Case-control study, 2026
How does the menstrual cycle affect sleep?
Women with ovulatory cycles sleep longer and have longer REM sleep than those without ovulation, but the five phases of the cycle do not show significant differences in sleep. Whether you ovulate appears to matter more than which cycle phase you are in.
What they did
Study of 130 women aged 20-35. Ovulation was detected using LH urine tests. Sleep data were collected using Fitbit Alta HR trackers, which measured total sleep time and sleep stage duration (REM, light, and deep sleep). Sleep was analyzed separately for each of the five menstrual cycle phases.
What they found
Women with ovulatory cycles slept longer and had longer REM phases compared to women without ovulation. No significant differences in total sleep duration or sleep stage distribution were observed across the five menstrual cycle phases among women with detected ovulation.
What it means for you
The presence or absence of ovulation may affect your sleep duration and REM sleep, but being in different phases of your cycle does not appear to change sleep. The study used wearable sleep trackers rather than laboratory sleep monitoring, and included only young women.
130
women studied
5
menstrual cycle phases analyzed
26.2
average age in years
About the study
- Original title
- Women With Ovulatory Cycles Have Longer Sleep, but Phases of Their Menstrual Cycles Do Not Differ in Sleep Characteristics
- Authors
- Wachowicz A, Galbarczyk A, Marcinkowska UM et al.
- Journal
- American journal of human biology : the official journal of the Human Biology Council
- Year
- 2026
- Study design
- Case-control study
- Participants
- 130
- What was tested
- None
- Open access
- Yes
- Read the paper
- doi.org/10.1002/ajhb.70247
Original abstract
Objectives: Duration and quality of sleep are influenced by many factors, including hormonal changes. The aim of this study was to investigate the differences between the phases of the menstrual cycle in total sleep duration and sleep stage distribution, specifically the duration of rapid eye movement (REM) phase, light, and deep sleep states and compare sleep parameters between ovulatory and anovulatory cycles. Methods: The study involved 130 women aged 20-35 (mean = 26.2 years; SD = 4.14). Ovulation was detected using luteinizing hormone (LH) urine tests. Sleep data were collected using the Fitbit Alta HR trackers, which measured total sleep time and the duration of sleep stages. Sleep parameters were analyzed separately for each of the five phases: menstrual bleeding, follicular, periovulatory, luteal, and premenstrual using repeated measures ANOVA. Differences between ovulatory and anovulatory cycles were assessed using Student's t-test. Results: Women with the ovulatory cycle slept longer and had longer REM phases compared to women without ovulation. No statistically significant differences were observed in total sleep duration or sleep stage distribution across five phases of the menstrual cycle among women with detected ovulation. Conclusion: The findings suggest that ovulatory status might be associated with differences in total sleep time and REM sleep duration, whereas sleep duration and sleep stage distribution across menstrual cycle phases remain relatively constant. These results suggest that the presence of ovulation, rather than phase-specific changes during the cycle, may play a more important role in shaping sleep characteristics.
Reproduced under CC-BY.