Marc Bertucco said:

Brendan Rigby said:

Great ride yesterday and not that cold due to the sun, lack of wind, and lack of rain.  We did put the screws into ourselves on the final bits.  The cold does odd things to you: I set a new HR record on that final winding hill in Jersey.  I am told that cold temperatures might make gas exchange (getting oxygen into your blood and out to your muscles) less effective and contribute to an elevated heart rate compared to the same effort in warmer weather.

Another factor that can lead to an elevated HR is dehydration. Blood is mostly water. And on cold days when we don't necessarily "feel" thirsty, because we're not sweating as much easier to forget to drink. Also as nice as it was, our bottles were icing over. So not drinking as much as we should have been. And so with less blood volume to circulate, our hearts will naturally beat faster to compensate.

P.S. Brendan, thinking more about your cold feet. (well, that sounds weird) Did you have one or two layers covering the legs? I'm normally very subject to cold feet, but I think that throwing another pair of bib tights over my fleece shorts and leg warmers, plus the wind vest under my jacket, contributed to better peripheral circulation, so that my normally always numb/cold left foot was pretty much fine all day.