A 10-minute power nap quickly refreshes your brain without making you groggy. In that short window your body shifts into light sleep, which restores alertness, sharpens focus, boosts mood, and improves memory without entering deep sleep (which can cause sleep inertia). 

Playing white noise during the nap masks sudden sounds and keeps your environment steady, so your brain relaxes faster and stays undisturbed, letting you get the full benefit of the nap in less time.