I’ve noticed a number of posts in the WHOOP community discussing inaccurate heart-rate readings during power or weight-lifting sessions—specifically, that WHOOP often fails to capture sudden spikes in heart rate. I recently ran into the same issue, and after paying close attention during my workouts, I think I may have identified part of the problem.
It seems that whenever I perform exercises with large or rapid arm movements, my heart-rate reading freezes and only updates once I stop moving. This makes me think WHOOP is applying a motion-smoothing algorithm that discards optical-sensor data whenever the accelerometer/gyroscope detects sudden movement. This would explain why WHOOP performs very poorly during strength training or explosive lifts, yet works well for activities with more stable, sustained heart-rate patterns.
I understand the reasoning—optical sensors are less reliable when the device is undergoing sudden acceleration. But during strength training, heart-rate changes are also rapid, and even if the readings are a bit noisier, seeing those spikes is still valuable feedback. All sensors require integration time, so high-error readings in moments of sharp HR change are normal and expected.
That’s why I’m wondering: could WHOOP add an option in the Strength Trainer to reduce or disable motion smoothing? Even if strain calculations continue using smoothed data, having access to real-time, unsmoothed heart-rate spikes would provide much more meaningful feedback during lifting sessions and help confirm when I’m hitting my intended intensity.
Curious if anyone else has observed this, or if WHOOP might consider offering users this level of control.