For women, good quality sleep is tightly linked to your body temperature staying within an optimal range throughout the night. But here’s the twist: hormones like estrogen and progesterone shift a lot during different life stages—birth control, pregnancy, and menopause. And when hormones change, so does how your body handles heat.
That’s why at Eight Sleep, we decided to study how women using the Pod adjust their sleep temperatures across life’s major stages. The results? A 5°F swing between the coolest and warmest groups. That difference can mean the line between tossing and turning—or deep, restorative sleep.
Key Takeaways
- Pregnancy and Menopause: Women in both life stages set their Pods at the coldest settings of all the groups we analyzed. This means they are looking to cool down during sleep.
- HRT Effect: Women doing hormone replacement therapy (HRT) go for slightly warmer bedtime temperatures, looking to warm up when they first get in bed.
- Birth Control Impact: Women using hormonal birth control set warmer temperatures on the Pod for the first half of the night.
We surveyed 1,884 women sleeping on the Pod and studied their Pod temperatures. These women shared details about their menstrual cycle status and whether or not they were taking hormones for birth control or menopause. From there, we split the women into 6 groups:
- Regularly cycling with hormonal birth control (n=184)
- Regularly cycling without hormonal birth control (n=744)
- No cycle due to using hormonal birth control (n=250)
- Pregnant during their 3rd trimester on the Pod (n=39)
- Menopausal with HRT (n=255)
- Menopausal without HRT (n=412)
Then, we compared their Pod temperature settings across three phases of the night: Bedtime, Night (first 4 hours of sleep), and Dawn (+4 hours until waking).
The results are clear: women need different Pod temperatures during sleep based on their current life stage
3rd trimester pregnancy and menopausal women need the coolest Pod temperatures
The coldest Pod temperatures across the night were used by women who were in their 3rd trimester of pregnancy and menopausal women not taking HRT. In fact, across the entire night, these women use Pod temperatures significantly cooler (-2 to 5°F on average) than pre-menopausal women, regardless of whether they are using hormonal birth control.
- Pregnancy cranks up metabolism, which explains why women often prefer rooms up to 7°F colder in late pregnancy (ref). This explains why their Pod temperatures are so cold!
- Similarly, going through menopause without HRT is linked to heat-related discomfort and more hot flashes, making cooler Pod settings a go-to.
Women on hormonal birth control need the warmest Pod temperatures
At the other end, regularly cycling women using hormonal birth control set the warmest Pod temperatures: 4-5°F hotter on average than pregnant women in their 3rd trimester.
Even compared to women with regular cycles but not using hormonal birth control, those on birth control used slightly warmer Pod temperatures (by ~1°F on average), especially during the first half of the night.
Using birth control or HRT modifies the Pod temperatures women need
- Menopause with vs. without HRT: Women on HRT started the night with Bedtime Pod settings about 1.5°F warmer than those not using HRT. This finding lines up with research showing that taking combination estrogen and progesterone HRT leads to higher core body temperature compared to women not on HRT (ref).
- Regular cycle with vs. without birth control: Hormonal birth control use led to ~1°F warmer temperatures in the first half of the night. This finding aligns with research showing that women using hormonal birth control have warmer body temperatures throughout the menstrual cycle, even during the placebo pill phase (ref).
- No cycle due to using birth control (e.g. progesterone-only): Their settings landed in between regularly cycling women and menopausal women (see Figure).
Figure. Pod temperatures (in degrees Farenheit) that each group of women used, colored by menstrual cycle status. We show Pod temperatures for 3 different Phases, which are selected in the Eight Sleep app by the member: Bedtime (falling asleep), Night (first 4 hours of sleep), and Dawn (4+ hours of sleep until waking). Boxplots show the median (middle line), 25th & 75th percentiles (lower and upper bounds of the box), and the white dots represent the group means for each Phase.
Why It Matters
Scientific research directly comparing temperature regulation during sleep across these groups is limited. Our findings provide rare insight into how women’s sleep physiology interacts with hormonal transitions – from the high metabolic load of pregnancy, to the vasomotor instability of menopause, to the temperature-raising effects of birth control.
By personalizing sleeping temperatures across Bedtime, Night, and Dawn, the Pod helps women at every stage align overnight comfort with their unique physiology, supporting better sleep through life’s biggest transitions.
Appendix
A survey was sent out to all female Eight Sleep members to ask them about their current and past menstrual cycle status. 1,884 women voluntarily shared their current life stage, including past menstrual cycle dates (if correctly recalled or logged) and pregnancies while sleeping on the Pod. For each life stage, we pulled the previous 3 months of data that corresponded with that time period. We also ensured that there were no major changes in medications that might affect temperature regulation or sleep during that 3 month period. For pregnant women, we used week 28 through delivery. For pre-menopausal women, we pulled the three months of Pod temperatures where they reported being on birth control or not on birth control, with regular or no cycle for that period of time. We also excluded any women who had changed their birth control or cycle status within 3 months of the start date of their study time period. Lastly, for menopausal women, we pulled 3 months of data where they had not switched their potential HRT type or dosing, or their menopausal status for 6 consecutive months (i.e. no changes in the 3 months leading up to the start period of data we pulled).
For each person, we took their mean Bedtime, Night, and Dawn Phase temperatures across the 3 month period. These aggregated data were then used to compare Pod temperatures between groups at each of the 3 Phases (Bedtime, Night, and Dawn) with a mixed-model ANOVA. An alpha level of <0.05 defined significance. There was a significant main effect of cycle status (P<0.01), and a significant interaction effect between cycle status and Pod temperature Phase (P<0.01). We explored differences between cycle status groups (independent of temperature Phase) using independent t-tests with Bonferroni correction, and differences between cycle status groups depending on temperature Phase using dependent t-tests with Bonferroni correction. All differences reported above are significant (P<0.05) after the Bonferroni correction.
Note that although we did not directly measure core and skin temperatures in this study, the differences in Pod temperature preferences likely result from body temperature changes during each life stage as a result of fluctuating estrogen and progesterone. Importantly, these data show how women leverage the Pod’s dynamic temperature control to adapt and continue to sleep well throughout these hormonal transitions.
