HR sensor low readings

Hr Wrist Monitor its not reliable at all during intesity workouts. In the image you can compare External HR monitor (Coros) VS F8 wrist monitor during a 300m strides.

Known issue with Garmin HR algorithm making it too slow to recognize HR increase.

Has been often reported and proved many times during this year but it is either ignored or dismissed without proper solution, as can be seen here as well: https://forums.garmin.com/outdoor-recreation/outdoor-recreation/f/fenix-8-series/391655/when-will-garmin-finally-work-on-the-fundamentally-flawed-optical-hr#pifragment-1292=2

Do not expect that you will receive any help here, you will not get any. Ask for Garmin support to help, they will not be able to help you but then you can request replacement watch since some watches obviously have HR issues but this is something that Garmin or people too invested into Garmin do not want to admit.

same problem here. I'll wait for new FW maybe it would help. For now I'm not using Fenix at all and went back to AW. If  the problem will still be as bad as it is now, I will probably request a replacement. 

It's definitely a software issue.

I said that long time ago, but still am treated like a Garmin bashing person instead of person who points out to problem that needs to be fixed. 

Today had the same. Easy run with three ten second all out sprints (after 40 minutes). My heart rate went down during the three sprints. Crazy and not how my forerunner 945 before measured my heart rate. How they fix this ASAP!

don't bother, it will only ruin your stats.  Get yourself an ECG strap. It will takie time for them to fix that if ever. It's really shameful that flagship have so basic problems.

Vizi said:

I said that long time ago, but still am treated like a Garmin bashing person instead of person who points out to problem that needs to be fixed. 

You are treated like a garmin bashing person, because you are a garmin bashing person... lol

You have bashed garmin in many many threads on this forum. Sure there have been some issues over the years, and there are a small percentage of people who got defective watches, but garmin usually fixes most of the critical issues in an acceptable amount of time (most of the time).

Concerning heart rate, I never really had any major heart rate issues, and have been comparing garmin to apple watches and chest straps for years. I will say that the apple watch heart rate sensors have a very slight edge over the garmin, but not even enough to matter in most cases. Even chest straps get wonky every once in a while, and I have garmin, polar, and suunto chest straps.

So how do you explain this? Seems like a major issue to me. Even if heart rate follows the intensity delivered it should always show up....

Mine works fine...