New research from Eight Sleep Labs
Eight Sleep Labs today announces findings from a new study now available as a preprint, investigating how menopause and aging affect core body temperature rhythms during sleep, and whether restoring those rhythms via the Pod, could improve overnight cardiovascular recovery and sleep. The research reveals that aging, independent of menopausal status, disrupts the circadian rhythm of core body temperature, but that the temperature regulation capabilities of the Pod can restore that rhythm while improving cardiovascular recovery.
Previous research has shown a close link between the circadian rhythm of core body temperature and sleep quality. Under healthy conditions, core body temperature follows a characteristic U-shaped pattern overnight: it declines before sleep onset to support sleep initiation and early-night deep sleep, then gradually rises toward morning supporting REM sleep. In this study, we examined whether this overnight temperature rhythm is altered by aging or menopause, and whether the Pod can enhance this rhythm.
To address this question, we studied 30 postmenopausal women taking hormone replacement therapy (HRT), 30 postmenopausal women not taking HRT, and 30 age-matched men. All participants slept for one week with Pod temperature regulation OFF and one week with Pod temperature regulation ON. During each week, participants ingested a core temperature capsule that continuously recorded internal body temperature throughout a 24-hour period, enabling precise measurement of circadian temperature patterns throughout sleep and waking hours.
Key takeaways
When the Pod’s temperature regulation was OFF, participants showed nearly flat core body temperature patterns throughout sleep, rather than the characteristic U-shaped curve observed in younger adults. This flattened pattern appeared in both postmenopausal women and age-matched men, indicating aging rather than menopause drives circadian rhythm temperature disruption.
However, when the Pod’s temperature regulation was ON, the healthy U-shaped curve in core body temperature was restored across participant groups. This U-shaped curve is important not only for sleep quality but also for metabolic flexibility and cognitive health.
Additionally, with Pod temperatures ON, heart rate decreased by 3% and heart rate variability increased by 11%, compared to Pod OFF. Lower HR and higher HRV during sleep indicate improved cardiovascular recovery and reduced physiological stress, which is key for aging populations where cardiovascular disease becomes more prevalent.
These results suggest that restoring circadian core body temperature rhythms via the Pod’s overnight temperature regulation may be a key mechanism to improve nighttime recovery in postmenopausal women and older adults.
Figure: Restoring the body’s natural temperature rhythm and lowering heart rate during sleep. Average core body temperature (top) and heart rate (bottom) across 24 hours with the Pod ON (blue) versus OFF (gray). Time is shown as hours since falling asleep, and the gray-shaded regions indicate the average sleep window. With the Pod ON, core body temperature shows a deeper U-shape curve, whereas with Pod OFF the line is flat. For heart rate, we see the Pod further reduces sleeping heart rate during sleep. Lines represent study group means.
New and noteworthy
To our knowledge, this is the first study to:
- Examine the circadian rhythm of core body temperature in postmenopausal women and how it relates to overnight cardiovascular recovery and sleep quality.
- Show that age, rather than menopause itself, is what likely diminishes circadian rhythm.
- Demonstrate that the Pod by Eight Sleep can restore this circadian rhythm in older adults, thus significantly improving cardiovascular recovery during sleep.
Together, these findings show that the Pod restores age-related disruptions in circadian core body temperature during sleep, which is key for sleep quality, metabolic flexibility, and cognitive function. Overall, the Pod is a fantastic non-pharmacological strategy to restore core body temperature rhythmicity and improve cardiovascular recovery during sleep in older adults, including postmenopausal women.
To read the full scientific paper, see our preprint.
