Riches and celebrity, another dimension of our dopamine economy, contribute to the addictive potential of these extreme sports. “Overtraining syndrome” is a well-described but poorly understood condition among endurance athletes who train so much that they reach a point where exercise no longer produces the endorphins that were once so plentiful. Instead, exercise leaves them feeling depleted and dysphoric, as if their reward balance has maxed out and stopped working, similar to what we saw with my patient Chris and opioids.
