There are many discussions about how to determine your lactic acid threshold outside on the road. Wrong time of year here for that. How do you determine LAT indoors? I have a set of rollers and spin bike at the gym. Please, no running!
I've discovered my sustained HR has increased. i used to be able to ride for a long period at 165. Now I can keep it at 172-174 and not suffer an explosion.
So, suggestions on how to determine LAT indoors?