Go to Apps -> Settings -> Application Manager -> Swipe until you get ALL (DOWNLOADED is the default, at the top) -> Scroll down until you see S Health-> Tap on it -> Select FORCE STOP (the DISBALE button is possibley "greyed out" -> Exit Application manager
Do the above again. This time you must see the DISABLE button "not greyed out", Tap on the button and S health is disabled. Uncheck the "receive notification" check box. You are done!