What if it's flat conway? Lifting is the **** it can give you a strong dose of adrenaline just like surfing. I do have to say if your trying to bulk and gain 40 lbs. your surfing is def gonna take a drop, less flexibility and your errors are gonna stick out more, you can readjust your self if your light but when your big your gonna be goin down.
Trust me, once you reach a certain age, if you want to keep surfing on 6-foot-something board you will be doing some kind of resistance/weight training. You can swim or paddle for miles - and you should for cardio - but your body doesn't do "muscle" like it used to. Without other training, and core stuff is fantastic, you start to go backward.
Ditto Bro as you age your body loosing muscle and Its a battle to maintain and gain from the aging process I work out @ a Gym 2 & 3 times a week and Mtn bike too.
I talked to others my age and their routine too to stay in surfing shape. I'm very interested if any others have routines that will help us old guys and gals.