Vishen Lakhiani explains sleep inertia, the grogginess that hits when you wake up. It usually fades in five to ten minutes, but standing outside in sunlight speeds it up. Outdoor light is stronger than indoor light and resets your wakefulness fast.
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Does anyone have a nap and then feel really sleepy afterwards, like groggy? Okay, so this is called sleep inertia, and it's basically due to do with the hormones in your body. There's like melatonin and serotonin, right? And sometimes due to the timing of your nap or how tired you were before you had the nap, sometimes you can wake up and still feel a bit groggy for a few minutes afterwards. This rarely lasts more than five or 10 minutes, and there is a very quick way to switch it off. If you wake up from a nap still feeling groggy, or when you wake up in the morning after sleep feeling groggy. Expose yourself to sunlight. Stand outside, not inside. They found that inside with all the lights on was still not as strong in the amount of lumens, which is the amount of light particles in the air, as standing outside on a cloudy day. So even if it's cloudy, the sunlight still comes through, and that will reset and allow you to wake up after your nap.