For the estimated one in every thousand to five thousand people living with arrhythmogenic cardiomyopathy, the question of how to inhabit a body that resists exertion has long carried mortal weight. A Johns Hopkins study published this week offers a meaningful distinction: while high-intensity aerobic exercise raises the risk of dangerous cardiac events by 58 percent in this population, strength training appears to carry no such burden. The finding does not dissolve the constraint these patients live under, but it refines it — inviting medicine to move from broad prohibition toward the more hu