President Trump reportedly believes in the Victorian-era myth that engaging in exercise is unwise and can lead to early death because the human body is like a battery, with a finite amount of energy. The opposite, of course, is true. Being consistently physically active is probably the very best thing we can do to ensure a long and healthy life. And far from draining us of energy, regular exercise gives us more of it. It’s unclear where Trump picked up that particular mistaken belief. But as Minnesota cardiologists Dr. Steven Bradley and Dr. Michael Miedema point out in a recent editorial in JAMA Network Open , the idea that physical exertion is harmful can be traced back (at least) to the ancient Greek legend of Pheidippides , whose long-distance run in 490 BCE inspired the modern marathon. “Some would believe the story of poor Pheidippides is a cautionary tale about the hazards of exercise,” they write, along with their co-author Dr. Erin Michos of Johns Hopkins Univers...