This is an interim report of an on-going study of deaths in 42-km men. The absence of fatal ASCVD in these athletes can not be construed as evidence for the protective role of exercise alone. The ability to run 42 km depends on many factors. Exercise is only one. Avoiding tobacco is another. Dietary factors also play a role. It has not been feasible to remove one of these factors while maintaining the ability to cover the 42 km distance. Some 42-km men claim that megadoses of ascorbic acid protect them from collagen injury. This is supported by animal studies that show increased collagen synthesis proportional to ascorbic acid intake up to dosage levels that would equal 10 grams per day for humans. Their self-selected macrobiotic diet contains a high ratio of peanuts:steak resulting in a high P/S ratio (polyunsaturates/saturates). Dietary manipulation quickly effects their ability to train. Smoking is so rare among these runners that it must be related to specific effects, such as a catalytic agent in tobacco smoke converting linoleic acid into a toxic lipid oxide. Noakes and Opie recently confirmed again (May, 1976) that no cases of "death due to coronary atherosclerosis" have been recorded in marathon finishers. If this holds true for the second 10-year period of this study, then marathon runners will have joined the longshoremen by earning life-long protection against ASCVD. These longshoremen burned 1,876 kcals on the job, equivalent to a 30-km run. Roberts and Straus suggest that many factors can cause atherosclerosis. Only time will tell whether the marathoner is protected from all of them.