12 Reasons You're So Tired—and How to Get Back on Top

When people ask you how you are, how do you respond? Do you say you're fine—or tired?

If you were too exhausted even to answer the question, you're not alone: Fatigue is endemic these days. Here are a dozen potential reasons behind that run-down feeling and how you can re-energize yourself.

1. You're bored.

Boredom happens when parts of your life have created a rut of routine, says clinical psychologist Judith Sills, Ph.D. "There's not enough zap in your brain," she says. Sills, author of The Comfort Trap (Viking, 2004), concedes that humans are creatures of habit, so routines are essential for life. But comforting routines and habits can become deadening. That's when lack of zing can translate into fatigue. There's a loss of energy when you have nothing to stimulate you, she says.

The fix: Do something new, Sills suggests. Even small changes, such as a two-day getaway, can be life-affirming. "There's a clear link between our emotions and the anticipation of satisfaction and physical energy," she says. Changing your routine also helps. Try driving down a different road or eating food you haven't tried before. "When you take in new information, your spirit feels a sense of possibility," says Sills. "It's mind food."

12 Reasons You're So Tired—and How to Get Back on Top

2. You have allergies.

Think of allergies as the body's way of fighting unwanted guests. The trouble starts when allergens, such as pollen, certain foods, or animal dander invade the mucous membranes of the eyes and throat, says Lily Pien, M.D., an allergist at The Cleveland Clinic. This triggers the body's antibodies to fight the invaders, causing a release of histamines. The body's reaction to the allergens is often excessive, leading to sneezing, shortness of breath or itching. "It's these reactions that wear you down, especially when they keep you from sleeping." she says.

The fix: "Don't misdiagnose yourself," says Pien, "Most people are allergic to more than one substance." She advises seeing an allergist and getting a skin test to determine the allergens that may be affecting you. Antihistamines and nasal steroid sprays are both typical treatments, she says, and adds that 20 percent of the U.S. population suffers from allergies.

12 Reasons You're So Tired—and How to Get Back on Top

3. You're over-caffeinated.

It seems like a contradiction, but caffeine, a stimulant to the central nervous system, can actually make you tired, says Cheryl Forberg, a registered dietician and the author of Positively Ageless: a 28-Day Plan for a Younger, Slimmer, Sexier You (Rodale Books, 2008). A once-a-day dose in the morning in tea or coffee is fine, she says. But people can create a vicious cycle when they keep ingesting more caffeine to counteract the exhaustion they feel after the previous dose wears off. And, she adds, the cumulative effects of the day's caffeine—such as increased heart rate and a rise in blood pressure—can also keep you from getting a good night's sleep.

The fix: Consider antioxidant-rich green tea, says Forberg. A cup of green tea contains 50 mg of caffeine, compared to coffee's 137 mg and black tea's 65 mg. Not eating or drinking high-caffeine foods and drink—including dark chocolate and certain soft drinks—from late afternoon on is also a step towards restful sleep. Keeping caffeine to a minimum is the best way to go, she says.

12 Reasons You're So Tired—and How to Get Back on Top

4. You're multi-tasking.

Doing one thing at a time is a luxury for most people. But multi-tasking has its downside. "When you multi-task, you need to switch back and forth from one project to another and monitor all the projects simultaneously," says Neal Roese, Ph.D., a professor of psychology at The University of Illinois at Urbana-Champaign. Multi-tasking is a big drain on glucose, which fuels everything the brain does, he says. Not surprisingly, studies show that too much flitting from one task to another ultimately leads to errors and fatigue. Ingesting sugar may keep you going temporarily, but eventually you crash.

The fix: The trick, says Roese, is to keep your projects down to a minimum; he suggests no more than three at a time. Prioritizing your projects and taking the short frequent breaks that allow glucose levels to be restored are also useful strategies.

