Can you calculate % of V02 max at which you're working (assuming it's >100%) by measuring change in blood oxygenation with a pulse ox?
My understanding is that working at >100% VO2 max means you're not absorbing enough oxygen to fully re-oxygenate your arterial blood (ie going hypoxic, which, I believe, is what a pulse ox is often used to detect). It would seem, then, that by measuring the rate at which your blood oxygen level is decreasing, that "oxygen deficit" could be quantified.
Am I missing something? Would this actually be feasible? (I don't have any sense of how much blood oxygenation level would change and how sensitive/accurate the readings are from a pulse ox)
What first got me curious about this question was trying to experiment with the original Tabata HIIT regimen (the "IE1 protocol": 8 intervals of 20s at 170% VO2 max, followed by 10s of rest). I realize that actually paying attention to readings during the exercise is likely unfeasible, but was wondering if looking at pulse ox data after the fact could give a sense of whether the intensity goals were met.