HR while swimming with wrist worn external device

Thanks. I know it works well with Garmin chest strap but there seems to be an issue with wrist worn device.

You can see this thread in the F3 forum:

https://forums.garmin.com/showthread.php?324350-Fenix-3-amp-Mio-Link-Pool-swimming

Don't get a Mio Fuse or Vivosmart etc. because the whole reason that the Fenix doesn't record HR while swimming is it is grossly inaccurate and the same holds true for them. Tiny bits of water refract the green light in weird ways between your skin and the camera and cause the view of the bloodflow to be messed up and it doesn't record accurate numbers. You can trick a Fenix 3HR (and I assume a 5) into recording in the water by putting it in run mode (obviously won't record strokes) and you'll see the HR will be very messed up. DCRainmaker did a bunch of tests, the results were useless HR for most of the swimming. Occasionally it would be accurate for short times but then go way off track.

The *only* way to get accurate HR in water is a chest strap.

Thanks for your input. I saw the article from Ray. Yes, it doesn't make any sense to lose the swim metrics to get inaccurate HR.

However some people are happy with the approximate HR they have from the Fuse while swimming although many people reported inaccurate data. I exchanged a few messages with a guy would wears the Fuse very tight and gets decent results.

Thanks for your input. I saw the article from Ray. Yes, it doesn't make any sense to lose the swim metrics to get inaccurate HR.

However some people are happy with the approximate HR they have from the Fuse while swimming although many people reported inaccurate data. I exchanged a few messages with a guy would wears the Fuse very tight and gets decent results.

The issue here is if you wear the Fenix very, very tight it *might* give reasonable HR numbers sometimes but Garmin is a huge company and if they allowed it, even with a "warning" that the numbers might be inaccurate they will get huge amounts of support calls and complaints when it isn't accurate. I doubt very much you will see Garmin enable optical HR tracking while recording swim data until they are confident that the numbers will be accurate the majority of the time for the vast majority of users and the technology just isn't there yet. People like us (and Ray at DCRainmaker) would love to have the option to turn it on and accept sometimes erratic numbers but its just too much of a headache for Garmin.

If you want HR during swimming there is only one actually good option with wrist watches today. And that is Garmin-Swim strap. I have used Polar, Suunto, and Garmin-tri+swim and only one that actually stays put during turns and gives reliable data is the swim strap. In any case I would still use HRM-Tri, Polar or suunto HR strap over any optical one while swimming.

If you want HR during swimming there is only one actually good option with wrist watches today. And that is Garmin-Swim strap.

I agree. The HRM-Swim works great.
I have used a Scosche Rhythm optical sensor worn next to a Fenix 2 or 3 for swimming, and that worked reasonably well too, unless the water was really cold. Connect won't show the HR data of a swim activity though, unless the data from a HRM-Swim.

Don't get a Mio Fuse or Vivosmart etc. because the whole reason that the Fenix doesn't record HR while swimming is it is grossly inaccurate and the same holds true for them. Tiny bits of water refract the green light in weird ways between your skin and the camera and cause the view of the bloodflow to be messed up and it doesn't record accurate numbers. You can trick a Fenix 3HR (and I assume a 5) into recording in the water by putting it in run mode (obviously won't record strokes) and you'll see the HR will be very messed up. DCRainmaker did a bunch of tests, the results were useless HR for most of the swimming. Occasionally it would be accurate for short times but then go way off track.

The *only* way to get accurate HR in water is a chest strap.

I did pretty well with a Mio Link on my wrist, when paired to Ambit2. Sometimes it would wander off, but it generally gave good HR data, and you could display it in real time. So, I could check out my HR coming off the wall in long sets. Loved that capability. Miss it with my F3HR.

I did pretty well with a Mio Link on my wrist, when paired to Ambit2. Sometimes it would wander off, but it generally gave good HR data, and you could display it in real time. So, I could check out my HR coming off the wall in long sets. Loved that capability. Miss it with my F3HR.

My only concern was F5 or F5X but now I see its not possible to record HR while swimming even with an external optical HR I'll still wait for the fw upgrade of the Suunto Sparta and DC's comments on it...

Currently waiting patiently for a Fenix 5 as my Fenix 2 gets nearer to its deathbed day by day.

Enabling the optical HR sensor in swimming would be great. I'm sure there could be a way for Garmin to implement this and acknowledge the accuracy isn't great. I swim masters and forever get the coach asking us all what our heart rate is after a max effort set and it would be nice to get it off the watch. I wonder if a mode where the sensor was enabled while in the rest interval to display a current HR value could work. The wrist should be steady with no water flowing about it, even out of the water at this point so should stand a much better chance of getting a good signal.

Currently waiting patiently for a Fenix 5 as my Fenix 2 gets nearer to its deathbed day by day.

Enabling the optical HR sensor in swimming would be great. I'm sure there could be a way for Garmin to implement this and acknowledge the accuracy isn't great. I swim masters and forever get the coach asking us all what our heart rate is after a max effort set and it would be nice to get it off the watch. I wonder if a mode where the sensor was enabled while in the rest interval to display a current HR value could work. The wrist should be steady with no water flowing about it, even out of the water at this point so should stand a much better chance of getting a good signal.

I agree with everything you said but I doubt Garmin will do it because even if they warn on accuracy they will get complaints. Why not use the HRM-SWIM which works great for lap swimming?