12 Reasons You're So Tired—and How to Get Back on Top

5. You're anemic.

People with anemia typically don't have enough red blood cells in their body. And, because these blood cells are the body's transportation system for oxygen, fewer of these cells mean less oxygen makes its way to the cells—including that of the brain. "People whose cells get less oxygen may be less able to concentrate and they may feel less energetic, says Alan Greene, M.D., clinical professor of pediatrics at Stanford University and the author of Raising Baby Green (Jossey-Bass, 2007). The most typical type is iron-deficiency anemia, but loss of blood cells through internal bleeding can also be a cause. He says anemia is especially harmful to children, who need the oxygen to fuel their developing bodies and brains.

The fix: Greene advises taking a blood test. On a complete blood count (CBC) test, a low hematocrit indicates anemia (hematocrit measures what proportion of blood volume is made up of red blood cells). Testing serum ferritin, a measure of the body's iron stores, can detect iron deficiency, which can cause symptoms even before full-blown anemia develops. Eating iron-rich foods like lean meat, poultry and beans can help increase the supply, especially when accompanied by foods high in vitamin C. Greene also suggests women and children take supplements that contain iron. Men should speak with their physicians first before taking iron supplements, as their bodies don't easily excrete any excess, and too much of the mineral can also be a cause of fatigue.

12 Reasons You're So Tired—and How to Get Back on Top

6. You have poor posture.

Standing up straight looks impressive and, it turns out, has health benefits. If you hunch your shoulders forward, don't equally distribute your weight on both feet, or create an inward curve in your lower back, you're setting yourself up for fatigue, says Kathleen Koch, an exercise physiologist at The Cleveland Clinic. That's because it's harder for blood to nourish muscles that are being held in inefficient positions typical of bad posture. "Reduced blood flow means your heart and lungs have to work harder, and this makes you tired," she says. Sitting improperly and even running with poor form has the same effect.

The fix: Koch suggests strength and core training to address poor posture. For example, she says to correct slouched shoulders—a sign that the chest muscles are disproportionately stronger—you need to strengthen the muscles in the upper back. Because poor posture is a good indicator of muscle imbalance, it's important to train all muscle groups equally, she says.

12 Reasons You're So Tired—and How to Get Back on Top

7. You have an underactive thyroid.

One of the top medical reasons for a slow metabolism and low energy is hypothyroidism, says Nunilo Rubio Jr., M.D., assistant professor of endocrinology at The University of Texas Medical School at Houston. Women are more predisposed to the condition, which is from the thyroid gland's secreting less of its hormones. This, in turn, causes fatigue, as well as weight gain, intolerance to cold, and dry hair and skin. Rubio calls it the "turtle effect." Unfortunately, in most cases, it's the body's own autoimmune response that's to blame. The antibodies involved gradually can damage and, in some cases, destroy the thyroid, a condition known as Hashimoto's thyroiditis. In severe cases, says Rubio, metabolism slows down so dramatically that the patient usually requires an intravenously administered dose of thyroid hormones.

The fix: Rubio suggests those suffering from fatigue ask their physician for a blood workup to determine the level of thyroid- hormone activity. If you're diagnosed as having hypothyroidism, a doctor will typically start thyroid-hormone replacement therapy. Once thyroid-hormone levels are restored, energy usually returns to previous levels. (Although iodine deficiency is often linked to hypothyroidism, most people in the U.S. get adequate amounts by using iodized salt and eating iodine-containing food.)

12 Reasons You're So Tired—and How to Get Back on Top

8. You have undiagnosed heart disease.

A heart that's unable to pump blood efficiently has to work harder to transport oxygen throughout the body. Fatigue is the result, says Nieca Goldberg, M.D., cardiologist and author of Dr. Nieca Goldberg's Complete Guide to Women's Health (Ballantine Books, 2008). Several conditions can cause the heart to overexert itself, including clogged arteries, high blood pressure and heart-valve problems. Typically, fatigue due to undiagnosed cardiovascular condition manifests after exertion.

The fix: If you've ruled out anemia, hypothyroidism and infection, and you still feel tired, it's important to get diagnosed for potential heart problems, says Goldberg. Tests typically include an echocardiogram to see how the blood is pumped through the heart, and a stress test to reveal arterial blockages. Not pinpointing heart disease as early as possible can mean more severe symptoms over time, such as shortness of breath and fluid build-up.

