6 Times Your Fatigue Is Something More Serious

We all feel tired from time to time, but if walking to the bathroom wipes you out, there may be a reason.

Medically reviewed in January 2020

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Fatigue is a state of mental and physical exhaustion that can leave you feeling weak and deflated. Temporary fatigue typically has an identifiable cause, and once the cause is remedied, will go away over time. Common culprits: too little sleep, a lack of exercise or poor die.

If your lethargy doesn’t have an identifiable cause, lasts for a long time or isn't remedied by restful sleep, it may be a sign of an underlying health condition, like anemia, thyroid disorders or diabetes.

Find out what might be the source of your long-term fatigue, and whether it's something you should discuss with your healthcare provider.

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Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a disorder that triggers extreme mental and physical exhaustion that can’t be explained by a medical condition, doesn’t improve with sleep and often limits your abilities to do everyday activities. Other symptoms include exhaustion that lasts 24 hours or longer after strenuous mental or physical effort, loss of memory and concentration, muscle pain, new or worsening headaches and a sore throat.

Between 836,000 and 2.5 million Americans have the condition, according to a 2015 report by the National Academy of Medicine, though most have not been diagnosed. It most commonly affects people in their 40s and 50s; women who have a hard time managing stress may be at a higher risk.

The root causes of CFS are still unknown, which makes diagnosis and treatment difficult. The disorder is diagnosed using tests that rule out other conditions with similar symptoms, like sleep apnea, depression and anemia.

Treatment can help reduce symptoms, and might include prescription sleep aids and therapy. Changing the way you handle stress, improving your sleep habits and monitoring your activity throughout the day may also be helpful.

Phone applications like Sharecare, available for iOS and Android can help you keep track of your sleep and daily physical activity. Simply download the app to automatically track your nightly rest and the number of steps you take throughout the day. You can manually log these numbers, too, if that’s what you prefer.

Regardless of what you think is causing your fatigue, any periods of excessive sleepiness should be discussed with your doctor. 

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Heart disease

Heart disease is the leading killer of American men and women, responsible for 1 in 4 US deaths. While some people show no symptoms, common red flags for heart attacks, heart failure and related conditions include:

  • Chest pain and tightness
  • Shortness of breath
  • Swelling in the legs and abdomen

For many—especially women—the symptoms of heart disease can also include fatigue, lightheadedness and a hard time completing everyday tasks. It happens because the tissues in your body don't receive enough blood from the heart.

If you experience this exhaustion, especially with other heart disease symptoms, your doctor can use stress tests, chest x-rays, blood tests and an electrocardiogram—which measures the heart’s activity—to get to the root of the problem. You can reduce your risks with medication and lifestyle changes, like a healthy diet and more exercise.

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Diabetes is a condition characterized by high glucose, or blood sugar levels. It affects more than 30 million Americans, and obesity, inactivity and a family history of the disease all increase your risk. Excessive thirst, frequent urination, blurred vision, weight fluctuations—and of course, fatigue—are signs of diabetes.

Diabetes causes fatigue in a lot of ways. It can happen when sugar builds up in the blood; whatever the kidneys can’t break down leaves the body in your urine. Excess urination, in turn, can lead to dehydration, which may make you tired. Hypoglycemia and fluctuations in blood sugar can also cause fatigue.

There’s more. Our bodies use sugar for energy, but if the body can’t process these sugars, our energy levels can drop.

If you experience fatigue along with other symptoms of diabetes, make an appointment with a healthcare provider, who will test your urine for elevated levels of glucose and may also prescribe medication and recommend lifestyle changes.

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Anemia happens when you don't have adequate red blood cells, which are responsible for carrying oxygen throughout your body. It can also occur if your body is too low in iron to produce enough hemoglobin, an iron-rich protein in your red blood cells; this is known as iron deficiency anemia. A third type of anemia, pernicious anemia, is the result of too little vitamin B12, and is common among seniors and vegetarians.

Milder cases of anemia may be symptom-less, but the most common sign in severe cases is fatigue, likely caused by a lack of oxygen getting to your tissues. Other symptoms of anemia include shortness of breath, dizziness or cold hands and feet. Iron deficiency anemia can also cause:

  • Brittle nails
  • Swelling of the tongue
  • Cravings for non-food items, like dirt
  • Restless legs syndrome, a sleep disorder that causes a strong urge to move your legs

To address your anemia, your doctor may suggest a healthy diet high in iron-rich foods like lentils, tofu, lean beef and even dark chocolate. Other recommendations may include iron supplements and in rare cases, blood transfusions.

Treatment options for pernicious anemia include B12 shots, supplements and a diet rich in B12. Load your plate with foods like clams, trout and salmon.

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Thyroid disorders

Located in your neck, the thyroid gland secretes hormones that affect weight, energy levels, metabolism and the function of nearly every organ. When your thyroid is out of whack, it can produce too much (hyperthyroidism) or too little (hypothyroidism) of those necessary hormones. Both hyperthyroidism and hypothyroidism may cause fatigue, as well as weight fluctuations, changes in menstruation and muscle aches and weakness.

If you experience fatigue along with these other symptoms, and fear a thyroid disorder may be to blame, speak with your doctor. Your doctor can diagnose thyroid conditions using your medical history, physical exams and tests, which measure the levels of thyroid-producing substances in the body.

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Fatigue is one of the most common signs of cancer, and one of the most common side effects of cancer treatment. The causes of cancer-related fatigue are somewhat unknown, but researchers believe it may be linked to toxic chemicals formed by the cancer cells in the body, or by protein and hormonal changes caused by abnormal cells.

Other general symptoms include weight loss, fever and unexplained pain, though it can also cause localized symptoms since it affects each part of the body differently. For example, lung cancer may trigger a nagging cough, while blood in your stool or urine could signal colon or bladder cancer. If you're fatigued, look for these other red flags, which can indicate a larger problem.

Don’t wait to see your healthcare provider if you fear cancer is the underlying cause of your fatigue. Speedy treatment, which might include chemotherapy, radiation therapy, surgery or any combination thereof, is important.

If you've been diagnosed already, your doctor can suggest ways to manage cancer-related fatigue. These might include an exercise regimen, short naps, a nighttime sleep schedule, a healthy diet plan and yoga to relieve stress.

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