Resting Heart Rate (RHR)

What Resting Heart Rate Measures

RHR reflects how much work the heart is doing to circulate blood when the body isn't asking it for anything extra. The sinoatrial node fires on its own, and two competing branches of the autonomic nervous system pull that rhythm in opposite directions: the parasympathetic branch slows it down, the sympathetic branch speeds it up.^[1] Because RHR sits downstream of that push and pull, it moves with anything that shifts autonomic balance, including hormones, sleep, illness, and temperature.

How It's Measured

RHR used to mean a single seated pulse count first thing in the morning. Consumer wearables measure it differently now: they sample heart rate continuously overnight during sleep and run it through a device-specific algorithm rather than reporting one raw number. Garmin, for example, calculates the lowest 30-minute average within a 24-hour window, while Whoop weights its overnight average toward slow-wave sleep, and Oura averages heart rate across the full sleep period in short segments. A 2025 validation study comparing five consumer devices against a medical-grade ECG found the ring-based devices came closest to that reference, with mean errors around 1 to 2 bpm.^[2]

Why People Track Resting Heart Rate

Because RHR is simple to capture passively every night, it's one of the easier biometric threads to line up against a menstrual cycle. Progesterone, which rises sharply after ovulation, shifts the autonomic nervous system toward its more sympathetic, activated side, and that shows up as a modest overnight RHR increase in the luteal phase. It's one of the better-evidenced cycle-linked biometric patterns, alongside the related drop in heart rate variability (HRV) over the same window.

For the full picture of how RHR and HRV move together across a cycle, including how much each typically shifts, see our deep dive on HRV and Resting Heart Rate Across Your Cycle.

How Go Go Gaia Tracks Resting Heart Rate

Go Go Gaia doesn't run its own heart rate sensor. It syncs the resting heart rate your Apple Watch or other connected wearable already calculates through Apple HealthKit, then charts it day by day alongside your logged cycle phase, symptoms, and other biometrics like HRV and basal body temperature. You see how they move together instead of checking each one in a separate app.

What the Research Shows

A 2024 analysis of over 45,000 real-world menstrual cycles from wearable data found resting heart rate at its lowest around day 5 of the cycle and its highest around day 26, an average swing of roughly 2.7 bpm between the two points.^[3] A smaller, controlled study using wrist sensors during sleep across 274 ovulatory cycles found a similar pattern at finer resolution, with mid-luteal pulse rate averaging 3.8 bpm higher than during menstruation.^[4]

The mechanism traces back to progesterone. Within-person studies tracking the same women across cycles found that higher-than-usual progesterone reliably predicted a shift toward more sympathetic, less parasympathetic autonomic activity in that same person, with estrogen showing no comparable effect on its own.^[5] Progesterone is also thermogenic, raising core body temperature slightly during the luteal phase, a metabolic shift that runs alongside the RHR increase.^[6] For more findings on how this pattern holds up across different studies and devices, see our HRV and Resting Heart Rate piece.

Related Terms

Frequently Asked Questions

Educational information based on published sources. Not medical advice. For personal concerns, please consult your doctor.

Does resting heart rate change across the menstrual cycle?

Population-level research finds resting heart rate runs a few beats per minute higher in the luteal phase, after ovulation, than in the follicular phase, tracking the rise in progesterone. A large real-world dataset of over 45,000 wearable-tracked cycles found an average swing of about 2.7 bpm between the cycle's lowest and highest points.

How do wearables calculate resting heart rate?

Modern wearables no longer rely on a single seated morning reading. Devices like Oura, Whoop, and Garmin continuously sample heart rate overnight during sleep and apply their own algorithm, such as the lowest sustained average in a 24-hour window, to estimate resting heart rate, then report one daily figure.

Is resting heart rate the same as heart rate variability (HRV)?

No. Resting heart rate counts how many times the heart beats per minute at rest, while HRV measures how much the timing between individual beats varies. They're related and both shift with the menstrual cycle, but they move independently and reflect different things about the autonomic nervous system.