Something was up today

When I was out running around as I am apt to do often, I noticed that my HR monitor was telling me that I, even though my pace was quick, my heart rate was low. Strangely low. Not too sure what to make of it. I am guessing a glitch but it did register correctly in the hills later on, so perhaps it was only momentary. Either way, I ran a cold and windy 10km, in a short sleeve, where I should have opted for a long sleeve and gloves. But it was the quickest I have run that distance so I perhaps was moving faster cause I was cold. Regardless, my first km was slow as I warmed up, then I just got faster and stronger. I love that feeling, finishing strong. My quads are feeling the downhills since my run from Thursday but I was pushing them hard. 49:25 ~ 10.1km, 4:53 per km.