So exercise sharpens aside
Page 205. So exercise sharpens aside. But how much do you have to sharpen it? Do you have to run? Get breathless and sweaty? The great news is that there’s a lot of evidence that you can do most of the intellectual benefits of exercise with just 20 to 30 minutes of moderate aerobic activities.
— from Fuel (Energy)
In the book
Then the steps, one tank at a time. Refuel the physical tank first, because it carries the others. Move your body — exercise is the fastest way to alter a depleted state and sharpen the mind; when the gauge spikes into panic, take four or five long, slow belly breaths, which calm the whole system at the source; and never undervalue sleep and food, the plainest refuelers there are. Spend the mental tank on purpose. Attention is the single most essential mental resource you have — it decides what you even notice, and your brain processes everything at a real cost, so automate the small, repeated decisions to save the fuel for the ones that matter. — Fuel (Energy)