Hearty Laughter

Is is hearty or hardy? I know they are both adjectives. The are synonyms as well as homonyms. They both mean robust.

So when I say hardy belly laughter is an aerobic exercise, should I say Hearty instead?

I guess I could use either one since they are synonymous, yet I will choose Hearty, because hearty laughter is good for the heart. Hearty has a few other meanings, too, which make it a bit more complex, because it also means exuberant.

I wish you a Happy Father's Day and a hardy heart!