There are several very interesting studies in the October issue of the ACSM Journal - for those who have even a remote interest in Sports Physiology. (rates of heart attacks during marathons, BDNF production in aerobic vs extreem exercise, ....)
http://journals.lww.com/acsm-msse/pages/currenttoc.aspx
http://journals.lww.com/acsm-msse/pages/currenttoc.aspx