Researchers at Harvard University published a study that analyzed more than 94,000 nights of Apple Watch sleep data to better understand how sleep patterns change during perimenopause. Here are the details:
Study analyzed over 94,000 nights of sleep data from Apple Watch
For the past few years, Apple has used the Apple Watch as a way to support large-scale health research through the Apple Research app.
This includes the Apple Women’s Health Study, Apple Heart and Movement Study, and Apple Hearing Study, which were launched in 2019 in collaboration with research partners including Harvard University, Brigham and Women’s Hospital, the American Heart Association, and the University of Michigan.
In February 2025, Apple announced that those studies have since grown to more than 350,000 participants across the United States.
Recently, the Harvard T.H. Chan School of Public Health published the results of a study (via Aaron Peris) that investigated how sleep patterns change during perimenopause.
The study used more than 94,000 nights of Apple Watch sleep data from 338 Apple Women’s Health Study participants between the ages of 25 and 59, the majority between 45 and 59.
According to the data, “in the 12 months before and after their last recorded menstrual period, many participants spent more time awake at night.”
The study also found that “in the 18 months leading up to menopause, 60% of women with sleep tracking experienced an increase in WASO (awakenings after sleep onset) compared to the previous 6 months,” with an average increase of 7%.
The researchers also noted that “in the 12 months before and after their last recorded menstrual period, participants slept approximately 0.8% more awake time after menopause than before.”
Importantly, the researchers emphasized that results varied widely between participants, noting that “everyone experiences perimenopause and menopause differently.”
Some participants experienced a significant increase in awake time after menopause, while others had no meaningful sleep changes at all.
Finally, participants in the study who tracked their sleep also recorded other menopausal symptoms, including 82.3% of hot flashes, 68.1% of irritability, 65.7% of mental fatigue, and 65.6% of sexual symptoms.
For participants who reported more severe menopausal symptoms, the symptoms most closely associated with worse sleep were bladder symptoms, joint symptoms, heart discomfort, and depressive symptoms.
The researchers also shared the following recommendations to help women achieve better sleep during perimenopause:
- Keep your sleep environment cool
- maintain a consistent sleep schedule
- adopt regular movements
- Avoid common bladder irritants and limit fluid intake in the hours before bedtime
- Prioritize relaxation and mindfulness techniques in your pre-bedtime routine.
Click this link for more information on the study results.
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