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Home > Health Library > Weakness and Fatigue
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.
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 be determined only when other symptoms are evaluated.
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:
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 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 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 problems, 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:
Myalgic encephalomyelitis/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.
Check your symptoms to decide if and when you should see a doctor.
Health Tools help you make wise health decisions or take action to improve your health.
Many things can affect how your body responds to a symptom and what kind of care you may need. These include:
You have answered all the questions. Based on your answers, you may be able to take care of this problem at home.
Symptoms of serious illness may include:
Symptoms of serious illness in a baby may include the following:
Symptoms of a heart attack may include:
For men and women, the most common symptom is chest pain or pressure. But women are somewhat more likely than men to have other symptoms, like shortness of breath, nausea, and back or jaw pain.
Neurological symptoms—which may be signs of a problem with the nervous system—can affect many body functions. Symptoms may include:
Heartbeat changes can include:
Many prescription and nonprescription drugs can cause weakness and fatigue. A few examples are:
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
Based on your answers, you may need care soon. The problem probably will not get better without medical care.
Based on your answers, you need emergency care.
Call 911 or other emergency services now.
After you call 911, the operator may tell you to chew 1 adult-strength (325 mg) or 2 to 4 low-dose (81 mg) aspirin. Wait for an ambulance. Do not try to drive yourself.
Sometimes people don't want to call 911. They may think that their symptoms aren't serious or that they can just get someone else to drive them. Or they might be concerned about the cost. But based on your answers, the safest and quickest way for you to get the care you need is to call 911 for medical transport to the hospital.
Based on your answers, the problem may not improve without medical care.
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.
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.
Call your doctor if any of the following occur during home treatment:
Mild fatigue can often be prevented by changes in lifestyle habits.
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:
While you are waiting for your appointment, it may be helpful to keep a diary of your symptoms .
Current as of:
July 1, 2021
Author: Healthwise StaffMedical Review: William H. Blahd Jr. MD, FACEP - Emergency MedicineKathleen Romito MD - Family MedicineE. Gregory Thompson MD - Internal MedicineAdam Husney MD - Family Medicine
Current as of: July 1, 2021
Author: Healthwise Staff
Medical Review:William H. Blahd Jr. MD, FACEP - Emergency Medicine & Kathleen Romito MD - Family Medicine & E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine
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