A school in Illinois made students exercise before class and accidentally discovered one of the most powerful learning drugs on earth. They made the kids run. The school was Naperville Central High School. Every morning, students would show up before their first class, put on heart rate monitors, and exercise hard enough to push their heart rates into a specific zone. Then they went straight to class. The results caught the attention of a Harvard psychiatrist named John Ratey. Because something strange was happening to these kids. They weren't just getting fitter. They were becoming better students. When Naperville students later took TIMSS, an international test used to compare math and science performance across countries, they scored among the highest in the world. Ratey spent years studying why. And the answer completely changed how I think about exercise. When you exercise, your brain releases a protein called BDNF. Ratey calls it "Miracle-Gro for the brain." It helps brain cells grow, strengthens the connections between them, and makes it easier for your brain to absorb new information. Exercise also increases dopamine, serotonin, and norepinephrine. The exact chemicals your brain uses for attention, motivation, and learning. Which means those students weren't exercising instead of learning. They were exercising so their brains could learn. I think most of us have this completely backwards. We treat exercise as the thing we do when the important work is finished like: > I'll work out after I study. > After I write. > After I finish this project. > After I get through my inbox. And when life gets busy, exercise is the first thing we remove because it feels like we're buying ourselves another hour. But Ratey's work suggests you're making a terrible trade. You're gaining an hour of time while making the brain that has to use those hours worse at learning. I've started thinking about exercise less like fitness and more like preparation. If I have something difficult to learn, write, or solve, movement shouldn't come after it. It should come before it. You're probably not too busy to exercise. You're too busy to learn slowly.