The change in my PAI score was quite different to the estimate – is something wrong?

The PAI estimate for Mio PAI Coach workouts assumes you will be running for the workout, so you’ll get more of high-intensity PAI. If your score is quite different, let’s say lower, then you might have been running at a much lower heart rate so got more moderate-intensity PAI. Also, if you do non-programmed activities before the planned workout, the other activities will raise your PAI so the planned workout ends up being worth less than if it was the only activity of the day.