One of the greatest dangers in growing old, apart from arthritis, high blood pressure and impotence, is forgetting how to laugh.

“Ha, Ha!” you say. (Or maybe you don’t.)

Did you know that the average four-year-old laughs 300 times a day while the average 40-year-old laughs only four?

So says a blog called “Aging Healthily, Happily, and Youthfully,” whose author somehow managed to corral a bunch of four-year-olds and count their giggles.

But seriously — which is what we don’t want to be, right? — laughter is great for the bones, great for your social life, great for your marriage, and burns up a lot of calories. (Okay, I made that last part up.)

In the interest of not becoming a crabby old man, I’m determined to stop taking myself so seriously, crack more jokes, listen to more jokes, and make zany videos like the one below, which is premised on the idea that just hearing people laugh can be therapeutic.

Perhaps among the zillion and one sounds in our galaxy, laughter is the most beautiful. Listen!

FRIDAY POSTSCRIPT: Check with your doctor to see if you have grumpitis, seriousis of the liver or CSS (Codgers Sourpuss Syndrome). If you do, I recommend you hang out with some four-year-olds and give comedian Fred Klett a try: https://www.youtube.com/watch?v=PbDOfhUe_EM