Sport can help us live longer and keep us mentally fit. Yet only around 14% of Germans get enough exercise. With unforeseeable consequences. On the one hand, fitness freaks go to physical extremes in the conviction that they’re doing their body good. Jogging is especially popular. But marathon runners continue to die of sudden cardiac arrest. Is sport really so healthy? When does exercise become a risk? And why – on the other hand – do most Germans find it difficult to motivate themselves to maintain even a minimum level of fitness? Harald Lesch explores the limitations of sport as a “cure-all”.