How does WHOOP track/monitor your Heart Rate?
WHOOP utilizes a method called Photoplethysmography, or PPG, to track your Heart Rate on a 24/7 basis.
PPG monitors heart rate by shining light through the top layer of your skin. Various factors, such as skin, muscle, fat, and blood reflects some of the light back into the WHOOP Strap’s sensor. The major varying component of this signal is the changing volume of blood under the sensor, caused by your heart pumping blood. WHOOP monitors this signal and converts the changing amount of reflected light (received by the sensor) into a heart rate.
NOTE: While this technique is a proven effective way to monitor heart rate, there are instances, or disruptions, which can corrupt the signal and affect the accuracy of results. In response to combat/prevent these disruptions, WHOOP has developed many proprietary techniques, hardware enhancements, and algorithms to reduce these disruptions and amplify the fundamental signal used to measure heart rate.
Best Practices to Ensure Optimal Signal Quality
Below are some best practices to make sure your Heart Rate is being captured as accurately as possible:
- Make sure the sensor is snug against the skin even during the most intense workouts. It's important that the WHOOP Strap is fit tightly against the skin to minimize/eliminate relative movements of the sensor (against the skin). The sensor should always be snug enough that it maintains constant contact with the skin. To learn more about proper Strap placement, check out this article.
- Some users may have unique anatomical features, or participate in activities which cause large amounts of disruption/noise during the measurement process. In these cases, if you notice a decrease in heart rate accuracy, try moving the Strap up or down your wrist by 1 centimeter. This usually helps to capture more accurate measurements.
- If you feel it's more comfortable, or allows for optimal range of motion in your workout, move the WHOOP Strap up toward the forearm or even on the bicep. Visit our WHOOP Shop Accessories section for customized Strap apparel, such as our bicep bands and hydro bands/sleeves.
- Make sure the sensor is kept clean. Cleaning your WHOOP Strap and sensor (which is waterproof) with warm, soapy water. Some WHOOP athletes choose to do this while they shower.
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