health Across the Nation received grant supportfrom the National Institutes of Health (NIH); the Department of Health andHuman Services, through the NIA; the National Institute of Nursing Research; and the NIH Office of Research on Women’s Health (U01NR004061, U01AG012505, U01AG012535, U01AG012531, U01AG012539, U01AG012546, U01AG012553, U01AG012554, and U01AG012495). Sleep data were processed with the support of grant RR024153. The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the NIA, National Institute of Nursing Research, Office of Research on Women’s Health, or NIH.
Financial disclosure/conflicts of interest: None of this work was supported by commercial sources. D.J.B. has served as a paid consultant for Merck, Pfizer, Purdue Pharma, Philips Respironics, and General Sleep Corp. Consulting fees for each company are less than US$10,000 annually. D.J.B. has been paid for continuing education lectures supported by Astellas and Servier, and for online educational presentations supported by CME Outfitters and Medscape. The remaining authors declare no conflicts of interest.
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Address correspondence to: Huiyong Zheng, PhD, Department of Epidemiology, University of Michigan School of Public Health, Room1854, 1415 Washington Heights, Ann Arbor, MI 48109. E-mail: email@example.com