Real-time "Time To Exertion"

New Xert user here.

I was mind-blown when I saw how Xert could predict when I would be at my limit. I imported power files from workouts were I really gave my all, and the MPA curve just touched the power curve at the moment where I gave up. Nothing but amazing.

So I bought a Garmin 530 to see Xert metrics when doing outdoor rides. One of the most interesting metrics must be time to exertion (TTE). Please correct me if I’m wrong. As far as I understand, the Garmin app lets you see the TTE at a pre-defined power output, e.g. 500 watts. It would be a lot more useful if this power number was not pre-defined.

Wouldn’t it be interesting to see the TTE for real-time power numbers? Then I could see that I’m going to blow up in X seconds if I continue the current power output. Yes, you can see the current MPA now, but the app does not say when MPA will equal the current power output.


Turns out there is too much variability to use it like that but you can use it with target values such as your 10 minute power and monitor how long you can hold that.

See this post: TTE with no parameters - Support - Xert Community Forum (

Thanks for the answer.

Would dynamic TTE be feasible if it were estimated from the average power from the last 10 seconds, instead of true realtime power (1 second)?

Would just pay attention to the colour of the power reading in the MPA and Power datafield.
From the description I think it does what you want (orange and red tell you roughly how long till exhaustion):

In addition, a colour-coded power display enables quick view of your current power output:

● Blue - Well below threshold

● Green - Just below threshold

● Yellow - Just above threshold

● Orange - 180s or less until exhaustion

● Red - 30s or less until exhaustion

● Purple - Above MPA


You probably allready know that you can set the parameters of the TTE field?
It’s nothing like ‘real-time’ but, when you go to ride your bike with a preride plan - how you’re going to ride. Maybe you can set the parameters to match your goal watts, so you can then see your TTE of it while you ride…

It’s a great idea but really hard to put into practice. When you have MPA (and the fatigue gauge using Xert EBC if available) you gain a better understanding of what the values mean in terms of how much you have left. Takes a bit of gettng used to but ultimately in the end you gain a better idea of what you can do and how long you can go for.

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