Slideshow: 12 Causes of Fatigue and How to Fight It

Not Enough Sleep

Don't overlook the obvious – one of the most common causes of fatigue is getting too little sleep. According to the National Institutes of Health, 70 million Americans may be chronically sleep-deprived. If you're fond of burning the midnight oil, lack of sleep may be causing your fatigue.

Fix: Sleep for seven to eight hours every night.

Sleep Apnea

Some people think they're sleeping enough, but this sneaky condition gets in the way. Sleep apnea briefly stops your breathing many times during the night. Each interruption wakes you up for a moment, although you may not be aware of it. The result: you're sleep-deprived despite spending eight hours in bed.

Fix: Lose weight if you're overweight, quit smoking, and sleep with a CPAP device to help keep airway passages open at night.

Not Enough Fuel

Eating too little is another obvious cause of fatigue, but eating the wrong foods can also be a problem. If you start your day with doughnuts, your blood sugar will spike and crash, leaving you sluggish.

Fix: Always eat a good breakfast. Try to include protein and complex carbs, such as eggs and whole-grain toast. This combination creates sustained energy.

Anemia

Anemia is a leading cause of fatigue in women. It occurs when the body doesn't have enough red blood cells (shown here) to carry enough oxygen to your tissues and organs. Anemia is easily diagnosed with a blood test.

Fix: Treatment for anemia depends on the cause. Common iron deficiency can be fixed by taking iron supplements and eating iron-rich foods, such as lean meat, liver, shellfish, beans, and enriched cereal.

Hypothyroidism

The thyroid is a small gland at the base of your neck. It controls your metabolism, the speed at which your body converts fuel into energy. When the gland is underactive and the metabolism functions too slowly, you may feel sluggish and put on weight.

Fix: If a blood test confirms your thyroid hormones are low, synthetic hormones can bring you up to speed.

Caffeine Overload

While many of us consider coffee a defense against fatigue, it can be a Trojan horse. Caffeine is a stimulant and improves alertness and concentration in moderate doses. But research indicates too much caffeine actually causes fatigue in some people.

Fix: Avoid caffeine as much as possible. This includes coffee, tea, chocolate, soft drinks, and any medications that contain caffeine.

Hidden UTI

If you've ever had a urinary tract infection (UTI), you're probably familiar with the burning pain and sense of urgency. But the infection does not always announce itself with such obvious symptoms. In some cases, fatigue may be the only sign. A urine test can quickly confirm a UTI.

Fix: Antibiotics are the cure for UTI's, and the fatigue will usually vanish within a week.

Diabetes

In people with diabetes, sugar remains in the bloodstream instead of entering the body's cells, where it would be converted into energy. The result is a body that runs out of steam despite having enough to eat. If you have persistent, unexplained fatigue, ask your doctor about being tested for diabetes.

Fix: Treatments for diabetes may include lifestyle changes, insulin therapy, and medications to help the body process sugar.

Heart Disease

When fatigue strikes during everyday activities, such as cleaning the house or weeding the yard, it can be a sign that your heart is no longer up to the job. If you notice it's becoming increasingly difficult to finish tasks that were once easy, talk to your doctor about heart disease.

Fix: Lifestyle changes, medication, and therapeutic procedures can get heart disease under control and restore your energy.

Food Allergies

Some doctors believe hidden food allergies can make you sleepy. If your fatigue intensifies after meals, you could have a mild intolerance to something you're eating – not enough to cause itching or hives, just enough to make you tired.

Fix: Try eliminating foods one at a time to see if your fatigue improves. You can also ask your doctor about a food allergy test.

Chronic Fatigue Syndrome (CFS)

If your fatigue lasts more than six months and is so severe that you can't manage your daily activities, chronic fatigue syndrome is a possibility. CFS can have various symptoms, but the main one is persistent, unexplained exhaustion.

Fix: While there's no quick fix for CFS, patients often benefit from changing their daily schedule, learning better sleep habits, and starting a gentle exercise program.

Fast Fix for Mild Fatigue

If you have mild fatigue that isn't linked to any medical condition, the solution may be exercise. Research suggests healthy but tired adults can get a significant energy boost from a modest workout program. In one study, participants rode a stationary bike for 20 minutes at a mild pace. Doing this just three times a week was enough to fight fatigue.