l mean good enough to replace daily running?

It is an excellent form of cardiovascular exercise & overall exercise. Take a look at the surfers that surf quite often (not the once a week types) & look at their physique. You will notice two things: First, they look younger than their age. Second, they will have excellent physiques that exercise machine commercials try to attain. Most of the people in those TV commercials really have surfer type bodies & not the other way around.

Paddling, if u have ever tried surfing, requires a lot of conditioning like long distance running with one major difference..surfing BUILDS & TONES ur muscles.

yes! its excellent, the paddling...surfing works your whole body out, tones it from head to toe..

Oh yes and a lot more fun. Excellent all around. Swimming paddling and hopping up builds every muscle and if you are lucky enough to surf in places like myself in S.Cal. Just about every beach l surf at has lots of stairs. Just carrying the board up and down a few dozen times a week keeps you in tip top shape.