It could just be because I didn't have the energy for a proper walk today - a mere three and a half miles, all of it along roads to avoid mud and nettles. Also no training obviously. Yesterday afternoon following my 8 mile walk I was so tired I ended up taking an unplanned nap - and in the process proved the theory that napping in the afternoon affects sleep that night. I was awake for hours, and not very happy by morning though at least most of the nettle stings had stopped burning and itching - unless I scratched my arm or ran water over any part of the affected areas. Hopefully I'll sleep better tonight and have more energy tomorrow.