There’s a cloud of mystery around the algorithms. Suunto is not telling anything except this clause in their online documentation that VO2max estimate will appear after any run or walk longer that 15 mins. Later on when you do more exercises the number should get more accurate.
Previously they were using FirstBeat algorithm and it was a known fact that hiking or trekking was not optimal for the calculation, the result would be more reliable on flat terrain. Many people were criticising why VO2maz was enabled for trekking at all.
Now that we got the update we know even less. I am not aware if it is available for trekking at all.
My own experiences are just awful. Before this week’s update I had a crash and my watch lost completely VO2max estimate. Now it is not appearing anymore no matter what I do. I’ve done flat terrain runs and forest walks, long ones and short ones and VO2max just fails to appear. I am planning on doing a factory reset next.