Originally Posted by
chaadster
I don't understand what you're saying.
Most everyone's heart rate increases as body temp rises, but that has nothing to do with being indoors or out, only with relative temperature.
What I'm saying is that your heart rate will often rise faster exercising outside in colder air than it would if you were riding under normal temperature conditions. In normal temps, as you gain fitness, your heart rate will both rise and fall more quickly. But in cold temps, it will often take you longer to reach past 100-110 bpm.