Weakness and Fatigue [en Español]
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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 required to move your arms, legs, or other muscles. If muscle weakness is the result of pain, the person may be able to make muscles work, but it will hurt.
- Fatigue is a feeling of tiredness or exhaustion or a need to rest because of lack of energy or strength. Fatigue may result from overwork, poor sleep, worry, boredom, or lack of exercise. It is a symptom that may be caused by illness, medicine, or medical treatment such as chemotherapy. Anxiety or depression can also cause fatigue.
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:
- A problem with the minerals ( electrolytes ) found naturally in the body, such as low levels of potassium or sodium.
- Infections, such as a urinary tract infection or a respiratory infection.
- 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.
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 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 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:
- 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.
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.
Check Your Symptoms
Make an Appointment
Based on your answers, the problem may not improve without medical care.
- Make an appointment to see your doctor in the next 1 to 2 weeks.
- If appropriate, try home treatment while you are waiting for the appointment.
- If symptoms get worse or you have any concerns, call your doctor. You may need care sooner.
Call 911 Now
Based on your answers, you need emergency care.
Call 911 or other emergency services now.
Call 911 Now
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.
Seek Care Today
Based on your answers, you may need care soon. The problem probably will not get better without medical care.
- Call your doctor today to discuss the symptoms and arrange for care.
- If you cannot reach your doctor or you don't have one, seek care today.
- If it is evening, watch the symptoms and seek care in the morning.
- If the symptoms get worse, seek care sooner.
Seek Care Now
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
- Call your doctor now to discuss the symptoms and arrange for care.
- If you cannot reach your doctor or you don't have one, seek care in the next hour.
- You do not need to call an
- You cannot travel safely either by driving yourself or by having someone else drive you.
- You are in an area where heavy traffic or other problems may slow you down.
Many prescription and nonprescription drugs can cause weakness and fatigue. A few examples are:
- Antianxiety medicines.
- High blood pressure medicines.
- Statin medicines for high cholesterol.
Heartbeat changes can include:
- A faster or slower heartbeat than is normal for you. This would include a pulse rate of more than 120 beats per minute (when you are not exercising) or less than 50 beats per minute (unless that is normal for you).
- A heart rate that does not have a steady pattern.
- Skipped beats.
- Extra beats.
Neurological symptoms—which may be signs of a problem with the nervous system—can affect many body functions. Symptoms may include:
- Numbness, weakness, or lack of movement in your face, arm, or leg, especially on only one side of your body.
- Trouble seeing in one or both eyes.
- Trouble speaking.
- Confusion or trouble understanding simple statements.
- Problems with balance or coordination (for example, falling down or dropping things).
Symptoms of a heart attack may include:
- Chest pain or pressure, or a strange feeling in the chest.
- Shortness of breath.
- Nausea or vomiting.
- Pain, pressure, or a strange feeling in the back, neck, jaw, or upper belly, or in one or both shoulders or arms.
- Lightheadedness or sudden weakness.
- A fast or irregular heartbeat.
The more of these symptoms you have, the more likely it is that you're having a heart attack. Chest pain or pressure is the most common symptom, but some people, especially women, may not notice it as much as other symptoms. You may not have chest pain at all but instead have shortness of breath, nausea, numbness, tingling, or a strange feeling in your chest or other areas.
Symptoms of serious illness may include:
- A severe headache.
- A stiff neck.
- Mental changes, such as feeling confused or much less alert.
- Extreme fatigue (to the point where it's hard for you to function).
- Shaking chills.
Symptoms of serious illness in a baby may include the following:
- The baby is limp and floppy like a rag doll.
- The baby doesn't respond at all to being held, touched, or talked to.
- The baby is hard to wake up.
Try Home Treatment
You have answered all the questions. Based on your answers, you may be able to take care of this problem at home.
- Try home treatment to relieve the symptoms.
- Call your doctor if symptoms get worse or you have any concerns (for example, if symptoms are not getting better as you would expect). You may need care sooner.
Many things can affect how your body responds to a symptom and what kind of care you may need. These include:
- Your age. Babies and older adults tend to get sicker quicker.
- Your overall health. If you have a condition such as diabetes, HIV, cancer, or heart disease, you may need to pay closer attention to certain symptoms and seek care sooner.
- Medicines you take. Certain medicines, herbal remedies, and supplements can cause symptoms or make them worse.
- Recent health events, such as surgery or injury. These kinds of events can cause symptoms afterwards or make them more serious.
- Your health habits and lifestyle, such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.
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
- 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.
- For more information, see Insomnia: Improving Your Sleep .
Symptoms to watch for during home treatment
Call your doctor if any of the following occur during home treatment:
- New symptoms develop along with the weakness and fatigue.
- Symptoms last longer than 2 weeks.
- Symptoms become more severe or more frequent.
Mild fatigue can often be prevented by changes in lifestyle habits.
- Get regular exercise. 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 .
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 ?
Primary Medical Reviewer William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Kathleen Romito, MD - Family Medicine
Adam Husney, MD - Family Medicine
Specialist Medical Reviewer David Messenger, MD
Current as ofMay 27, 2016
Current as of: May 27, 2016
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