The Reason that we tired

Even if you manage to get to bed at a decent hour most nights, we’re willing to wager that you’re exhausted. Women complain about feeling tired nearly four times as often as men. But if your fatigue is so crippling that it makes it hard to care for your family, do your job, or enjoy your social life—and lasts for several weeks—don’t just blame the draining demands of modern life.

Fatigue can be a symptom of everything from the mundane to the life-threatening, says Neil Shulman, MD, associate professor in the department of medicine at Emory University Medical School and co-author of Your Body’s Red Light Warning Signals. And, while figuring out what’s wrong can be challenging, experts insist that many of the reasons for exhaustion are easy to fix. Talk to your doctor about the following possibilities.

No-need-for-alarm reasons you’re tired:You’re low on Vitamin B12 The nutrient is an energy booster that maintains healthy nerve cells and oxygen-transporting red blood cells. If you’re low, you may feel draggy. You might also suffer from constipation or diarrhea, says women’s-health expert Sandra Fryhofer, MD, past president of the American College of Physicians-American Society of Internal Medicine. If left unchecked, a deficit can lead to numbness and tingling in the hands and feet, difficulty with balance, poor memory, and confusion.

What to do: A B12 blood test (your doc can do the test in the office by taking blood from your arm) will reveal your level. B12 comes mainly from animal sources, so make sure your diet includes dairy, eggs, meat, or fish. Vegans can opt for fortified veggie burgers or soy milk. B12 does come in supplement form, but it’s not easily absorbed. Your doc might recommend an injection.

Drugs are sapping your energySide effects from prescription and over-the-counter medicines like antihistamines can secretly sap your energy. Each person reacts to allergy meds differently, and some might make you drowsy even if they’re touted as non-drowsy formulas. Many beta-blockers for hypertension are also known for causing fatigue, and certain antidepressants have the same effect.

What to do: Medicine fatigue isn’t something you always have to live with. New or different formulations may not have the same effects, so check with your doctor about switching brands, dosages, or treatments. Keep an eye on labels, too: If insomnia is listed as a side effect, don’t ignore that warning.

You have a vitamin D deficitToday’s healthy desire to avoid sun dam­age has created an epidemic of D deficiency, says Annabelle Volgman, MD, a cardiologist and medical director of the Heart Center for Women at Rush University Medical Center in Chicago. In fact, many of her female patients complaining of fatigue and chest pain are low in D, which the body makes from exposure to sunshine. The cause of the D-deficiency-and-fatigue connection isn’t clear, but low levels of this vitamin are associated with increased risks of heart disease, high blood pressure, some cancers, and neurological disorders.

What to do: A “25-hydroxy vitamin D” test of your blood (taken from a vein at the doc’s office) can check your levels; normal is about 16 to 74 nanograms per milliliter. Although you can find vitamin D in fish, eggs, and cod liver oil, Dr. Volgman says, most women who are deficient can benefit from supplements. To beat fatigue, she recommends 10 minutes of sunshine per day. A multivitamin can deliver 800 IU, twice the recommended daily amount.

Surprising disorders that can cause fatigueYour thyroid’s out of whackIf you can’t lose weight or have unexplained weight gain, drier skin than usual, a slowed heart rate, a change in your periods, or a feeling of being cold—along with fatigue—you may have hypothyroidism, says Francine Kaufman, MD, head of the Center for Endocrinology, Diabetes, and Metabolism at Childrens Hospital Los Angeles. Hypothyroidism occurs when the thyroid gland, located in your neck, doesn’t produce enough metabolism-regulating hormones. If it progresses without treatment, the disorder can cause constipation, infertility, joint pain, and heart disease. Eight out of 10 thyroid disease patients are women, and about 5% of women in their child-bearing years are thought to suffer from hypothyroidism, although some experts think the numbers are much higher.

What to do: Check into your family history, an important risk factor, to find out if anyone else has a thyroid imbalance. Your physician will order a thyroid-stimulating hormone (TSH) blood test. If it’s positive, you’ll probably need thyroid-hormone-replacement therapy for the rest of your life. Good news: It usually works great.

You’re depressed“Fatigue is one of the most common signs of major depression,” says David Mischoulon, MD, PhD, a staff psychiatrist at Massachusetts General Hospital and assistant professor at Harvard Medical School. About 12 million adults (more women than men) suffer from depression—and the lifetime risk for women is about 20%.

What to do: You may think everything’s fine, but coming clean about feeling stressed, anxious, or sad can reveal a problem. Therapy and antidepressants (despite the possible fatigue side effects) are proven solutions, and getting more exercise may help, too.

You have celiac diseaseRoughly 1 in 133 Americans suffers from this digestive condition, a destructive reaction in the small intestine to gluten, a protein in wheat, rye, and barley. When you eat regular pizza or cookies, for instance, you may experience bloating, pain, diarrhea, joint discomfort—and extreme fatigue—because the disease starves the body of basic nutrients, says Marianne Frieri, MD, PhD, Chief of Allergy Immunology at Nassau University Medical Center in New York.

What to do: If wheat-based foods seem to make you sick and tired, you’ll need a series of blood tests. Depending on the results, the doc will do an endoscopy (a small intestinal biopsy). If celiac is confirmed, you’ll need to overhaul your diet. The good news: Gluten-free eating—making creative substitutions for wheat flour—is getting easier. By some estimates the number of gluten-free foods on grocery shelves is growing annually by nearly 25%. For help, read The G-Free Diet: A Gluten-Free Survival Guide ($24.99; Center Street, 2009) by Elisabeth Hasselbeck, co-host of The View.

Scary problems you can’t ignore:You have heart diseaseWomen having heart attacks often feel fatigued. “According to a recent study, 70% of women say they had a sudden unusual sense of tiredness beforehand,” Dr. Volgman says. Doctors typically chalk up women’s heart symptoms to unrelated causes (like stress) and may miss the diagnosis of the three most common problems: heart attack, congestive heart failure, and diseased valves. Yet, in the past 25 years more women than men have died of heart disease each year.

What to do: Brush up on the lesser-known heart attack warning signs, like heartburn and loss of appetite. Your doctor may do an electrocardiogram (EKG). If that’s normal, she may do an echocardiogram, or ultrasound test of the heart’s muscle walls. Diet and exercise changes can lower your risks—and energize you.

You’re diabeticThis debilitating disease can tire you out in two ways. When blood sugar is high, glucose (i.e., energy) is literally being flushed out of the body and into the toilet, says Sue McLaughlin, RD, president of health care and education for the American Diabetes Association. The body’s cells are being starved of the energy they need to keep running. And the other problem is increased thirst, as your body (in its attempt to dilute the high sugar in the blood) prompts you to drink more. The result is many nighttime trips to the bathroom and interrupted sleep.

Nearly 12 million American women have diabetes, and another 29 million are thought to have prediabetes, or high blood sugar that isn’t quite high enough to qualify as diabetes but is plenty high enough to cause fatigue. Diabetes can quadruple heart disease risks, which explains why more than 65% of people with diabetes die of heart disease or stroke.

What to do: Your doctor will likely do a fasting-blood-glucose test. If you have diabetes, you’ll probably need to check your glucose regularly and control it with diet and exercise, oral medications, and possibly insulin. If you have prediabetes, studies show that losing weight and getting more exercise can prevent or delay the full-blown disease.