Hi everyone,
I recorded my training sessions using the Strength Trainer mode on Whoop, with the band worn on my biceps exactly at the spot recommended by Whoop Support and shown in their official placement graphic. At the same time, I tracked my heart rate with an Apple Watch on the same arm and synchronized the data for direct comparison.
During training, there are frequent, sudden, and short spikes in heart rate, which are typical for intense phases of strength workouts. The Apple Watch clearly displays these peaks. However, the Whoop band either does not show these short-term spikes at all or only displays them in a very dampened way. Instead, the Whoop heart rate reading often remains at a lower value or reacts with a noticeable delay.
According to Whoop’s own documentation, the band measures heart rate 52 times per second, so technically it should be impossible for the device to miss these sudden increases in heart rate. The only plausible explanation is that the raw data is being heavily smoothed or filtered, so that short, training-relevant peaks are suppressed. I specifically used the Strength Trainer mode, hoping that filtering would be minimized in this setting.
Because of this filtering, Whoop registers less time in higher heart rate zones, especially zone 3 and zone 4, compared to the Apple Watch. This could negatively affect the strain score and even the Whoop Age, since the actual training intensity is underestimated.
Especially in strength training and interval workouts, it’s crucial that short-term heart rate spikes are accurately detected to realistically reflect training intensity and load. The current filtering means that these peaks are not recognized, and the actual training intensity is underestimated. This issue has occurred with both my Whoop 4.0, WHOOP 5.0 (which was declared defective and replaced), and the replacement device, so a hardware defect can be ruled out. It seems to be a systematic issue with Whoop’s data processing.
A direct comparison of the time series, see attached plot, shows that the Apple Watch correctly displays the peaks, while the Whoop band does not. I’ve also found numerous reports from other users in this forum describing exactly the same issue, during intense strength training, Whoop fails to display heart rate spikes, while other devices do. This appears to be a widespread, systematic problem.
Is it possible to reduce or disable the heart rate data filtering, especially in Strength Trainer mode? Are there any plans to adjust the algorithms for strength training? Has anyone found a workaround or received feedback from support?
I want to emphasize that I’m generally very happy with Whoop, it motivates me to train more and pay attention to my sleep. That’s why this issue is so frustrating for me, it impacts my training experience and sometimes makes me question whether I want to continue using Whoop. I’m convinced that this problem could be solved relatively easily, especially in Strength Trainer mode, by reducing or disabling the filtering. I would really appreciate it if you could prioritize this topic so that Whoop can provide the best possible support for strength athletes and interval training.
