Forum Moderators: phranque
"acceptable" is a relative term.
I do it on at least 2 webpages, linking all or part of the heading to another internal page. Been this way for over 2 years, no penalty from any SE AFAIK. It also validates with action tag outside header tag. Control appearance with external CSS. As long as it displays as an <H> tag and isn't deceptive, I see no reason not to - others may disagree.