Fatigue

Category: General & Whole-Body Symptoms · All general symptoms

What it can feel like

Fatigue is a persistent tiredness that does not lift properly with rest — feeling drained, heavy and without energy for ordinary tasks. It is different from normal tiredness after a busy day, and it is one of the most common symptoms people bring to a clinician.

Possible causes

A symptom can have many causes, and most are not serious. The lists below group conditions this symptom can be associated with — common causes first. They are possibilities to discuss with a clinician, not a diagnosis.

Common causes

Fatigue can be associated with poor sleep, stress and overwork, with recovering from a virus, with low iron or anaemia, with an underactive thyroid, and with low mood. Lifestyle factors such as alcohol, irregular meals and very low activity also contribute.

Other possible causes

Fatigue can also be associated with diabetes, kidney or liver problems, heart conditions, sleep apnoea, vitamin deficiencies and, less commonly, inflammatory conditions or cancer. A new, persistent fatigue that is out of proportion deserves investigation.

Red flags — when to seek help promptly

Fatigue with unexplained weight loss, fever or night sweats
Fatigue with chest pain, breathlessness or palpitations
Fatigue with pale skin, dizziness or fainting
Fatigue so severe you cannot manage ordinary daily activities
Fatigue with thoughts of harming yourself — seek help the same day

What a clinician may do

A clinician will ask about sleep, mood, work, medicines and other symptoms, and examine you. Blood tests are commonly arranged — typically including blood count, iron, thyroid and blood sugar — and further tests or referral depend on the findings.

Watch: related videos

Examination and clinical videos from the MedicalVideos.com library relevant to this symptom. Some clinical footage is graphic — that is the nature of a medical video library.

▶ WatchLiving with chronic fatigue syndromeWatch on MedicalVideos.com ▶ WatchUsmle step 2 cs fatigueWatch on MedicalVideos.com ▶ WatchChronic fatigue syndrome diet and managementWatch on MedicalVideos.com

Related guides on MedicalVideos.com

Frequently asked questions

When is tiredness more than just tiredness?

When it lasts for weeks, is getting worse, or stops you doing normal things — and especially when it arrives with other symptoms such as weight loss, fever or breathlessness. That pattern is worth a proper check rather than just more rest.

Can blood tests find the cause?

Often they help: anaemia, thyroid problems, diabetes and vitamin deficiencies all show up on blood tests. Sometimes the tests are normal and the cause is a mix of sleep, stress and recovery from illness, which your clinician can help you work through.

Related symptoms — General & Whole-Body Symptoms

Chills Excessive sweating Excessive thirst Feeling cold all the time Feeling generally unwell (malaise)Fever

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Please note: This page is educational information about a symptom. A symptom alone cannot diagnose any condition, and the causes listed here are possibilities, not a diagnosis. If you are worried about a symptom — especially one that is new, severe, getting worse or not going away — please see your own clinician, who can examine you and arrange tests. In an emergency, call your local emergency number.