I find it really unnerving and feel like there's something wrong with me and I must be dreadfully unfit. That sucking in air feeling. Usually when walking up a big hill, I do a mile uphill in 18 mins. But I always think I sound terrible. Do you get used to this sort of breathing? Does it bother you?
(when I'm not active, my breathing is really really quiet, almost unnoticeable, very different to when I exercise, a big contrast.)
being breathless is not a bad thing.....the important thing is how long it takes you to get your breath back after you have finished that particular exercise as that is they key to your fitness...the fitter you get the quicker your heart rate/breathing will come back to normal.