Originally Posted by
Iride01
That's not true. The body burns fat during all exercise and even just sitting in your chair. It just can't burn it fast enough above a certain level of effort. So the energy needed is supplemented by glycogen and serum glucose.
Read my post again while keeping in mind that one of the definitions of zone 2 is that you are burning MORE fats than sugars... which is not true anymore above zone 2. My post remains true during the 20-30 minutes adaptation time you are still burning more sugar than fats despite a lower HR and power.
So the point is that if you'd do 10 minutes HIT then 20 minutes "zone 2", then repeat this pattern, you would never be in zone 2, despite the fact that most apps would tell you 2/3 zone 2, 1/3 higher zones.