Health Topic

Fatigue

Are you tired? Find out about some of the common and uncommon causes of fatigue and how to help yourself.

Reviewed Reviewed by a registered pharmacistGeneral information

Also called: Tiredness · Weariness

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Fatigue

Fatigue is a feeling of weariness, tiredness, or lack of energy. It can interfere with your usual daily activities. Fatigue can be a normal response to physical activity, emotional stress, boredom, or lack of sleep. But sometimes it can be a sign of a mental or physical condition. If you have been feeling tired for weeks, contact your health care provider. They can help you find out what's causing your fatigue and recommend ways to relieve it.

Fatigue itself is not a disease; it's a symptom. It can have many different causes, including pregnancy and various medical problems, treatments, and lifestyle habits such as:

  • Medical problems: Chronic (long-lasting) diseases such as diabetes, COPD (chronic obstructive pulmonary disease), and heart, liver, kidney and thyroid diseases
  • Untreated pain and diseases like fibromyalgia
  • Anemia
  • Infections
  • Parkinson's disease
  • Sleep apnea and other sleep disorders
  • Recent stroke
  • Mental disorders such as depression and anxiety
  • Cancer treatments such as chemotherapy, radiation, and bone marrow transplants
  • Recovering from major surgery
  • Taking certain medicines, such as antidepressants, antihistamines, and medicines for nausea and pain
  • Not getting enough sleep
  • Staying up too late
  • Drinking too much alcohol
  • Substance use
  • Having too much caffeine (which can keep you from getting a good night's sleep)
  • Getting too little or too much exercise

Overwhelming fatigue is part of a disorder called myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The fatigue caused by this disorder is different from a tired feeling that goes away after you rest. Instead, the fatigue in ME/CFS lasts a long time, does not get better with rest, and limits your ability to do ordinary daily activities.

If you've had fatigue that does not get better after several weeks, call your provider. They will ask questions about your sleep, daily activities, appetite, and exercise. They will likely do a physical exam and order lab tests. Once they decide on a diagnosis, they can tell you what treatments might help.

You can also make some lifestyle changes to feel less tired:

  • Get regular physical activity
  • Improve your sleep habits
  • Stop smoking (if you smoke), since smoking is linked to many diseases that can cause fatigue
  • Manage stress
  • Eat a healthy diet and avoid alcohol

It also may be helpful for you to keep a fatigue diary. This can help you find patterns throughout the day, such as when you feel more tired and when you have more energy. It can also help you plan for activities that may give you more energy.

It sits within Symptoms.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Fatigue

3,456 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Related Issues

Genetics

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Fatigue. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Fatigue, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.