12 Reasons You're So Tired—and How to Get Back on Top

9. You're not exercising enough.

It seems counterintuitive that doing nothing can make you fatigued, but it's true. "If you move, you'll feel less tired," says Dr. Koch of The Cleveland Clinic. When you're sedentary, she says, your metabolic rate decreases and you burn fewer calories, so you feel exhausted. Exercise gets that metabolic rate up, which means more energy, and not only the physical kind. People who say they're tired are often depressed, says Koch. Exercise increases the production of dopamine, a hormone that's a mood enhancer.

The fix: Literally, start with small steps. Koch says that research confirms that even a 10- to 15- minute daily walk provides cardiovascular health benefits But, she advises, don't forget to include strength training in the mix, which helps build lean muscle mass. Overall, increasing your amount of weekly exercise means you'll be able to burn even more calories, she says. And that means even more energy at your disposal.

12 Reasons You're So Tired—and How to Get Back on Top

10. You're dehydrated.

At least half of our bodies and 92 percent of our blood consist of water. "Water serves as a medium for the body to perform its life-sustaining functions, such as regulating body temperature and eliminating waste," says Toby Amidor, a registered dietician in New York City. "If you don't ingest enough water to help these metabolic reactions occur, you'll become tired or lightheaded."

The fix: At the first sign of thirst or dizziness, all you need is a small amount of liquid, as little as half a cup or water or fruit juice, says Amidor. Although many people drink huge quantities of water daily as a matter of course, she says many experts now suggest that people simply heed the body's signals for hydration. The water in fruits and vegetables also count as part of your intake, says Amidor. The caveat, though, is that older people often lose their sense of thirst and need to be reminded to hydrate on a more regular basis. For the rest of us, making sure we have access to water as needed—in portable non-plastic containers—is a good option.

12 Reasons You're So Tired—and How to Get Back on Top

11. You're pre-diabetic.

Glucose supplies energy to the body and brain. It's not surprising that not enough glucose will make you extremely tired. But the same is true when you ingest too much, says Dr. Greene. Normally, the act of eating signals the body to produce insulin which, in turn, fuels the cells with energy. But, says Greene, when you're pre-diabetic, your body can become insulin-resistant—overeating or ingesting too many simple carbs is often a factor. The result is all that excess glucose doesn't get into the cells, but rather it gets stored as fat or spills into the urine, and you grow tired.

The fix: A fasting blood sugar test will determine if you're pre-diabetic, says Greene. If you fall into that category, consider it a wake-up call to change your eating and exercise habits. Greene recommends a Mediterranean-type diet, consisting of whole grains, lots of fruits and vegetables and moderate amounts of healthy fats.

12 Reasons You're So Tired—and How to Get Back on Top

12. You have sleep apnea.

Many people with sleep apnea don't even know they have it, says Michael Breus, Ph.D., a clinical psychologist in private practice whose specialty is sleep disorders. Sleep apnea, which is typically caused by anatomical problems, impels the sleeper to stop breathing, sometimes as many as 150 times an hour. When breathing shuts down, even for only a couple of seconds, there's less oxygen supplied to the brain. The body senses the danger and wakes you to breathe. "In severe cases, this constant waking is comparable to total sleep deprivation," says Breus, who's author of Beauty Sleep: Look Younger, Lose Weight and Feel Great through Better Sleep (Plume, 2007).

The fix: See a medical professional who's certified in sleep medicine or clinical sleep disorders, says Breus. You'll be referred to a sleep center for diagnosis. The most popular form of treatment is a continuous positive airway pressure machine (CPAP), which shoots air through the nasal passages and throat while you're asleep. Other solutions include using nose filters, dental appliances to help correct jaw displacement, or surgery to remove excess throat tissue which tends to accumulate in overweight people. Weight loss may eliminate the condition entirely in some cases, says Breus.

By Coeli Carr for MSN Health & Fitness