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 intense fatigue that cannot be cured with sleep. Mental and physical activities may cause symptoms to worsen. When fatigue cannot be linked to ...

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Anemia occurs when the number of healthy red blood cells (RBCs) in the body is too low. Red cells carry oxygen to all the body's tissues, so a low red blood cell count indicates that the amount of oxygen in the blood i...

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Congestive Heart Failure (CHF)

Congestive heart failure is a chronic condition that affects the four chambers of the heart. Early symptoms include fatigue and weight gain. Irregular heart beat and wheezing indicate a worsening.

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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 the autoimmune disease 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 occurs when you lose more fluid than you drink. The most common cause of water loss from the body is excessive sweating. Headaches, dizziness, and decreased urination are symptoms.

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Low Blood Sugar (Hypoglycemia)

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

Also known as hypoglycemia, low blood sugar can be a dangerous condition. Hypoglycemia is rare in people who are not suffering from diabetes, the chronic disease that affects the body's ability to regulate blood sugar...

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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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What is anxiety? Anxiety often manifests itself as an apprehension about daily life. Learn the basics with this overview of the types of anxiety disorders.

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Obesity is defined as having a body mass index (BMI) of 30 or more. BMI is calculated using a person's weight and height. It can lead to other conditions like diabetes, heart disease, and cancer.

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Chronic Bronchitis

People often develop acute bronchitis after a viral chest infection. Blue-colored lips ankle or foot swelling can result.

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Infectious Mononucleosis

Infectious mononucleosis, or "mono," is a group of symptoms caused by the Epstein-Barr virus. One potential symptom is a pink rash that looks like the measles.

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Bipolar Disorder

Bipolar disorder mental illness marked by extreme from mania to depression. Bipolar disorder 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.
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