Some people are so athletic -- running daily in rain, wind and heat in sickness and in health -- that most people wonder if they are masochists. But new research shows that they may just be addicted to exercise.
Stan Jensen, author of Run100s.com, has competed in 20 marathons and 125 ultramarathons in his lifetime. He said he considered each race "fun," but agrees there are sometimes other motivations at work among ultra runners.
"Take the Boston marathon: for a lot of runners that's their...Full Story