Weakness and Fatigue

Topic Overview

Weakness and fatigue are terms that are often used as if they mean the same thing, but in fact they describe two different sensations. It is important to know exactly what you mean when you say "I feel weak" or "I am fatigued" because it can help you and your doctor narrow down the possible causes of your symptoms.

• Weakness is a lack of physical or muscle strength and the feeling that extra effort is needed to perform daily activities that require you to move your arms, legs, or other muscles.
• Fatigue is a feeling of tiredness, exhaustion, or lack of energy.

Both weakness and fatigue are symptoms, not diseases. Because these symptoms can be caused by many other health problems, the importance of weakness and fatigue can only be determined when other symptoms are evaluated.

Weakness

General weakness often occurs after you have done too much activity at one time, such as by taking an extra-long hike. You may feel weak and tired, or your muscles may be sore. These sensations usually go away within a few days.

In rare cases, generalized muscle weakness may be caused by another health problem, such as:

• Problems with the thyroid gland, which regulates the way the body uses energy.
  • A low thyroid level (hypothyroidism) can cause fatigue, weakness, lethargy, weight gain, depression, memory problems, constipation, dry skin, intolerance to cold, coarse and thinning hair, brittle nails, or a yellowish tint to the skin.
  • A high thyroid level (hyperthyroidism) can cause fatigue, weight loss, increased heart rate, intolerance to heat, sweating, irritability, anxiety, muscle weakness, and thyroid enlargement.
• Guillain-Barré syndrome, a rare nerve disorder that causes weakness in the legs, arms, and other muscles and that can progress to complete paralysis.
• Myasthenia gravis, a rare, chronic disorder that causes weakness and rapid muscle fatigue.
• A problem with the minerals (electrolytes) found naturally in the body, such as low levels of potassium or sodium.

Muscle weakness that is slowly getting worse requires a visit to a doctor.

Sudden muscle weakness and loss of function in one area of the body can indicate a serious problem within the brain (such as a stroke or transient ischemic attack) or spinal cord or with a specific nerve in the body.

Fatigue

Fatigue is a feeling of tiredness, exhaustion, or lack of energy. You may feel mildly fatigued because of overwork, poor sleep, worry, boredom, or lack of exercise. Any illness, such as a cold or the flu, may cause fatigue, which usually goes away as the illness clears up. Most of the time, mild fatigue occurs with a health problem that will improve with home treatment and does not require a visit to a doctor.

A stressful emotional situation may also cause fatigue. This type of fatigue usually clears up when the stress is relieved.

Many prescription and nonprescription medicines can cause weakness or fatigue. The use or abuse of alcohol, caffeine, or illegal drugs can cause fatigue.

A visit to a doctor usually is needed when fatigue occurs along with more serious symptoms, such as increased breathing difficulties, signs of a serious illness, abnormal bleeding, or unexplained weight loss or gain.

Fatigue that lasts longer than 2 weeks usually requires a visit to a doctor. This type of fatigue may be caused by a more serious health problem, such as:

• A decrease in the amount of oxygen-carrying substance (hemoglobin) found in red blood cells (anemia).
• Problems with the heart, such as coronary artery disease or heart failure, that limit the supply of oxygen-rich blood to the heart muscle or the rest of the body.
• Metabolic disorders, such as diabetes, in which sugar (glucose) remains in the blood rather than entering the body's cells to be used for energy.
• Problems with the thyroid gland, which regulates the way the body uses energy.
  • A low thyroid level (hypothyroidism) can cause fatigue, weakness, lethargy, weight gain, depression, memory problems, constipation, dry skin, intolerance to cold, coarse and thinning hair, brittle nails, or a yellowish tint to the skin.
  • A high thyroid level (hyperthyroidism) can cause fatigue, weight loss, increased heart rate, intolerance to heat, sweating, irritability, anxiety, muscle weakness, and thyroid enlargement.
• Kidney disease and liver disease, which cause fatigue when the concentration of certain chemicals in the blood builds up to toxic levels.

