Fatigue, Tired: 170 Possible Causes
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What causes fatigue and tired? 170 possible conditions

See a list of possible causes in order from the most common to the least.


Common Cold Overview

The common cold is a virus that involves symptoms like sneezing, a runny nose and a headache. Learn the causes, symptoms and treatments for the common cold now!

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Cold and Flu Overview

Common colds and influenza are contagious infections that affect the respiratory system. Both are airborne illnesses, spread through coughing and sneezing. Shared symptoms include headache, cough, sore throat, and more.

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CFS (Chronic Fatigue Syndrome)

Chronic fatigue syndrome (CFS) is a debilitating disorder characterized by extreme tiredness that can't be explained by an underlying medical condition.

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Anemia happens when the number of healthy red blood cells in your body is too low. Red blood cells carry oxygen to all of the body's tissues.

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Congestive Heart Failure (CHF)

Congestive heart failure (CHF) is a chronic condition that affects the chambers of your heart. CHF refers to fluid buildup around your heart.

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Sleeplessness, or insomnia, is a serious sleep disorder. It can mean the inability to fall asleep or stay asleep throughout the night, or the tendency to wake too early before having gotten enough sleep.

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There are many symptoms of HIV/AIDS, including persistent skin rashes, night sweats, and mouth sores.

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This condition is considered a medical emergency. Urgent care may be required.

Dehydration takes place when your body loses more fluid than you drink. The most common cause of water loss from the body is excessive sweating.

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Low Blood Sugar (Hypoglycemia)

This condition is considered a medical emergency. Urgent care may be required.

Hypoglycemia, or low blood sugar, is a potentially dangerous condition that's most common in people with diabetes. Learn what causes it and how to prevent it.

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What is Fibromyalgia?

Fibromyalgia is a chronic disorder characterized by widespread, unexplained pain in tender points in muscles and joints, including the head, neck, and sides of hips.

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Learn more about anxiety with this overview of anxiety disorders.

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Obesity is an epidemic in the U.S. This condition puts people at a higher risk for serious diseases, such as type 2 diabetes, heart disease, and cancer.

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Chronic Bronchitis

Learn about the causes and treatment of acute bronchitis.

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Infectious Mononucleosis

Infectious mononucleosis, or mono, refers to a group of symptoms usually caused by the Epstein-Barr virus (EBV).

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Bipolar Disorder

Bipolar disorder is a mental illness marked by extreme shifts in mood ranging from mania to depression. It is also called bipolar disease or manic depression.

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The thyroid gland produces a hormone that controls how your cells use energy (metabolize). Hypothyroidism occurs when the body doesn't produce enough. Untreated, it can cause complications like obesity and heart disease.

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Low Blood Potassium

Hypokalemia occurs when the blood's potassium levels are too low. A normal level of potassium is 3.6-5.2 millimoles per liter. Levels below 3.6 are considered low.

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Low Blood Sodium (Hyponatremia)

Low blood sodium, or hyponatremia, occurs when water and sodium are out of balance in your body. A quick drop in sodium levels can cause weakness, headache, nausea, and muscle cramps.

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Congestive (Dilated) Cardiomyopathy

Congestive cardiomyopathy, also known as dilated cardiomyopathy, is characterized by a weak primary pumping chamber in the heart. Your heart automatically attempts to correct for this inefficiency. In turn, thi...

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Failure to Thrive

Your child may be diagnosed with failure to thrive if he or she falls below a healthy weight and shows signs of emotional underdevelopment. Typically, failure to thrive is discovered during a child's infant years. Idea...

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This feature is for informational purposes only and should not be used to diagnose.
Please consult a healthcare professional if you have health concerns.