OK, the first thing to consider is that this study was done with heart-attack survivors. The second thing to know is there are plenty of studies that contradict its findings. What ev, here we go. Researchers at the Lawrence Berkeley National Laboratory and at Hartford Hospital studied the relationship between exercise and cardiovascular disease-related deaths in about 2,400 physically active heart-attack survivors, using the National Walkers’ and Runners’ Health Studies databases. What did they find? A reduction of cardiovascular events of up to 65 percent among people who were running less than 30 miles or walking less than 46 miles per week. Beyond this point, however, the benefit of exercise was lost in what is described as a reverse J-curve pattern.“Results suggest that the benefits of running or walking do not accrue indefinitely and that above some level, perhaps 30 miles per week of running, there is a significant increase in risk,” the researchers write in an Alpha Galileo news release.”Competitive running events also appear to increase the risk of an acute event.” But wait, the same Alpha Galileo report describes a meta-analysis of the mortality of 42,000 top athletes that found that elite athletes (mostly men) live longer than the general population. Yes, more research is needed.