Chronic fatigue syndrome is an uncommon cause of severe, persistent fatigue.

If fatigue occurs without an obvious cause, it is important to evaluate your mental health. Fatigue is a common symptom of mental health problems, such as anxiety or depression. Fatigue and depression may become so severe that you may consider suicide as a way to end your pain. If you think your fatigue may be caused by a mental health problem, see your doctor.

Review the Emergencies and Check Your Symptoms sections to determine if and when you need to see a doctor.

Emergencies

• Loss of function in one area of your body, such as:
  • Partial or complete inability to move (paralysis) in part or all of one side of your body (face, arm, and leg)
  • Persistent numbness
  • Loss of vision in one or both eyes
  • Inability to speak, difficulty speaking, or difficulty understanding speech
• Sudden weakness of the entire body with or without unexplained chest pain that is crushing or squeezing, feels like a heavy weight on the chest, or occurs with any other symptoms of a heart attack
• Sudden, severe pain and is the worst headache you have ever had
• Confusion or a change in behavior, such as unusually aggressive or combative behavior
• A change in your mental health and you are seriously considering suicide

Check Your Symptoms

If you answer yes to any of the following questions, click on the "Yes" in front of the question for information about how soon to see a health professional.

Review health risks that may increase the seriousness of your symptoms.

If you have any of the following symptoms, evaluate those symptoms first.

• Chest pain: Go to the topic Chest Pain.
• Change in your heart rate: Go to the topic Change in Heartbeat.
• Headache: Go to the topic Headaches.
• Thoughts of suicide or harming yourself: Go to the topic Suicidal Thoughts or Threats.
• A sleep problem: Go the topic Sleep Problems, Age 12 and Older.

	Yes	Have you had weakness with a temporary loss of function, but all your symptoms are improving or are now gone? When to See a Doctor See significance of weakness with a temporary loss of function if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Call your health professional immediately if you answer "Yes" to any of the following questions. Yes Did you have a temporary inability to move (paralysis) part or all of one side of your body? Yes Did you have temporary confusion or altered behavior? Yes Did you have a temporary inability to speak, difficulty speaking, or difficulty understanding speech? Yes Did you have temporary numbness? Yes Did you have temporary vision changes, such as dimness, blurring, or double vision? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you have persistent generalized weakness? When to See a Doctor See significance of generalized weakness if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Call your health professional immediately if you answer "Yes" to the following question. Yes Is your weakness rapidly getting worse, and you think you may soon be unable to function? Call your health professional today if you answer "Yes" to the following question. Yes Has your weakness gradually become so severe that you are unable to complete your daily activities? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to the following question. Yes Have you had mild to moderate muscle weakness that has not improved after 2 weeks of home treatment? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you think your fatigue is caused by a mental health problem? When to See a Doctor See significance of a mental health problem if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Call your health professional immediately if you answer "Yes" to the following question. Yes Are you thinking of committing suicide but you do not have a plan? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to any of the following questions. Yes Has fatigue caused you to limit your usual activities for longer than 2 weeks despite home treatment? Yes Do you still feel fatigued despite 4 weeks of home treatment? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you think that your weakness or fatigue may be caused by a medicine? When to See a Doctor See significance of medicine if you need information to help you answer the question below. Review health risks that may increase the seriousness of your symptoms. Call your health professional today if you answer "Yes" to the following question. Yes Do you think that your generalized weakness or fatigue may be caused by a prescription or nonprescription medicine? Note: If you answered "Yes": Call the doctor who prescribed the medicine to determine whether you should stop taking the medicine or take a different one. An appointment may not be needed. If you are taking a nonprescription medicine, stop taking the medicine. Call your doctor if you feel you need to continue taking the medicine. If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you think that alcohol or other drugs may be causing your fatigue? When to See a Doctor See significance of alcohol or other drugs if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Call your health professional today if you answer "Yes" to any of the following questions. Yes Do you have an alcohol or drug abuse problem and you recognize your need for help? Yes Are you using alcohol or drugs after participating in a drug or alcohol treatment program? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to the following question. Yes Do you think that caffeine may be the cause of your fatigue but you feel unable to stop using caffeine? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you have persistent fatigue? When to See a Doctor See significance of persistent fatigue if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. You may wait to see if the symptoms improve over the next 24 hours (or specified time period) if you answer "Yes" to the following question. Yes Have you been unable to complete your daily activities for longer than 24 hours? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to any of the following questions. Yes Have you had to limit your usual activities for 2 weeks or longer, after home treatment? Yes Do you still feel fatigued after 2 weeks of home treatment? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Has your fatigue lasted longer than 2 weeks after you have had symptoms of another illness? When to See a Doctor See significance of symptoms of another illness if you need information to help you answer the question below. Review health risks that may increase the seriousness of your symptoms. You need an appointment within the next 1 to 2 weeks if you answer "Yes" to the following question. Yes Has your fatigue lasted longer than 2 weeks after symptoms of another illness have gone away? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you have fatigue and unexplained weight gain or weight loss? When to See a Doctor See significance of unexplained weight gain or weight loss if you need information to help you answer the question below. Review health risks that may increase the seriousness of your symptoms. You need an appointment within the next 1 to 2 weeks if you answer "Yes" to any of the following questions. Yes Have you had an unexplained weight gain of 5 lb (2 kg) or more over the past 3 months? Yes Have you had an unexplained weight loss of 5 lb (2 kg) or more over the past 3 months? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Other Symptoms to Watch For

