If you have the opportunity for a power nap, particularly after a poor night of sleep, by all means, take one. You will feel more alert and energetic afterwards, and once rested after your mid-afternoon nap, your mood, efficiency, and alertness level will improve greatly. Scientists have even proven that taking a 20-minute nap approximately eight hours after you have awaken will do more for your stamina than sleeping another 20 minutes in the morning. Of course when you first come out of your afternoon nap, you will feel a bit groggy for around ten minutes, but once your decline in motor dexterity dissipates, you will reap the rewards of being well rested and ready to go for the rest of the day.