I completely understand where you are coming from, being a runner myself. Great description.

What brutal and idiotic sentimentalism! You disgust me!

Kidding.

Pretty short for an essay and bordering a little on being poetry.

It may just be me, but I can't seem to get the same picture you are getting after your torturous but fulfilling run on the beach to the serene scene of the waves crashing. You should try to describe the scene a bit more.

Otherwise, short and sweet.