In much the same way, unexpressed anger can give a one-two punch to your energy level. The reason: "We're expending all our energy trying to contain our angry feelings, and that can be exhausting," Baard tells WebMD.

The good news, says Baard, is that we can counter these energy killers by programming more relaxation activities into our day. While for many folks, increasing exercise burns off the chemical effects of stress and anger, others find relief in quiet pursuits: listening to music, reading a steamy romance novel, or even just talking on the phone.

"Whatever is relaxing for you will reduce tension and that will help increase energy," says Baard.

6. Drink More Water and Less Alcohol

You may already know that it's easy to confuse signals of hunger with thirst (we think we need food when we really need water). But did you know that thirst can also masquerade as fatigue?

"Sometimes, even slight dehydration can leave you feeling tired and lethargic," says nutritionist Keith Ayoob, EdD, RD, an associate professor at the Albert Einstein School of Medicine in New York and author of The Uncle Sam Diet.

The solution is simple: a tall, cool glass of water. This is particularly important to boost energy after exercise, when your body is likely to be craving fluids, Ayoob says. Conversely, Heller says, if you find yourself frequently fatigued even after a good night's sleep, try cutting down on alcohol during the evening hours.

'While alcohol initially helps you fall asleep, it also interferes with deep sleep, so you're not getting the rest you think you are -- even if you sleep a full eight hours," she says.

By cutting down on alcohol before bedtime, you'll get a better night's rest, which is bound to result in more energy the next day.

7. Eat More Whole Grains and Less Sugar

The key here is keeping blood sugar balanced so energy is constant.

"When you're eating a sweet food, you get a spike in blood sugar, which gives you an initial burst of energy," Heller says. "But that's followed by a rapid drop in blood sugar, which in turn can leave you feeling very wiped out."