I'm not sure the title is right, but this is the context to my question - I'm new to exercising, I'm doing it purely for heart health. I'm easing myself in. When i go on the bike or cross trainer i both sweat and get breathless - not badly, i could still just about hold a conversation. When I'm on the treadmill however, I walk a fast pace at 6km an hr, i sweat but I'm not breathless - heart rate is up but less than when on the other two. Is this still beneficial? I don't want to run, I'm sure it would make me breathless but i hate the thought of it.