Endorphins are endogenous opioid polypeptide compounds. They are produced by the pituitary gland and the hypothalamus in vertebrates during strenuous exercise , excitement, listening to some music and orgasm; and they resemble the opiates in their abilities to produce analgesia and a sense of well-being. Endorphins work as "natural pain killers", whose effects may be enhanced by other medications.
Why the above? Because I'm feeling it. Today I ran the farthest I've ever run on my own accord, my own will, without my high school soccer coach yelling at me to get my a.. in gear. The ipod said 4 miles, amazing. A year ago I would have laughed if you would have told me I would run 4 miles because I wanted to. I do not have a runners body or good running form or talent for that matter. This is pure gut and determination on my part and for that I say..... Ah Yeah. (Plus I can see how you can get addicted to those endorphins, especially in light of my astrological sign- right Mark?) Ha-Ha.