I have a similar problem. I was completely sold on the MAF method but had a bad spell of heart rate monitors being erratic and breaking and gave up with them just over a year ago. I spent a year running faster and not bothering with the HR monitor until the last few weeks when I have started suffering from overtraining symptoms (I was ramping up training for an event) I did the test and found out I can’t even run Aerobically anymore! It’s so frustrating. I know I should have known better! If I am walking Aerobically will this ever get me back to running Aerobically? Should I try to run until my heart rate climbs hen walk until it drops or just walk? Thanks