Fatigue is often a symptom of another condition. If you have any other symptoms, evaluate those symptoms using the appropriate topic:

• Abdominal Pain, Age 12 and Older
• Abnormal Vaginal Bleeding
• Anxiety
• Confusion, Memory Loss, and Altered Alertness
• Diarrhea, Age 12 and Older
• Feeling Depressed
• Fever, Age 4 and Older
• Respiratory Problems, Age 12 and Older
• Urinary Problems, Age 12 and Older

If a visit to a health professional is not needed immediately, see the Home Treatment section for self-care information.

Emergencies

• Loss of function in one area of your body, such as:
  • Partial or complete inability to move (paralysis) in part or all of one side of your body (face, arm, and leg)
  • Persistent numbness
  • Loss of vision in one or both eyes
  • Inability to speak, difficulty speaking, or difficulty understanding speech
• Sudden weakness of the entire body with or without unexplained chest pain that is crushing or squeezing, feels like a heavy weight on the chest, or occurs with any other symptoms of a heart attack
• Sudden, severe pain and is the worst headache you have ever had
• Confusion or a change in behavior, such as unusually aggressive or combative behavior
• A change in your mental health and you are seriously considering suicide

Check Your Symptoms

If you answer yes to any of the following questions, click on the "Yes" in front of the question for information about how soon to see a health professional.

Review health risks that may increase the seriousness of your symptoms.

If you have any of the following symptoms, evaluate those symptoms first.

• Chest pain: Go to the topic Chest Pain.
• Change in your heart rate: Go to the topic Change in Heartbeat.
• Headache: Go to the topic Headaches.
• Thoughts of suicide or harming yourself: Go to the topic Suicidal Thoughts or Threats.
• A sleep problem: Go the topic Sleep Problems, Age 12 and Older.

