Measuring Heart Rate

I’ve said it before but it bears repeating.

A man with two clocks never knows what time it is.

Today I went out with my Polar Chest Strap and Samsung Gear Sport watch. I got two very different sets of data. Normally, I would trust the chest strap over the watch since the watch sometimes runs too high. This time I trust my watch over the chest strap. Why?

Two charts

Turns out that Strava can export a GPX file which can be read by EXCEL. (EXCEL complains about the data a few times but opens it OK). Here’s the two charts.

Judging by Past Performance

I’ve walked up the same hills before and have an idea of what happens with my heart rate. By one mile I’ve gone to the post office and started walking back up a hill. The Polar has my heart rate at 70 which seems way too low. The Samsung has my heart rate at 100 or so which makes more sense.

Judging by Rate of Perceived Exertion

The last half of the Samsung data has my heart rate in my MAF range (112-122). That makes sense given where I was in the walk and my rate of perceived exertion. Here’s the MAF range added to the Watch data.


The splits show I was behind my normal pace (messing with the monitors plus I was on hills) but not that far behind the pace.


Other than going to the Post Office (upper left circle) I did my typical route.

The pace and elevation data are:


I think I didn’t wet the Polar strap well enough. It was less than 70 degrees and relatively dry so the strap could have been too dry. I didn’t sweat on the walk either.

Next time I will wet the chest strap better.


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