Tired of being tired? Hidden causes of fatigue--and how to fight them.

Randi Rossman battled fatigue for more than 15 years without ever suspecting its cause. "It was bad--there was probably a day or two a week that I just lost, where I could not move out of bed. Then if I actually moved out of bed, I'd have `brain fog,'" says Rossman, 40. Although she had asked doctors about her continual tiredness before, she says she eventually gave up because so many attributed her symptoms to stress or suggested that she seek counseling. "I lived with it for so long, and was told for so long that it was stress or me being crazy, that I didn't let many people know that I was dealing with it," she explains.

By the time her fatigue worsened in her 30s, Rossman had all but given up on successfully fighting it. The turning point came several years ago when she was tested for food allergies and discovered that she is allergic to gluten, a substance found in wheat, oats, barley, and rye. Once she eliminated those foods from her diet, the lingering tiredness disappeared.

Although you may never have suffered from fatigue as severe as Rossman's, all of us have experienced midafternoon slump or weeks when we never feel completely rested. Fatigue is so prevalent among women that more than a quarter listed "persistent fatigue" as their number one health complaint in a recent study. Eighty percent included it in their top 10 health concerns.

Yet fatigue is sometimes misunderstood. It often stems not only from lack of sleep--although sleep deprivation plays a major role--but from a host of physical and emotional factors. Although persistent tiredness can be a symptom of disease, Dr. Mark Moskowitz says the cause is more likely to be lifestyle-related.

"The number of times that you will find causes like anemia, thyroid disease, or depression is relatively unusual," explains Moskowitz, chief of general internal medicine at Boston University School of Medicine. "For most women, there are other factors that are playing a role, including stress, lack of sleep, and juggling too many things at once."

Obviously, an overloaded schedule or day after day of little sleep will leave you feeling exhausted. But there may be other, more hidden factors at work as well. Even if you can't ditch your job or hire a live-in, you can combat fatigue by examining your life for these common causes:

Check Your Plate

Rossman's experience is not uncommon; food allergies can play a bigger role in causing fatigue than most people realize, says Dr. Ronald Hoffman, author of Tired All the Time: How to Regain Your Lost Energy (Poseidon Press, 1993). "Food allergies and intolerances are extraordinarily pervasive," says Hoffman. While most of us don't suffer from obvious, life-threatening allergies, "there are a lot of people who are allergic to common foods such as wheat and dairy products," he says. "By eliminating those foods, they feel lightened up, less sluggish, and less lethargic."

Why? Food reactions cause the release of histamine into the bloodstream. While histamine produces "typical" allergic reactions like sneezing and itchy or burning eyes, it can also cause mood changes and fatigue. People who are sensitive to certain foods can also experience an almost opiate-like effect that also causes tiredness, adds Hoffman. If you suspect you may be sensitive to a certain food, eliminate it from your diet and then reintroduce it over a period of time. Although you may feel irritable the first couple of days without it, you should notice a difference in your energy level by the fourth day if a food sensitivity is part of the problem.

Assess Your Office

Exhausted after a day at work? It may not be your job but your office that's wearing you out. While we can control our living environment at home, at work we may be exposed to a host of airborne substances that can cause fatigue. For example, millions of us are allergic to molds, mites, and pollens, and may experience fatigue, malaise, and depression because of exposure to them while unaware of the cause, says Hoffman.

So-called sick building syndrome is no myth. In a "sick" building, concentrations of potentially harmful chemicals can be many times higher than normal because the air is continually recirculated. Office ventilation ducts laced with mold--because of expense, they may not be cleaned often--and other airborne chemicals from carpeting, office machines, and air and bug sprays also contribute to the problem. If your fatigue worsens at the office, talk to your supervisor about the adequacy of the ventilation in your building or see an allergist to screen for undiagnosed allergies and to explore your treatment options.

Get Regular Exercise

More than 70 percent of people polled last year say they're too tired to exercise. Yet working out, which reduces stress and anxiety (in turn decreasing fatigue) is an effective energy-booster. "Exercise is a great stress reliever," says exercise physiologist Cyndi Ford of the Cooper Institute for Aerobics Research. "Even moderate to somewhat vigorous activity will suffice. You can start with moderate activity such as a 12- to 15-minute walk and build up to 30 minutes a day as you increase strength and endurance."

