The three requirements for human life are food, drink and fresh air. But their effects on survival have very different timelines. You can live for 30 days or so without food, and you can go for a week or so without drinking water. Your brain, however, is so active that it cannot go without oxygen for more than 5 minutes without risking serious and permanent damage. Toxic electrons over-accumulate because blood can’t deliver enough oxygen sponges.

When you exercise, you increase blood flow across the tissues of your body. The more you exercise, the more tissues you can feed and the more toxic waste you can remove. That’s why exercise improves the performance of most human functions. – Brain Rules