Garmin

2 lurkers | 218 watchers

larkim Jan 2024 10:18pm, 10 Jan 2024 22,948 posts	0 larkim There's no technical reason why an optical sensor should be more than a beat behind How do you know this? It stands to reason, an optical sensor detects the "pulse" of a beat. What other delay could or should there be?
larkim Jan 2024 10:23pm, 10 Jan 2024 22,949 posts	0 larkim I can see how a software implementation in the optical devices might want to process the data a little slower for smoothing purposes (though equally that could apply to chest straps too) but there's zero reason why on detection of the pulse strength "seen" by the pulse.
Badger Jan 2024 11:27pm, 10 Jan 2024 16,876 posts	0 Badger It stands to reason, an optical sensor detects the "pulse" of a beat. What other delay could or should there be? Could be filtering and Fourier transforming of time windowed data to help extract the peak more precisely, it won't be anywhere near as well defined as the ECG R wave, and probably a lot noisier too. There's a contribution from the time it takes for the pressure wave from the heart to reach the wrist, but that's less than a second (the blood takes longer than that to arrive, but it's the vessels stretching and contracting with the pressure wave that three optical system works with) so much less than what I measured in the link above.
SPR Jan 2024 11:36am, 11 Jan 2024 43,458 posts	0 SPR Optical doesn't detect pulse as I read it. How long the changes it detects take is another matter. pinnaclelifescience.com "The optical heart rate monitors sensors detect small changes in your skin as the blood vessels expand to allow this extra flow of blood. This makes it an accurate measure of heart rate compared with other methods such as ECG (electrocardiogram) or EKG (electro-skeletal graph"
tipsku Jan 2024 11:09pm, 11 Jan 2024 3,818 posts	0 tipsku For me optical sensors at the wrist are pretty useless most of the time as they tend to be up to 30 BPM away from what the chest strap measures. It's either sweat in summer or extremely cold hands in winter (I suffer from Raynaud's syndrome, a blood circulation disorder in the extremities that makes them go white and numb so good luck detecting any blood flow as there is practically none for a while) so chest strap is the way to go. There's only a 2-3 months window in the year when it could work. This said, I am tempted to try the Coros upper arm optical band as I have heard from testers that it's more reliable than optical sensors at the wrist and more comfortable. I had my fair share of chafing under my boobs so I'd be happy to avoid that in the future. Blister plasters at strategic places have helped to some degree but when they slip, it's back to pain. Moreover, the Coros is cheaper (half the price of the new women's Garmin HRM) and has a rechargeable battery unlike the coin batteries that the Garmin HRM needs.
SPR Jan 2024 11:26pm, 11 Jan 2024 43,460 posts	0 SPR You get more for the same money with the Polar Verity Sense if I read things correctly.
Badger Jan 2024 8:43am, 12 Jan 2024 16,879 posts	0 Badger And pretty much everything higher up the arm is more accurate than the wrist even for folk who don't have Raynaud's, so definitely worth a shot for you tipsku Does the optical lag bother people? Heart rate lags effort anyway so for me another few seconds is neither here nor there, really.
larkim Jan 2024 8:58am, 12 Jan 2024 22,965 posts	0 larkim Agreed about a few seconds of lag, though I suppose if you were doing a MaxHR test and you want to see what the peak is at the point at which you hit "stop" on a watch maybe you'd capture the data too early. Pretty niche though. I don't think anyone does max effort intervals to HR, and whilst the data captured post-activity is nice to see not sure it has any real world use if we're talking 2 or 3 BPM different between different approaches. 5 or 10 would be significantly worse. My take away is broadly that optical, whether it is baked into a watch or in a stand alone device, is more than good enough. It all comes down to whether the device you use fits well enough. And like I say, I've had more reliability with optical devices than chest strap devices, both as watch-based HRM and stand alone devices, so I'm definitely in the "optical for the best solution" camp.
Big_G Jan 2024 9:04am, 12 Jan 2024 3,208 posts	0 Big_G Might be for you larkim, but I think you are one of the lucky ones that it works for in the watch. But we’ve been over this so many times. For me the watch sensor is basically a random number generator flicking between 120 and 180bpm when I know I’m running at, or very close to, 140. And yes, I have the watch fitted properly, etc.
larkim Jan 2024 10:40am, 12 Jan 2024 22,966 posts	0 larkim Oh yes, I know I'm lucky with the watch. But not with the arm band - I was actually a little disappointed having bought an armband monitor about 12 months before I got a new watch with built in HRM that the watch worked so well, as I'd read constant stories about it not working for most people! Armbands are pretty flawless (unless I'm missing some feedback about them not working well for some). But that's my broad point; optical (when placed properly, which may or may not be possible for watches for individuals due the peculiar makeup of their bones and, worryingly, skin tone) works equally as a good as chest strap as a technology. And getting back to the sports bra adapted one, any bra-wearing individual who wants to monitor HR effectively has had the armband optical sensor option available to them for a long time now, so it feels a little odd that Garmin should choose to try to solve the comfort problem now when a perfectly reasonable solution has already come to market and become quite established.