Should marathon runners take a baby aspirin before a big race?

Probably, according to emerging scientific evidence. But not all doctors agree.

Marathon running can cause muscle injury that triggers production of inflammatory chemicals called cytokines. Cytokines boost activation of blood clotting agents called platelets, potentially raising the risk of clot-induced heart attacks, says Dr. Arthur Siegel, director of internal medicine at McLean Hospital in Belmont and a volunteer in the Boston Marathon medical tent.