• Infection and disorders of the body's defense system (immune system).
• Physical exhaustion.
• Internal bleeding or other blood loss that results in a lack of red blood cells (anemia).
• Dehydration.
• An imbalance in mineral (electrolyte) levels, such as potassium.
• Chronic kidney or liver disease.
• Cancer.

• Some medicines or cancer treatment.
• Stress, anxiety, or depression.
• Heart disease, circulation problems, or stroke.
• Nervous system disorders.
• Thyroid disorders.
• Loss of muscle strength because of age or inactivity.
• Poor sleep quality or sleep disorders.

The cause of your weakness may not be known. Some causes of weakness can be serious, so it is important to see your health care provider.

Follow these instructions at home:

Activity

• Rest as needed.
• Try to get enough sleep. Most adults need 7–8 hours of quality sleep each night. Talk to your health care provider about how much sleep you need.
• Do exercises, such as arm curls and leg raises, for 30 minutes at least 2 days a week or as told by your health care provider. This helps build muscle strength.
• Consider working with a physical therapist or trainer who can develop an exercise plan to help you gain muscle strength.

General instructions

• Take over-the-counter and prescription medicines only as told by your health care provider.
• Eat a healthy, well-balanced diet. This includes:
  • Proteins to build muscles, such as lean meats and fish.
  • Fresh fruits and vegetables.
  • Carbohydrates to boost energy, such as whole grains.
• Drink enough fluid to keep your urine pale yellow.
• Keep all follow-up visits. This is important.

Contact a health care provider if:

• Your weakness does not improve or gets worse.
• Your weakness affects your ability to think clearly.
• Your weakness affects your ability to do your normal daily activities.

Get help right away if:

• You develop sudden weakness, especially on one side of your face or body.
• You have chest pain.
• You have trouble breathing or shortness of breath.
• You have problems with your vision.
• You have trouble talking or swallowing.
• You have trouble standing or walking.
• You are light-headed or lose consciousness.

• Do not wait to see if the symptoms will go away.
• Do not drive yourself to the hospital.

Summary

• Weakness is a lack of strength. You may feel weak all over your body or just in one specific part of your body.
• Weakness can be caused by a variety of things. In some cases, the cause may be unknown.
• Rest as needed, and try to get enough sleep. Most adults need 7–8 hours of quality sleep each night.
• Eat a healthy, well-balanced diet.