I am new to using HR monitoring during my runs (could never stand using the strap because of chafing) although I am a fairly seasoned long distance runner. I have been using my 235 for about a month now and have collected enough HR data to sort of determine my zones. Some of the data is a bit junky, and I still have some runs where the HR either plummets or spikes on a flat terrain going at a steady state. However, I can sort of get a general idea of where I stand.
The trouble is that the zones are telling me that I'm running all in zones 4 and 5. There's surely no way I could do this without passing out given that I run 60-70 miles a week (and have for more than two months). I have therefore adjusted the zones so that they will fall more in line with most miles being in zones 2 and 3, with a few in zone 4.
So, to my question - can I apply these new zones to runs I have already completed, either all at once, or on a run-by-run basis? I'd like to see how the percentages would have come out in terms of each zone.
Thanks.
