We have recently released an algorithm update that impacts our calorie burn estimation.
This update primarily impacts periods of time in which your heart rate is between 30% and 40% of your heart rate reserve (your heart rate reserve is the range from your resting heart rate to your max heart rate), which is above resting/restful activities. The types of activities most impacted are those activities during which you are definitely active but not working particularly hard, things like carrying heavy groceries, washing the car, or playing fetch with your dog. This update has no impact on heart rates below 30% of your heart rate reserve and minimal impact on high-intensity exercise. WHOOP is always conducting and implementing research in an effort to maintain our position as the most accurate wearable available.
Working within the limitations of a wrist-worn device, calorie estimates using HR have been shown to far outperform those using acceleration (motion) alone.
To guarantee the best possible signal (and therefore HR and Calorie accuracy) it’s important to make sure your strap is sitting flat against your arm and is tight enough to not move around even with vigorous motion.
We want our users to know and understand what they are fueling their body with, but counting calories can become very cumbersome, so we recommend not to focus too highly on the exact numbers. The Food and Drug Administration allows a 20% margin of error on the calories presented on nutrition facts panel, so just be aware counting is not everything and at the end of the day, it is about how you feel and perform that is what matters most!