We've all been there: sitting at your desk at 10 a.m. and wishing you'd gotten more sleep the night before, or feeling at 4 p.m. like you'll need a gallon of coffee to get through the rest of the day.

While nothing beats getting enough sleep at night, there are plenty of easy ways to get an instant energy fix—beyond slurping cup after cup of coffee. Next time you feel the daytime drowsies coming on, try one of these options.

Guzzle some water. Staying hydrated is one of the most basic ways to stay focused and engaged, and there's a good chance that the tiredness you're feeling is a result of too little H2O. A recent study of athletes found that when they limited fluids and water-rich foods for 15 hours, 92 percent of them felt fatigued; they also reported memory lapses and difficulty concentrating. Down a glass, and continue drinking every hour or two.

Turn on some tunes. Listening to your favorite music can help pump you up and keep you going. Researchers have found that people who listen to music on headphones while working at their desks are 10 percent more productive than those who don't.

Sneak a kidlike snack. Believe it or not, a banana and peanut butter sandwich could be the perfect energy boost. Bananas pack potassium, a mineral your body needs to convert sugar in your blood into energy. Aim for 320 mg of magnesium and 4,700 mg of potassium daily. Other good sources of potassium and magnesium: fruits, vegetables, beans, and nuts.

Sip the old favorites. Coffee and tea still serve a purpose in keeping us awake, just maybe not in the way you've been using then. Rather than running to the nearest café for a jumbo caffeine concoction, order a black tea. Its amino acids, combined with caffeine, improve alertness, memory, and reaction time—and may reduce stress. Can't abandon coffee? Get a small cup and finish it gradually. Putting mini servings of caffeine into your bloodstream keeps you awake and alert more effectively than chugging a giant joe.

Use Mother Nature. Long used in Asia, Siberian ginseng (Eleutherococcus senticosus, to get technical) has been found to increase animals' ability to work and also to increase human stamina. In fact, Russian cosmonauts used it on the job to counter the fatigue associated with long hours and lack of sleep. Completely appropriate for those days you feel like your life is a giant spacecraft you need to manage. But that's every day, right?