	Yes	Have you had weakness with a temporary loss of function, but all your symptoms are improving or are now gone? When to See a Doctor See significance of weakness with a temporary loss of function if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Call your health professional immediately if you answer "Yes" to any of the following questions. Yes Did you have a temporary inability to move (paralysis) part or all of one side of your body? Yes Did you have temporary confusion or altered behavior? Yes Did you have a temporary inability to speak, difficulty speaking, or difficulty understanding speech? Yes Did you have temporary numbness? Yes Did you have temporary vision changes, such as dimness, blurring, or double vision? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you have persistent generalized weakness? When to See a Doctor See significance of generalized weakness if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Call your health professional immediately if you answer "Yes" to the following question. Yes Is your weakness rapidly getting worse, and you think you may soon be unable to function? Call your health professional today if you answer "Yes" to the following question. Yes Has your weakness gradually become so severe that you are unable to complete your daily activities? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to the following question. Yes Have you had mild to moderate muscle weakness that has not improved after 2 weeks of home treatment? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you think your fatigue is caused by a mental health problem? When to See a Doctor See significance of a mental health problem if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Call your health professional immediately if you answer "Yes" to the following question. Yes Are you thinking of committing suicide but you do not have a plan? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to any of the following questions. Yes Has fatigue caused you to limit your usual activities for longer than 2 weeks despite home treatment? Yes Do you still feel fatigued despite 4 weeks of home treatment? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you think that your weakness or fatigue may be caused by a medicine? When to See a Doctor See significance of medicine if you need information to help you answer the question below. Review health risks that may increase the seriousness of your symptoms. Call your health professional today if you answer "Yes" to the following question. Yes Do you think that your generalized weakness or fatigue may be caused by a prescription or nonprescription medicine? Note: If you answered "Yes": Call the doctor who prescribed the medicine to determine whether you should stop taking the medicine or take a different one. An appointment may not be needed. If you are taking a nonprescription medicine, stop taking the medicine. Call your doctor if you feel you need to continue taking the medicine. If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you think that alcohol or other drugs may be causing your fatigue? When to See a Doctor See significance of alcohol or other drugs if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Call your health professional today if you answer "Yes" to any of the following questions. Yes Do you have an alcohol or drug abuse problem and you recognize your need for help? Yes Are you using alcohol or drugs after participating in a drug or alcohol treatment program? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to the following question. Yes Do you think that caffeine may be the cause of your fatigue but you feel unable to stop using caffeine? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you have persistent fatigue? When to See a Doctor See significance of persistent fatigue if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. You may wait to see if the symptoms improve over the next 24 hours (or specified time period) if you answer "Yes" to the following question. Yes Have you been unable to complete your daily activities for longer than 24 hours? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to any of the following questions. Yes Have you had to limit your usual activities for 2 weeks or longer, after home treatment? Yes Do you still feel fatigued after 2 weeks of home treatment? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Has your fatigue lasted longer than 2 weeks after you have had symptoms of another illness? When to See a Doctor See significance of symptoms of another illness if you need information to help you answer the question below. Review health risks that may increase the seriousness of your symptoms. You need an appointment within the next 1 to 2 weeks if you answer "Yes" to the following question. Yes Has your fatigue lasted longer than 2 weeks after symptoms of another illness have gone away? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
	Yes	Do you have fatigue and unexplained weight gain or weight loss? When to See a Doctor See significance of unexplained weight gain or weight loss if you need information to help you answer the question below. Review health risks that may increase the seriousness of your symptoms. You need an appointment within the next 1 to 2 weeks if you answer "Yes" to any of the following questions. Yes Have you had an unexplained weight gain of 5 lb (2 kg) or more over the past 3 months? Yes Have you had an unexplained weight loss of 5 lb (2 kg) or more over the past 3 months? If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Other Symptoms to Watch For

Fatigue is often a symptom of another condition. If you have any other symptoms, evaluate those symptoms using the appropriate topic:

• Abdominal Pain, Age 12 and Older
• Abnormal Vaginal Bleeding
• Anxiety
• Confusion, Memory Loss, and Altered Alertness
• Diarrhea, Age 12 and Older
• Feeling Depressed
• Fever, Age 4 and Older
• Respiratory Problems, Age 12 and Older
• Urinary Problems, Age 12 and Older

If a visit to a health professional is not needed immediately, see the Home Treatment section for self-care information.

