Stamina field for running

I got my first Garmin watch (Epix 2) a few weeks ago. I love it very much (former Apple Watch user) but I would not buy it just for the Stamina. In my case I believe it greatly overestimates my running ability because I'm not an athlete nor a professional runner...Today for example, I went out for a 10K. There were around 32.5 Celsius degrees in the shade and I would say near 40 in the direct sunlight. Humidity was very high as well. When I completed the run I was so exhausted that I was afraid of fainting. Stamina field at the end was around 41%.... So you see a pretty high value. Maybe it just requires more time to fine tune (I ran just 66Km so far with the Epix). I heard that is more precise for long runs (>15-20km) but I don't want to die just to test it

I have run a few ultras with the Epix and Stamina hits 0 long before I have finished racing and yet I finished.

Same as for biking. For long runs/bike tours it hits 1% after about half the duration and I don't feel tired or exhausted at all. So at

the moment a useless metric for me. 

Doing anaerobic intervals looks pretty accurate to me...at the end of first intervals i'm still ok but the latest are not so funny

While it's nice to see i'm not using it at all because i don't see any reason to say "let's run until i reach 30% or 1% of the stamina" just to make 2 random examples.

Maybe it could be more useful for people that do really long runs.

Are these 1min intervals at around 3min/km pace?

nice!

Stamina is not really that useful for long runs, the goal on these is to run at consistent pace, you will know yourself what that pace is. I think 5k/10k pace and long intervals is probably where it’s most useful, but what I do, is just set the virtual pacer to whatever I think I can do and use the overall ahead/behind as the main metric to follow. And I monitor HR to make sure I’m not going to blow it.

just my personal opinion of course. 

I use Stamina mainly for recovery purposes between intervals. I hadn't thought I'd use it so much, but I really like it.

The stamina drain also appears to be spot on for me (although I don't really look at the stamina gauge during intervals, I only look at my power output and the timer, hoping that the pain will end soon ). I had a really poor 10 min. zone 5 ride recently and my body noped out after 5 minutes. Stamina hit zero around that time. 

1min yes but a bit slower with an average of 3:30 and i'm already like 30 seconds faster than the target

If you're an expert runner i guess you will know the pace for long runs but otherwise knowing how much you should be able to do with x pace looks pretty important to me. I don't want to say it's not important for 5/10k as starting too fast can lead to bad final results. 

This was a threshold run and i was not able to run it until the end without a quick break of 10-15 seconds but the stamina was ok. Not sure why i had to stop that time as it happened a few weeks ago and i didn't have a Threshold run recently.

Thank you for the feedback. Over the last couple of years, the metrics that I have got from my Fenix 6 have been good. Like today I ran 10km training run (I didn't plan to but kept going as I felt fine). I matched the predicted race time for the 10km.

I do wonder what it would have said about my stamina. It seems like most metrics get better the more data they have. 

I am still on the fence about the upgrade, I will wait now until after the summer holidays.

But I do like data, as I think it has made me a better runner and MTBer.

The stamina % is not that useful per se as a number, but the predicted distance and time that can be sustained moving forward is useful, whether you are doing long/short intervals, or long/short runs.

I think stamina-led distance and/or time shines in any race/run situation.

I agree with the other posters that combining the stamina-led distance or time to go with a pace pro strategy or a virtual partner is the way to go: if you over- or under-shoot at the beginning of your run, while your stamina projections might not be fully settled, you might have spent too much energy or lost too much time to fully optimize the run/race. Combined with pace pro, your stamina-led distance or time will let you know along the way if the pacing strategy is adequate.