Thought I would post my guided test I did.
Never noticed it existed until I went into the options of the Run app > Training > Lactate Threshold Guided Test.
You need a HRM Strap for this to work.
I started the test, says to warm up for 5-10 mins, I think I went more than I should have going around just under 5min / per km.
At the 10 min mark it was continuing, but I remember reading you have to press the lap button to finish warming up.
Pressed the lap button then gave me a Heart Rate range to keep in for 4 mins.
The screen shows a count down and your heart rate, and I think your average speed.
It will also aleart you if you are under / over or in the ideal range
Then after 4 mins, it then sets a new heart rate range that is higher then before, for another four miniutes.
After this, is the lkast range but for 3 mins, this I remeber for me it wanted me to do over 169 bpm, which I could not do, 166bom was my max.
After this it gives you a new Lactate Threshold rating, and the option to keep on running, which I did.
Previously I had as my Lactate Threshold:
5:14 - 162 bpm
After the test it changed it to
4:51 - 162 bpm
My understanding is this is the recommended pace for a 10km - half marathon and 90% of my max heart rate before my body starts producing lactic acid....
https://connect.garmin.com/modern/activity/1890969843