As you can see from my photo, I ride in a sun shirt most of the time. I wear a sport bra underneath, the armpit area is vented and I can roll the sleeves up & down and they snap in place. I am not racing, just riding. Love the breeze as I go downhill. I have several. I also always, always carry a bandana, When it is hot I get it soaking wet and tie it around my neck to help me keep cool. Stopping, taking off your helmet and soaking your head is excellent as well.