Aerobic exercise increases the flow of blood to the brain, which makes you feel more alert--and studies suggest that regular exercise may also improve sleep quality, as well as make it easier to drift off.

Check Your Medicine Cabinet

Medication may also be a culprit. "The bottom line is that many medications can have fatigue as a side effect," says Moskowitz, who recently treated a woman who complained of lack of energy. She had recently been prescribed a new blood pressure medication, and when her prescription was changed, her energy levels returned to normal.

Don't rely on the label to determine whether your tiredness is, in fact, drug-related. If fatigue isn't a relatively common side effect, it may not be listed. If you have become more tired since taking prescription or over-the-counter medicine, talk to your doctor or pharmacist about an appropriate substitute.

Get Your Vitamins

If you've been surviving on fast food, you may need to improve your diet. "There are nutritional components to fatigue," says Hoffman, "such as undernutrition vis-a-vis specific nutrients that have an impact on energy, primarily B vitamins and iron."

Shortages of the following nutrients can all contribute to fatigue:

* iron, which delivers oxygen to working muscles;

* vitamins B2, B6, and B12, which all help break down carbohydrate, protein, and fat in the metabolic process to unleash energy;

* vitamin E, which supports a healthy cardiovascular system and is a potent antioxidant;

* magnesium, which helps your body convert food into energy; and

* zinc, which assists in the growth and repair of cells, particularly muscle cells.

A healthy, balanced diet should provide you with the necessary amounts of these vital nutrients, but consider taking a multivitamin to ensure that your body gets what it needs.

Fuel Your Body

Even if you make healthful food choices, you may not be eating enough. "I'd say the second main reason for fatigue in women is underconsumption of calories, which is basically self-imposed starvation," says Kristine Clark, Ph.D., director of sports nutrition at Pennsylvania State University. Frequent dieters may be especially prone to fatigue because their bodies don't have enough fuel to operate at peak efficiency.

The average 140-pound woman should eat about 1,500 to 1,700 calories a day, says Clark; regular exercisers, about 1,800 to 2,000. Consuming significantly less than that will leave you feeling tired--and cranky. If you want to lose weight, limit loss to one to two pounds a week and increase your exercise.

Thinking of boosting your energy with a chocolate bar? Think again. "Sugar has a paradoxical effect on the body," says Hoffman. "It is an energy food and it's good for quick energy, but the flip side of that is a corresponding drop in energy afterward."

Take Minibreaks

OK, you can't drop everything for a much-needed vacation. But you can take breaks during the day that will boost your physical--and mental--energy. "I sometimes need time to clear my head and regroup mentally," admits Florida resident Kimberly Wright, who has two children under 4. "I think sometimes it's more about mental fatigue than physical fatigue because as a mother, I find it's not about just the physical demands of children, but the constant emotional demands. That's what's fatiguing."

Develop your own list of quick pick-me-ups. Retreat to a quiet room and listen to some relaxing music, burn an aromatherapy candle, or focus on your breathing by inhaling and exhaling slowly and deeply for several minutes. When you're harried, even five minutes alone can be transforming.

If fatigue has become your constant companion, take a closer look at your life. Have you been trying to lose weight? taken on additional responsibilities at work? coping with the stress of illness or a death in the family? Understanding why you're suffering from fatigue is the first step in fighting it.

But if you're unable to pinpoint a cause or nothing you do seems to help, talk to your doctor. Life is too short and too precious to squander it being tired!

Medical Causes of Fatigue

Your physician can rule out treatable medical conditions as the cause of your fatigue. Some of the most common medical causes in women include:

* Anemia, which is caused by lack of iron in the blood. This is the primary medical explanation for fatigue in women of childbearing age.

* Thyroid disease, which may affect up to 10 percent of women. Symptoms include fatigue, difficulty losing weight, extremely dry skin and hair, and sensitivity to cold.

* Depression, which is an underdiagnosed, underrecognized condition among women, says Dr. Moskowitz. Fortunately there are now more options available than ever to treat it.

* Chronic fatigue syndrome (CFS). Symptoms include: severe fatigue lasting for more than six months that does not improve with rest, impaired memory and thought processes, pain, and sleep difficulties. Although CFS gets a lot of media attention, according to Dr. Robyn Goshorn of the University of Indiana only about 1 in 375 people has the disease.

Kelly James-Enger writes on health topics from Downers Grove, Illinois.