Yes -- I know- we all have bad days !! - and nearly always for unknown reasons. I did a 8K easy run on Tuesday - so this morning I did another of the same length but different route. ( pretty much the same starting point) . I wore different shoes. I DID notice that on my walk to the start point, my HR was higher than normal -- perhaps 10BPM higher than normal?? Didn't take much notice of it - thought to myself, maybe I am striding out a bit faster than normal?? But from the start onwards, my calves and achilles complained from the first step -- I got swollen/numb feet on each side ( this has happened before but not commonly) and I seemed to struggle to keep my HR down.
Anyway - I had no option but to finish the run -- it was pretty slow ( not that I am really recording time anymore) - well over an hour for only 8K - but average HR was only 4 beats over Tuesdays run??
Legs are quite tired/sore today - maybe I am doing too much?? Have been travelling quite OK up to today though!! ???? Must measure my resting HR first thing in the morning - IF I can remember!!!