Heart Rate Readings all over the place

cmbauer

macrumors regular
Original poster
Sep 27, 2016
193
74
SO went for a run yesterday, did some max effort intervals. So I would run max effort for 400 meters then recover for 2:30 minutes and did 8 intervals this way. I am wearing a NIke Series 2

I was using the Runkeeper app to do this and my watch was reporting a crazy low Heartrate. The watch was tight on my wrist. I have never had the sensor be off this far on a run. It was reporting under 60BPM even right after the interval when I know my HR was around 190. I checked Heart Watch and it is showing the same information.

Any ideas why it would be so off? Its a brand new ( bought yesterday ) and I loaded a backup of a Nike Watch I had about 2 months ago
 

cmbauer

macrumors regular
Original poster
Sep 27, 2016
193
74
It's never had this issue before when running. It's not like the heart spikes quick to 190 then drops quickly.

I have a Scosche Rythm and also the Twelve South action sleeve and with the action sleeve I know the sensor is capable to keep up with dynamic workouts especially HIIT and CrossFit.

I just never had the sensor act so crazy for just running
 

pedrowerner

macrumors regular
Aug 24, 2016
225
175
Probably sweat is making difficult for the sensor to read your pulse because of refraction
 

Newtons Apple

Suspended
Mar 12, 2014
22,757
15,222
Jacksonville, Florida
SO went for a run yesterday, did some max effort intervals. So I would run max effort for 400 meters then recover for 2:30 minutes and did 8 intervals this way. I am wearing a NIke Series 2

I was using the Runkeeper app to do this and my watch was reporting a crazy low Heartrate. The watch was tight on my wrist. I have never had the sensor be off this far on a run. It was reporting under 60BPM even right after the interval when I know my HR was around 190. I checked Heart Watch and it is showing the same information.

Any ideas why it would be so off? Its a brand new ( bought yesterday ) and I loaded a backup of a Nike Watch I had about 2 months ago
Join the club of users who have found the sensor for HR to be almost nonfunctional at times. I can go for a run and check my HR and it is either nothing or some crazy number like 40 or 60 bpm. Does not matter how I wear the devices and it has remained the same though three different models of the AW.

Apple need to replace the sensor in it next model and look at what Garmin and Fitbit are using as I can wear these devices, even loose, and they still track my HR.

Do not get me wrong, I like my AW but the HR sensor has been a failure for me.
 

ftaok

macrumors 603
Jan 23, 2002
6,203
1,229
East Coast
I wonder if the accuracy (or lack thereof) on the AW sensor is dependent on how hairy one's arms are. For me, the AW's HR sensor has been excellent. It's within a few beats of my Polar straps and I never forget to bring it along (like I sometimes did with the straps).

Also, there's nothing to wash, or more importantly, there's nothing to forget to wash. The stench of the sweaty strap that's been left in my gym bag for two days was amazing.

Anyways, back to my original point. I do not have hairy arms. When I sweat, the sensor doesn't lose contact with my skin, unless I forget to wear the watch one click tighter.

I wonder if folks with very hairy arms, when sweaty, have enough interference with the AW "rounded" sensor that it loses contact. Hmmm.
 

Newtons Apple

Suspended
Mar 12, 2014
22,757
15,222
Jacksonville, Florida
I wonder if the accuracy (or lack thereof) on the AW sensor is dependent on how hairy one's arms are. For me, the AW's HR sensor has been excellent. It's within a few beats of my Polar straps and I never forget to bring it along (like I sometimes did with the straps).

Also, there's nothing to wash, or more importantly, there's nothing to forget to wash. The stench of the sweaty strap that's been left in my gym bag for two days was amazing.

Anyways, back to my original point. I do not have hairy arms. When I sweat, the sensor doesn't lose contact with my skin, unless I forget to wear the watch one click tighter.

I wonder if folks with very hairy arms, when sweaty, have enough interference with the AW "rounded" sensor that it loses contact. Hmmm.
I have very little hair on my arms but a friend of mine had a LOT and he actually shaved the spot where his watch hugged his wrist.
 

Alvi

macrumors 65816
Oct 31, 2008
1,203
307
Mars
I was doing some pretty intense lifting at the gym earlier today and I my readings were off too, I mean, I know it's not cardio but there's no way my heart rate is 60-70 when I'm pushing everything to the limits and sweating like crazy.

I don't think it was always like this tough (and I own my Series 1 Apple Watch since launch day) , I might try to trim the hair a bit around my wrist (even though it's kind of a ridiculous thing to do just because I want my AW to work properly haha)

Is it better to wear it really tight or a bit loose?
 

Newtons Apple

Suspended
Mar 12, 2014
22,757
15,222
Jacksonville, Florida
I was doing some pretty intense lifting at the gym earlier today and I my readings were off too, I mean, I know it's not cardio but there's no way my heart rate is 60-70 when I'm pushing everything to the limits and sweating like crazy.

I don't think it was always like this tough (and I own my Series 1 Apple Watch since launch day) , I might try to trim the hair a bit around my wrist (even though it's kind of a ridiculous thing to do just because I want my AW to work properly haha)

Is it better to wear it really tight or a bit loose?
You need to try both but most will say tight and slightly higher on the wrist. I tried it all even three different watches and get the same inconsistent results. Still wear my watch occasionally but not for the fitness factors.
 

bjet767

macrumors 6502a
Oct 2, 2010
967
313
The sensor is not "measuring" any electrical pulse. It is using a green light and sensor which actually watches the blood movement on your wrist. It has been documented that it works best on lighter skinned and less "hairy" arms. Additionally Apple recommends the wearer have it on tighter because if it moves a lot the sensor observation will be off.

"
How Apple Watch measures your heart rate
The heart rate sensor in Apple Watch uses what is known as photoplethysmography. This technology, while difficult to pronounce, is based on a very simple fact: Blood is red because it reflects red light and absorbs green light. Apple Watch uses green LED lights paired with light‑sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. When your heart beats, the blood flow in your wrist — and the green light absorption — is greater. Between beats, it’s less. By flashing its LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute — your heart rate. In addition, the heart rate sensor is designed to compensate for low signal levels by increasing both LED brightness and sampling rate."


https://support.apple.com/en-us/HT204666
 
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