Vo2Max and Sport Activities

Hi Bashhar. Although the algorithm Garmin uses to calculate vo2max is a secret, I can at least answer part of your question based on my own experiences. First of all, speed and HR are indeed the two most important (maybe even only) variables in Garmin's Vo2max calculation. As far as I know, training load, fatigue etc. is unfortunately not taken into account. I say this based on my own experiences with the measurement and a close analysis of vo2max values in Runalyze. With the 945, heat acclamation IS taken into account, so high temperatures would have a negative impact on your performance and Garmin's formula will somehow compensate for that.

Lastly: when using the activity Trail Running, Garmin does NOT calculate Vo2max, since they find that they are unable to accurately determine what the effect would be on your vo2max. Vo2max is only calculated when selecting the sports profiles for Running and Cycling. It therefore does not matter whether you are on a treadmill or outside, as long as you select this activity type, Garmin will calculate a vo2max for it.

Hope this helps.I personally find the fact that distance does not seem to be in the vo2max equation, really frustrating, because on long runs you tend to have a higher (relatively) HR and I think that the calculations should be adjusted.

7698684 said:

It therefore does not matter whether you are on a treadmill or outside, as long as you select this activity type, Garmin will calculate a vo2max for it.

This is wrong.

For running you will only get VO2max updates from the native Run profile, and only if both HR and GPS speed is available - hence you will not get VO2max from treadmill runs since GPS speed would be zero. (unless they have changed something from the F5+ to the FR945)

Thanks for the reply !

So, if I understand you correctly. You may leave your watch all the time behind and it will make no difference for

- Vo2max estimation

- Recovery

- Training load

- Training Status

As long as you're using your watch ( and a ecg cheststrap ) during workouts. On the another hand,  Body Battery, day stress won't report anything due to the lack of data.

Am i correct ?

Thanks for the reply.

On the 945, the GPS is disabled for "Treadmill". The only way to get some speed data is by using a footpod

witch i did. Apparently in this case, the fit file contain and vo2max detected as well.

Okay, then they must have changed it on the 945.

Btw - do you get updates to your Training Status (Fitness) from treadmill running as well?

I can't tell. I've used a treadmill only a few times ( only on vacation )  and i don't remember.

I'm buying a treadmill this winter

What about Performance Condition - was that recorded during your treadmill runs?

I dit get a Training Effet ( Both aero & anaero ) but I'm not sure I got any Perf Cond ( 0 each time )

You could easily check this by looking at your recorded treadmill runs and see whether there is a Performance Condition graph or not. (...and please do cause I'm curious to know!)

There is no Performance graphs but I'll make another treadmill session in a few days