I suggest that you go back to whomever told you that and ask them the source of their information. If they begin with "I heard" smile sweetly and walk away. It is BS!I've been told that hot rounds would cause the cylinder to expand and not return to spec because of the inflexability of the stainless steel.
S&W does advise against the use of +P ammunition in most "J" frame revolvers, including older Model 60s, because the increased recoil accelerates wear on the guts of the gun. The most common maladies are increased end shake and loss of timing.
While I really don't like most +P loads a few now and then won't hurt a thing.