I managed to run the 6r3 on Monday (thanks for the plaudits), but am worried about the next. I use a Polar HR monitor and on the aforementioned run my HR went from 100 after the walk to 174 max. running. The thing is that it was almost a straight line from those two points and I wonder what it will be on the next run. I run on a treadmill and use 9.6 km/hr as my run speed and 1.5 degrees slope. I could drop one or both of these, but it will feel like a defeat.
Of course slightly defeated is better than permantly dead!