Definition of light cardio: Pointless boring, non effective exercise best reserved for old ladies.
If you want to walk, walk. Just don't call it exercise. If you want to jog, jog to the bus stop. If you want ride a bike, get on a bike and go somewhere. If you want to elevate your heart rate, bang your girlfriend. If you want to build muscle and burn fat, lift weights.
so you wouldnt consider speed walking/steady jog at 4.0 uphill effective? I agree that a girl walking around the track and calling it cardio is stupid since they dont even break out in a sweat (unless it's 100 degrees), but if it elevates your heart rate then it's cardio nontheless and it is doing something.