Home Treatment

If you have generalized weakness and fatigue along with other symptoms, evaluate those symptoms. Home treatment for your other symptoms usually will improve your weakness and fatigue. Mild generalized weakness and fatigue that occur with a viral illness usually improve with the following home treatment measures.

• Get extra rest while you are ill. Let your symptoms be your guide.
  • If you have a cold, you may be able to stick to your usual routine and just get some extra sleep.
  • If you have the flu, you may need to spend a few days in bed.
• Return to your usual activities slowly to avoid prolonging the fatigue.
• Be sure to drink extra fluids to avoid dehydration.

If generalized weakness and fatigue are not related to another illness, follow the guidelines in the Prevention section and be patient. It may take a while for you to feel energetic again.

• Listen to your body. Alternate rest with exercise. Gradually increasing your exercise may help decrease your fatigue.
• Limit medicines that might contribute to fatigue. Tranquilizers and cold and allergy medicines often cause fatigue.
• Improve your diet. Eating a balanced diet may increase your energy level. Do not skip meals, especially breakfast.
• Reduce your use of alcohol or other drugs, such as caffeine or nicotine, which may contribute to fatigue.
• Cut back on watching television. Spend that time with friends, try new activities, or travel to break the fatigue cycle.
• Get a good night's sleep. This may be the first step toward controlling fatigue.
  • Eliminate all sound and light disturbances.
  • Do not eat just before you go to bed.
  • Use your bed only for sleeping. Do not read or watch TV in bed.
  • Get regular exercise but not within 3 to 4 hours of your bedtime.

Symptoms to Watch For During Home Treatment

Use the Check Your Symptoms section to evaluate your symptoms if any of the following occur during home treatment:

• New symptoms develop along with the weakness and fatigue.
• Depression or anxiety increases despite home treatment.
• Symptoms of weakness or fatigue increase despite home treatment.
• Symptoms do not improve after 2 weeks of home treatment.
• Symptoms become more severe or more frequent.

Prevention

Mild fatigue can often be prevented by changes in lifestyle habits.

• Regular exercise is your best defense against fatigue. If you feel too tired to exercise vigorously, try taking a short walk.
• Eat a balanced diet. Do not skip meals, especially breakfast.
• Get enough sleep.
• Deal with emotional problems instead of ignoring or denying them.
• Take steps to control your stress and workload. For more information, see the topic Stress Management in the Related Information section.

Preparing For Your Appointment

To prepare for your appointment, see the topic Making the Most of Your Appointment.

You can help your doctor diagnose and treat your condition by being prepared to answer the following questions:

• What is your major symptom, weakness or fatigue?
• Have you had these symptoms before? If so:
  • Did you see a doctor for an evaluation of your symptoms?
  • What was the diagnosis?
  • How were your symptoms treated?
• What other symptoms do you have that may be related to your major symptom?
• How long have you had your symptoms? Describe what was happening when you first noticed your symptoms.
• What makes your symptoms better or worse?
• What home treatment have you tried?
• Are you experiencing any particular stress at home, work, or school that could be causing your weakness or fatigue?
• Are you using any alcohol or other drugs, such as caffeine or nicotine, that may be causing fatigue?
• What medicines have you used, both prescription and nonprescription?
• Do you have any health risks?

While you are waiting for your appointment, it may be helpful to keep a diary of your symptoms (What is a PDF document?) .

Related Information

• Abnormal Vaginal Bleeding
• Alcohol and Drug Problems
• Anxiety
• Chronic Fatigue Syndrome
• Confusion, Memory Loss, and Altered Alertness
• Coronary Artery Disease
• Depression
• Feeling Depressed
• Fibromyalgia
• Healthy Eating
• Hypothyroidism
• Infectious Mononucleosis
• Lyme Disease
• Respiratory Problems, Age 12 and Older
• Stress Management
• Stroke
• Transient Ischemic Attack (TIA)

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