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Heart rate values inaccurate when holding my leg.

Hey everyone, 

I have a peculiar problem which I wonder if anyone else has experienced.

While I am sitting at my desk during work I like to grab hamstring/under leg and let my restless legs hit against my palm (weird but sensory and whatever).

I notice when I do this for too long and look at my heart rate its suddenly reading upwards of 140-200bpm. 

I haven't officially tested this but seems to always happen around the same time, I get quickly concerned and then manually check my pulse to know I'm not about to die. 

Has anyone else experienced this or know why its occurring, my first guess is that its picking up two different blood pulses, one from my wrist and one from my leg.

It is quite annoying for someone who is data driven to see massive spikes in heart rate and stress during the day.

Thanks! 

  • It's normal.  The Heart Rate monitor uses motion based algorithm to estimate the Heart Rate.  The LED sensors are only used sporadically to increase battery life because those LEDs are power hogs.  The real Kicker is that the Algorithm is based on the Average US male, a population that is 40% Obese.  It's why if you get up to answer the door and only walk 10 or 15 feet you will see your heart rate jump into the 110-125 BPM range.  To be blunt if you want truly accurate Heart Rate readings then wear a chest band.

    For anyone doubting this stand still and swing the arm wearing your watch and start swinging your arm like you are walking a 13 minute mile.  Do this for 5 full minutes and then take a look at your Heart Rate.  What you will see is a clear indication that the wrist based monitors are pure Fiction.

    I will also note that I started with Gamin Forerunners with the Forerunner 15 where the only heart rate option was a chest monitor.  One notable feature of the Forerunner 15 was that you could NOT spoof the step counter by swinging your arm.  If you needed 200 steps to hit your daily goal at the end of the day you couldn't get there by brushing your teeth vigorously, you actually had to go out and walk 200 steps.  I will also note that the step counter actually recorded steps taken with your hands in your pockets or pushing a grocery cart and even with the watch in your shirt pocket.  The forerunner 15 didn't use the wrist swing to count steps it was a 3D sensor that used vertical motion in combination with the forward surges produced by actually walking.