Heart rate - wrist vs chest/neck

[darth_furious]

I got my band this week and been watching my heart rate. I went for a run and I measured HR on my neck at 173. My band said 155-162. I did this a few times and got annoyed at the band. I took a resting pulse and it was almost spot on at 68. When measuring, you can see a flash/pulse with every beat on the band and so I measured my pulse on the other wrist to compare the beats. It is spot on even during exercise.

That made me think: is my pulse different on my chest vs wrist? I looked it up and found the answer: Do wristband heart trackers actually work? A checkup. - CNET

There's another complication, too. By the time blood reaches the capillaries in your wrist, it has already slowed down to a rate that doesn't necessarily reflect your true heart rate -- especially, as Dr. Zaroff explained, at BPMs above 100

The band is accurately measuring your wrist pulse, as accurately as a doctor with his hand on your wrist could measure. However, this pulse is different than your neck or chest (using a chest strap monitor). When using the MS band, I find about 2-3% error at resting(70bpm) and 7-8% when running (160bpm) which is better than the health trackers they tested. People here complain about HR accuracy but it's as accurate as it could be, maybe it's not the band that's inaccurate but you (your wrists)....maybe you should compare wrist (band) to wrist instead of wrist (band) to chest (strap)


[TL;DR] Conclusion: The MS band is VERY accurate in measuring HR for me. The site it measures (wrist) is not as accurate as a chest strap/neck.

 

[DroidUser42]

There's another complication, too. By the time blood reaches the capillaries in your wrist, it has already slowed down to a rate that doesn't necessarily reflect your true heart rate -- especially, as Dr. Zaroff explained, at BPMs above 100

I call bogus. I think the facts have gotten muddled. How can the pulse rate slow down? It can't. Now, getting mushed together to the point that it's hard to read, yeah, I'll buy that. The capillaries effectively create a distributed resistor/capacitor network. That will attenuate the signal (pulse rate) at higher frequencies. But that doesn't change the frequency. It just makes it harder to detect. To say the pulse rate goes down is to say that somehow some pulses disappear. I didn't see any explanation like that.

and that they work only when you're still

What I've found is that they work only when your arm is still. I've also found an area on the side of my wrist that seems to get a good reading.

The article is almost 18 months old - older than the Band. It will be interesting to see if MS had worked out any of those problems. Clever DSP and a year's worth of experience may have come up with something. I'd like to see a update.

But good article. It certainly explains the challenges.