How long have you been riding? And if you are new, have you done any aerobic activities in the past? I came from a completely sedentary life and had no aerobic capacity when I first started riding a year ago. It took me a long time to get to the point where I could work out with running out of breath. (I ended up with a diagnosis of exercised induced asthma but it doesn't sound like that's your problem.) So - if you ARE new to riding, maybe you just need to slowly build up your capacity. Let's see what the better informed ladies have to say.