These things differ from person to person. Mine's especially slow, which can either mean I need a pacemaker or I have a great heart than doesn't need to work hard to do its job. Could be either. Only a cardiac specialist can give you the appropriate tests, but if you're feeling fine, what's the problem? Because we have tools now to make ourselves nervous wrecks by testing things with a moderate degree of accuracy doesn't mean it's a good idea for our actual lives to do so. None of us is going to live forever, but if it ain't broke, don't fix it.