Apple Watch Heart Rate Accuracy Test

oeagleo

macrumors 6502a
Original poster
Feb 5, 2016
653
368
West Jordan, Utah
Today I did a little experiment, I also have a fenix 6 PRO Sapphire, along with a Wahoo Tickr chest strap. A very accurate combination for counting the heart rate during an activity. I have been using the AW Series 4 for my Tai Chi classes, as it's a lot more convenient than hooking up the chest strap, etc. So today, I decided to use the fenix, and the Tickr to more or less check the "validity" of the AW vs a known accurate combination. The results? AMAZING.
Apple Watch shows a Max HR of 147, average of 120 BPM
Fenix/Tickr shows a Max HR of 142, average of 126 BPM.

Note, these are two separate activities performed on separate days, hence, the difference between the two. The HR charts that were imported into Garmin connect, even shows a max heart rate at the same approximate time during the activity. In other words, according to my somewhat limited experiment, the Apple Watch performs at least as well as the Fenix with a chest strap, without the added inconvenience and comfort. I was amazed. The only discrepancy was in the calorie count, the Fenix/Garmin combo shows a calorie burn of 727 calories, and the Apple shows 434. I'm leaning toward the Apple calorie count, 700+ seems a bit high for only an hour of activity.

Apple Import into Garmin Connect: https://connect.garmin.com/modern/activity/4586912759
Garmin Fenix into Garmin Connect: https://connect.garmin.com/modern/activity/4611896315
 

SRLMJ23

macrumors 68020
Jul 11, 2008
2,119
1,081
Central New York
Today I did a little experiment, I also have a fenix 6 PRO Sapphire, along with a Wahoo Tickr chest strap. A very accurate combination for counting the heart rate during an activity. I have been using the AW Series 4 for my Tai Chi classes, as it's a lot more convenient than hooking up the chest strap, etc. So today, I decided to use the fenix, and the Tickr to more or less check the "validity" of the AW vs a known accurate combination. The results? AMAZING.
Apple Watch shows a Max HR of 147, average of 120 BPM
Fenix/Tickr shows a Max HR of 142, average of 126 BPM.

Note, these are two separate activities performed on separate days, hence, the difference between the two. The HR charts that were imported into Garmin connect, even shows a max heart rate at the same approximate time during the activity. In other words, according to my somewhat limited experiment, the Apple Watch performs at least as well as the Fenix with a chest strap, without the added inconvenience and comfort. I was amazed. The only discrepancy was in the calorie count, the Fenix/Garmin combo shows a calorie burn of 727 calories, and the Apple shows 434. I'm leaning toward the Apple calorie count, 700+ seems a bit high for only an hour of activity.

Apple Import into Garmin Connect: https://connect.garmin.com/modern/activity/4586912759
Garmin Fenix into Garmin Connect: https://connect.garmin.com/modern/activity/4611896315
Thank you so much for doing this, I always wondered how the AW would stack up again a chest strap and another device. I have an AW5 (have had all the models) so I assume this test would apply to the AW5 as I believe they use the same sensor. I hope you do some more testing just to see if the AW continues to be basically right on par with your chest strap and Felix, and to see if you can figure out if indeed the AW is reporting the proper calories burned, or the chest strap/Felix is reporting the proper calories burned. My guess on that is that it might be more around the average of both, so in this case 580, but obviously more testing would be needed to figure that out more.

Once again, thank you for the testing!

It is really good to know that the AW is reporting very accurate heart rate information, as that is vital for a device like this. My AW's (Series 0-5) have always been extremely close (+/- 2-5) when I go to my doctor to get a checkup twice a year and the nurse takes my pulse, and on a few occasions it has matched exactly. Also, when I use my automatic blood pressure cuff (which reports pulse), it is always very close to what is reported by that, and occasionally matches.

Take care, and if you post more, I look forward to seeing the results!

:apple:
 
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Aspasia

macrumors 65816
I wear a Garmin HR strap when using my indoor rower because my AW5 doesn't communicate my HR to the rower's monitor. I do a lot of HR training and it's easier to see on the monitor since it's in front of my face. When I have checked my watch against the monitor, the HR numbers were close and sometimes identical.

Am very pleased with the HR accuracy of the AW because it means I can ditch the chest strap when I start training in my sea kayak.
 

kitenski

macrumors 6502
Jan 30, 2008
279
60
Leeds, UK
I've had mostly good results, but in the UK winter, when running outside it's lost signal, locked on too high a fair few times sadly.

This is quite a graphic explanation!

 
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jhfenton

macrumors 65816
Dec 11, 2012
1,064
625
Cincinnati, Ohio
I've definitely had Apple Watch HR issues during the winter. It usually starts out well, but a few miles in, it often seems to lock onto my cadence (170-190) instead of my HR (most often 125-150). I assume it's a result of capillaries constricting too much due to the cold for a good measurement. I've taken to wearing a Polar HR strap during winter runs. (Wearing the Watch more tightly helps a bit, but on really cold days it is not enough.)

In warm weather and indoors, the Apple Watch HR sensors works remarkably well for a wrist-based solution. I also have a Concept2 rower, and the Apple Watch agrees quite closely with the Garmin ANT+ HR strap that I wear to feed HR data to the rower.

Edited to add an example from last night. I thought it was warm enough, so I didn't wear my Polar strap. It was an easy 6.x-mile run. My HR started off around 130, which was probably accurate. It clearly struggled after that, missing a lot of data and registering in the 170's when it did. Not coincidentally, that was also my cadence, as you can see. (My HR would be in the 170's in a 5K or 10K race, not on a recovery run.)

IMG_0695.PNG
 
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