To swiftly replenish energy after sleeping for fewer than eight hours:
Take 20 to 30 minute power naps.
Drink plenty of water throughout the day.
Try some light exercise to give yourself a quick energy boost.
Take little to moderate doses of caffeine.
Take some time to enjoy the sunshine.
Eat little, healthful snacks that are high in complex carbohydrates and protein.
Apply a cold water splash to your face to help you wake up.
For general wellbeing, however, give regular, high-quality sleep first priority.