WHOOP Unveils Breakthrough in Menstrual Health Monitoring with New “Cardiovascular Amplitude” Metric

Boston, MA – June, 2025– WHOOP, the human performance company, today announced a major advancement in menstrual health research with the introduction of a new physiological marker: Cardiovascular amplitude. Published in NPJ Digital Medicine (Nature), the study analyzed over 45,000 menstrual cycles from more than 11,000 WHOOP members to quantify predictable fluctuations in resting heart rate (RHR) and heart rate variability (HRV) across the menstrual cycle.

Historically, women have been significantly underrepresented in sports science and physiological research. Despite the menstrual cycle being recognized as the "fifth vital sign," it has largely been monitored through subjective symptom tracking or broad estimations of cycle length. This new study marks a pivotal shift toward objective, data-driven cycle monitoring using wearable technology. 

Key Findings 

1. Cycle-Wide Cardiovascular Trends: WHOOP data revealed clear and predictable trends. RHR reaches its lowest point during menstruation and peaks before the next cycle begins. HRV, conversely, follows the opposite trajectory—peaking during menstruation and declining before the next cycle—suggesting an optimal physiological window for performance.
2. Introduction of Cardiovascular Amplitude: This novel metric captures the magnitude of change in RHR and HRV throughout an individual’s cycle, offering a more nuanced and dynamic measure of menstrual health than static averages.

Personalized Factors: Age, Fitness, and Birth Control

• Age is associated with smaller cardiovascular amplitude, indicating dampened fluctuations in older individuals.
• Members with very high or low baseline RHR or HRV also showed less variation across their cycles.
• Those using birth control pills exhibited significantly lower cardiovascular amplitude, as birth control pills create steady hormone levels which may in turn keep RHR and HRV steadier. suggesting hormone-mediated blunting of natural cycle dynamics.

Empowering Women Through Physiology

By tracking cardiovascular amplitude, WHOOP enables:

• Real-time insights into personal physiology and between-cycle variability.
• Detection of cycle irregularities with significant changes or atypicalness in cardiovascular amplitude.
• Evidence-based dialogue with healthcare providers, replacing subjective symptom logs with concrete physiological data.

Interview time with the WHOOP researchers is available upon request. 

About WHOOP

WHOOP, the human performance company, offers a wearable health and fitness coach to help people achieve their goals. The WHOOP membership provides best-in-class wearable technology, actionable feedback, and recommendations across recovery, sleep, training, and health. WHOOP 5.0 and WHOOP MG offer groundbreaking health innovations, including cardiovascular health features; Healthspan which quantifies Pace of Aging and provides members with their WHOOP Age; and first-of-its-kind wearable Blood Pressure Insights. WHOOP is the perfect health companion for anyone looking to optimize their health and performance. Founded in 2012, WHOOP is based in Boston and has raised more than $400 million in venture capital. WHOOP is available to ship in 56 markets worldwide and the WHOOP app is available in English, French, German, Italian and Spanish (Latin America). WHOOP can be purchased on Amazon across the U.S., U.K., and Australia, as well as Best Buy (U.S.) Dick’s Sporting Goods (U.S.), Flipkart (India) and Virgin Megastore (GCC), and more.  

To learn more or start a one-month free trial, visit whoop.com and connect with WHOOP on Instagram, X, Facebook, LinkedIn, and YouTube. 

Contacts press@whoop.com