Too high heart rate while Rope Jumping ~160bpm (SW:6.00 HW: Fenix 6s Sapphire)

Are you using the WHR or a strap?  I found the bouncing and wrist movement doesn't work well with the WHR.

Yes!! Fist pump! Another heart rate problem thread...

support.garmin.com/.../

Yes, rope jumping is going to involve a LOT of wrist movement, potentially allowing the watch to move on the wrist, and external light to enter the sensor in a rhythmic way, leading to false measurements.

To reduce movement of the watch, try wearing the watch on the fleshy part of the wrist well away from the wrist bone with the band pretty tight. With so much movement, this may not solve the problem, but is definitely worth trying.

Same problem for me in downhills, ways down during trail running activity... too high HR values... I should die several times, about 20 bpm more than my max HR. Now, I always use Polar oh1, it works well, bye bye fenix buggy WHR.

Since i have the same problems with running uphill (HR too low) and downhill (HR too high). As i have the problem pretty much with every training my assumption was that Garmin use a weird algorithm to calculate the HR. This was now confirmed with the last answer form the Garmin Support. Have a look here under False Heart Rate Detection: https://support.garmin.com/en-US/?faq=xQwjQjzUew4BF1GYcusE59

I noticed the same anomaly when running uphills, HR too low...

Rope jumping has to be probably the WORST activity to expect WHR to be accurate. Wrist flexion and bouncing prevent the watch from maintaining a stable plant on the skin and allow light under the watch.  Pair a chest strap or a Scosche.

Irony is that  i used to jump rope with my fenix 3hr all the time and did not have irratic readings from the wrist. Or that i thought i did. At the same time,  i would argue that jumprope, depending how you hold the handle, requires very little weist movement and more arm movement once your momentum is going. I reviewed videos on youtube, is within acceptable movement IF your watch is tight and doesnt move when you prep it before hand, twisting wrist. My 2 cents and previous experience.