Sure, everyone feels tired now and then. But are your energy stores secretly zapped? To run on sustainable energy, ask yourself this:

When is the first time that you feel tired during the day?

a. When I awaken, even after sleeping a full 8 hours every night for a week
b. Morning, or at the latest by midafternoon
c. Whenever I move
d. Whenever I have to deal with my boss
e. Not until after a day of working 12 hours or more

Results: If you answered anything other than e., it could be a sign that your energy systems are slightly (or completely) out of whack, causing you to feel tired when you should feel energized. First, make sure you're doing the basics for energy: Maintain good sleep habits, keep up your daily walks, and don't fill up on sugar and saturated fat.

Still zapped? Consider adding these energy boosters:

• DHA -- This is the active form of good omega-3 fats, and it helps keep the nerves firing to your muscles. Get it from either fish oil (2 grams daily) or a DHA supplement (600 milligrams daily).
• Ribose -- This is a sugar your body makes naturally, and it helps build the energy blocks of your body. It's not found in food, but you can get extra in supplement form. It's not right for everyone, but if your doctor gives you the green light, you could try 500 milligrams three times a day for a week, then move up to 5 grams three times a day for 3 weeks to get a sense of the effect.