Not if you’re on the verge of a heart attack. Also slightly more controversially, I think very vigorous/taxing sport (like marathons) could do more harm than good. Like a u shaped distribution where moderate exercise is the sweet spot.
They're probably a net positive on average given the reductions in weight and blood pressure and whatnot, but there's a lot of variability, both in short-term trauma and long-term accumulated damage.
Sports are apparently good for the heart in the medium-long term, but can be very taxing (read: dangerous) for the heart while you're actually doing it.
In the long run, if you increase your intensity slowly, giving time for your body to build up increased fitness it tends to be mostly positive.
But the short-term stress can be fatal if you are already on the verge of a myocardial event.