Exercise is important for two reasons. The obvious one is that it oxygenates the blood. The brain runs on oxygenated glucose, carried by hemoglobin in the blood, and a fresh supply of oxygen is good. The nonobvious reason is that our brains, because they were built to navigate in unfamiliar surroundings, don’t do well when they’re not challenged by having to problem solve. Every step you take on a treadmill or elliptical is helping you with the first of these two imperatives—getting your blood oxygenated—but they don’t help your brain to keep its navigational skills and memory systems honed.
...more
