Anyone see this? Muscle Oxygen Training: Garmin Resting HRV - my experience
Yes, sample size of 1 so maybe its only him, especially since he says garmin watches also give bad HR during exercise. But if this measurement error applies to lots of people and HRV data is wrong on garmin watches this means lots of the metrics on garmin watches that depend on the data may not be as useful as they could be.
BTW this is also my frustration with how reviews are done. Some have long sections dedicated to looking at HR (BPM) accuracy compared to measurements that are known to be accurate. But HRV data? If they do any analysis it seems like they just compare to devices like Whoop and Oura (i.e. devices which don’t export the raw data so can’t really be sure how accurate it is)
Garmin specifically disavows any claims of accuracy for the metrics provided by their fitness products in their disclaimers
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Garmin wearables are intended to be tools to provide you with information to encourage an active and healthy lifestyle. Garmin wearables rely on sensors that track your movement and other metrics. The data and information provided by these devices is intended to be a close estimation of your activity and metrics tracked, but may not be precisely accurate. Garmin wearables are not medical devices, and the data provided by them is not intended to be utilized for medical purposes and is not intended to diagnose, treat, cure, or prevent any disease. Garmin recommends you consult your doctor before engaging in any exercise routine.
I disagree with his first sentence that “the measurement of resting HRV is of critical importance”! It’s an interesting data point, no more, no less. I take a look at it alongside RHR, sleep, what my training load/TSS has been like, what TR RLGL is saying, what Garmin recovery advisor (which is HR-based anyway) is saying, and most importantly how I’m feeling. Most of the time most of those things mostly align. When they don’t it’s an interesting and informative exercise to think about why - if I feel good but all the other metrics are telling me to take it easy then maybe it’s because I’m not really listening to my body because there’s some hard training I really want to do (like a fast group ride) and in the interests of longer term consistency I should probably dial things back a bit. Or maybe there’s some data those metrics aren’t taking into account properly, like I’m on holiday, have no work stress, have been taking naps in the afternoon, etc and actually I’m fine to push through a bit as I have extra recovery capacity.
I think Garmin’s training advice maybe leans a bit too heavily on HRV, but then since I’m only taking is as guidance and choose to ignore it on occasion I’m OK with that.
Optical sensors on watches are never going to be great at measuring HR during exercise, because if your wrist/hand is moving then the sensor-wrist interface is going to be moving around and external light will be getting in there and messing up the data. Whoop’s solution of using an elasticated bracelet is much better in terms of keeping the sensor in one place and keeping light out. Surprised Garmin haven’t brought this out as an option. But if using a Garmin watch and if you care about your training I think you’d always be better off with a separate HR strap, either round the chest or the optical ones on the arm are pretty good these days. FWIW my Garmin HR data at night seems pretty solid, presumably because I’m not moving around and it’s dark so there’s minimal interference with the optical sensor.