Fuel up. Caffeine boosts alertness, but don’t go overboard with the coffee after an all-nighter—it also causes dehydration and jitteriness. Reach for fruit instead, particularly apples, which have natural sugars your body can use for both instant and longer-term energy. Avoid big meals, though, which will “put you in a food coma.”
Get moving. A quick run “releases a ton of endorphins,” which will make you more alert naturally. Note too that “your brain craves novelty,” so don’t sit still for long and look for fresh ways to engage your senses. “Go smell some smells,” or even spend a few minutes playing some “blood-pumping” video games.
Power nap. This will rejuvenate you only if you keep it brief. Napping longer than 30 minutes produces “sleep inertia” and reduces cognitive function.