Why do soem people's faces blush after strenous exercise?

i've noticed a couple of new girls in my spinning class get all blushed after a hard intensity workout? What's the reason they get blushed as opposed to the ';senior'; riders? Does it have to do with fitness level?Why do soem people's faces blush after strenous exercise?
It's all just a matter of our bodies %26amp; hearts and how they react to exercise. Sometimes it has to do with fitness level, like you said. For example - the ';senior'; riders have been spinning for a while so their heart doesn't ';think'; it's as hard as some of the begginers. Other times, it's just a coincidence.... I've been exercising for years and my face turns a bright red when I do cardio. It's like how some people get embarassed and their faces turn red and some people don't blush at all.