I’ve been a dedicated WHOOP user for a while now, but I’ve consistently run into frustrating issues with the device’s heart rate (HR) accuracy during strength training sessions. It’s something that’s been widely discussed, and in my experience, it’s not just suboptimal—it’s often wildly inaccurate, leading to skewed strain and recovery scores that don’t reflect my actual efforts. I’d love to hear others’ thoughts and hopefully get some visibility from the WHOOP team on potential improvements.
First off, a positive note: I appreciate how WHOOP already enables calibration for the Blood Pressure Insights feature using a blood pressure cuff. This got me thinking—why not extend a similar calibration option to the optical HR sensor specifically for strength training? Users could pair it with a reliable chest strap (like my Polar H10) during a session to fine-tune the readings. This would make a huge difference in reliability without requiring hardware changes.
To highlight how bad the accuracy can be: In my workouts, the WHOOP’s HR readings frequently lag, spike erroneously, or flat-out miss the mark compared to a chest strap. For example, during compound lifts like squats or deadlifts, I’ve seen discrepancies of 20-40 bpm or more, where the device underestimates intensity during reps and overestimates during rests. It’s not just me—I’ve noticed this has been a common complaint since the 4.0 launch, and if anything, it feels like it’s deteriorated slightly with software updates, perhaps due to algorithm tweaks prioritizing other activities.
This poor HR tracking also negatively affects the WHOOP Age feature (which estimates your biological age), since the device can’t reliably capture those high HR spikes needed for accurate heart rate stages and zones. It artificially undercredits me even when I do hit those intense HR peaks, potentially skewing my physiological age higher than it should be and undermining the insights into my long-term healthspan.
I’ve tried the often-recommended workaround of wearing the device on the bicep, which does help a bit with HR stability. However, this directly conflicts with WHOOP’s guidance to wear it on the wrist for accurate velocity tracking in strength sessions, which is crucial for calculating muscular strain properly. It’s a no-win situation: prioritize HR accuracy and lose out on strain metrics, or vice versa.
And before anyone points to limitations of optical sensors in general— that’s not the full story. My Apple Watch, worn on the wrist, aligns almost perfectly with my Polar H10 chest strap during the same strength workouts, with minimal deviations even under heavy load or sweaty conditions. This suggests the issue is more about WHOOP’s specific sensor implementation or algorithms during grip-intensive, high-movement activities like weightlifting.
WHOOP is an amazing tool for overall health tracking, but these HR inaccuracies during strength training undermine its value for serious lifters. Implementing user calibration could be a game-changer. Has anyone found better solutions, or WHOOP team, is this on the roadmap?
Thanks for reading!