Ok, so I stepped up to 1:30 intervals with 1 minute recovery today - again on the treadmill. The additional 30 seconds turned out to be a bit more challenging than I hoped, but I did finish the set. My lungs are feeling very tight, the inversion has gotten the better part of me, I started feeling tight in my chest after Saturday, I sure hope the air clears soon. I will probably do one more week at 1:30 then try to move to 2 minutes, but I have to feel a bit stronger than I did today. Overall pleased with the progress. | 