There is a very good article on the Running Times site on running high mileage and sickness. Every runner should read this.
Norm Klein was worried—worried about the health of some of the athletes he and his wife Helen had come to know as friends and fellow competitors during Norm’s 14-year tenure as race director of the Western States 100. “It was after I was no longer race director, in 2000, that I started observing what I believed was a cancer trend in runners who had competed over the years in the event,” Klein says. The 20 athletes he refers to are or were all residents of northern or central California and northern Nevada; 15 men and five women, two of whom are now deceased.
Link.
