follows a common pattern. In every study, the largest benefit came from just ninety weekly minutes of exercise, yielding an average 20 percent reduction in the risk of dying. After that, the risk of death drops with increasing doses but less steeply. If we assume the studies’ median to be a reasonable guide, to attain another 20 percent reduction in risk beyond the benefits of ninety weekly minutes, we’d have to exercise another five and a half hours for a total of seven hours per week.
