Great, this gives me some insight and a way to apply my VO2max results. I reached AT @ 3:53, HR 85. VO2max was reached over 4 minutes later @8:12, HR 112 so according to this I should exercise for about 4 minutes maintaining a HR below 110? correct? However Im not sure I understand the concept and perhaps someone can help me out. When I took the test and when I performed them as a fitness instructor pre-CFS 20+ years ago I believe the purpose was to get individuals to reach maximum effort and therefore increase the workload so that an anaerobic level was achieved rather early. In that 4 minutes prior to my attaining AT the resistance, or workload (in my latest test, the pace and the incline) was increased within a few minutes. Thus I was FORCED to reach AT and reached it far earlier than I would have if I had maintained a steady, aerobic workload which any endurance athlete knows can go on for long durations. So why would only exercising for 4 minutes be the key when that AT threshold was induced by an increase in the difficulty of the workload? If I maintained a steady slow pace without an increase in workload, theoretically, could I not then work longer w/o achieving AT , while maintaining my HR below 110? Now my experience with ME/CFS and exercise tells me I cant do that, but Im not sure why? But Im also not sure why staying below an INDUCED AT threshold would work either. Am I making any sense?