Better recovery starts with sleeping on the Pod. In our most recent study in menopausal women and men 45+, we found that core body temperature is lower when sleeping on the Pod, which leads to improved cardiovascular recovery.
Key Takeaways
- Findings show that the Pod reduces core body temperature by 0.2°C (0.4°F) on average during sleep.
- This lower core body temperature led to an average heart rate variability (HRV) increase of 14% and heart rate (HR) decrease of 4% during sleep.
- We also found that the lower the core temperature, the stronger the cardiovascular benefits (increased HRV and decreased HR), highlighting the importance of a cool sleeping environment.
We studied sleep in menopausal women and men 45+ with Pod temperatures OFF vs. ON
To understand how the Pod affects core body temperature and cardiovascular recovery during sleep, 46 postmenopausal women and similarly-aged men (average age: 56 ± 6 years) slept for 1 week each with Pod temperatures OFF vs. ON.
HR and HRV were also measured by Oura rings. Once during each Pod temperature condition, core body temperature, a measure of the temperature of your body’s deep internal organs, was measured using ingestible thermometer pills (see image below). We compared how core body temperature, HR, and HRV changed throughout the night when the Pod was OFF vs. ON.
Core temperature pill: Showing the pill participants received (quarter added for scale).
The results are in: The Pod lowers core temperature, improving HR and HRV
The Pod reduces core body temperature during sleep
With Pod temperatures ON, average core temperature was ~0.2 °C lower across the night, compared to Pod OFF (see Figure 1). For context, this reduction in core body temperature is equivalent to the effect observed in people practicing calorie restriction, a lifestyle known to promote longevity.
This core body temperature reduction is also seen in those using high heat capacity mattresses; however, the lower core body temperature largely occurs in the first half of the night vs. the entire night, and there are no reported improvements in HRV (ref). Alternately, the Pod cools the entire night, further enhancing cardiovascular recovery.
Figure 1. Core temperature difference (Pod OFF vs. ON) in the Night phase (first half of the night), Dawn phase (second half of the night), and the entire night. Bars represent the average of all subjects ± standard error (SE). The values underneath the bar indicate the average core temperature decrease change for that period of time across subjects. Night and Dawn Phases were defined based on each participant’s midpoint of sleep.
Cardiovascular recovery improves for older adults sleeping on the Pod
Sleeping on the Pod led to an average increase in HRV by 14% (mean ± SD = +2.4 ± 14.4 ms) and a decrease in resting HR of 4% (mean ± SD = -2.4 ± 4.2 bpm). Similar changes were seen in the Night and Dawn phases (see Figure 2).
Because HRV naturally declines by 10-15% per decade, older adults may be able to reduce the natural effects of aging by sleeping on the Pod.
Figure 2. Percent change in HRV from Pod OFF to ON for Night Phase, Dawn Phase, and the entire night. Bars represent the average of all participants ± SE. The values listed above the bars are the mean % change for that Phase of the night.
Figure 3. Percent change in HR from Pod OFF to ON for Night Phase, Dawn Phase, and the entire night. Bars represent the average of all participants ± SE. The values listed above the bars are the mean % change for that Phase of the night.
Lower core body temperature, thanks to the Pod, leads to better cardiovascular recovery
Participants who had larger reductions in nighttime core body temperature had better cardiovascular recovery. Specifically, during the first 4 hours of the night (i.e. Night Phase), lower core body temperature resulted in higher HRV (see Figure 4), whereas a lower core temperature across the entire night led to lower resting HR (see Figure 5).
Figure 4: Percent change in HRV from Pod OFF to ON is moderately related to the change in core temperature change (°C) from Pod OFF to ON during Night Phase (r= -0.39; P<0.01). Each datapoint represents one participant.
Figure 5: Percent change in HR from Pod OFF to ON is moderately related to the change in core temperature change (°C) from Pod OFF to ON across the night (r=0.51; P<0.001). Each datapoint represents one participant.
Why it matters
Higher HRV and lower HR during sleep are linked to better next-day readiness and long-term cardiovascular health. Generally, a higher HRV is considered healthier, and changes in your HRV can indicate how well-rested you are, both physically and mentally. [To learn more about HRV see here]. In contrast, lower resting HR is associated with better health. For context, a reduction of 1 bpm in sleeping HR is equivalent to a 1.6% reduction in risk of death from any cause (ref), so the results we are seeing here (a 2 bpm average decrease in HR) is equivalent to a 3.2% reduction in death from any cause.
For the first time, this study connects the Pod’s cardiovascular benefits to a physiological mechanism: lower core body temperature during sleep.
Appendix: Study details
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Participants: Post-menopausal women with and without combination estrogen-progesterone hormone replacement therapy and age-matched men (total n = 46; mean age 57 ± 6 years).
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Design: Within-subject comparison, seven nights of Pod OFF vs. seven nights of Pod ON, in randomized order.
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Measurements: Sleeping HRV (RMSSD, ms) and sleeping HR (bpm) from Oura ring; core temperature (°C) from ingestible sensors (Body Cap) over ~24 hours during each Pod temperature condition.
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Statistics: Repeated-measures analyses compared the change values in core temperature, HR, and HRV for Pod OFF vs. ON. Additionally, Pearson r correlations were used to assess the relationship between the change values from core temperature vs. HR and HRV. An alpha of P<0.05 defined significance.
