Fatigue

Date Updated: 02/11/2023

Definition

Fatigue is a common symptom. Almost everyone feels it during short-term illness. Fortunately, fatigue usually goes away when the illness is over.

But sometimes fatigue doesn't go away. It doesn't get better with rest. And the cause might be unclear.

Fatigue reduces energy, the ability to do things and the ability to focus. Ongoing fatigue affects quality of life and state of mind.

Causes

Most of the time fatigue can be traced to one or more lifestyle issues, such as poor sleep habits or lack of exercise. Fatigue can be caused by a medicine or linked to depression. Sometimes fatigue is a symptom of an illness that needs treatment.

Lifestyle factors

Fatigue may be related to:

Alcohol or drug use
Eating poorly
Medicines, such as ones used to treat allergies or coughs
Not enough sleep
Too little physical activity
Too much physical activity

Conditions

Exhaustion that doesn't let up might be a sign of:

Adrenal insufficiency
Amyotrophic lateral sclerosis (ALS)
Anemia
Anxiety disorders
Cancer
Chronic fatigue syndrome
Chronic infection or inflammation
Chronic kidney disease
COPD
Coronavirus disease 2019 (COVID-19)
Depression (major depressive disorder) or other mood disorders
Diabetes
Fibromyalgia
Grief
Heart disease
Heart failure
Hepatitis A
Hepatitis B
Hepatitis C
HIV/AIDS
Hyperthyroidism (overactive thyroid)
Hypothyroidism (underactive thyroid)
Inflammatory bowel disease (IBD)
Liver disease
Low vitamin D
Lupus
Medicines and treatments, such as chemotherapy, radiation therapy, pain medicines, heart medicines and antidepressants
Mononucleosis
Multiple sclerosis
Obesity
Parkinson's disease
Physical or emotional abuse
Polymyalgia rheumatica
Pregnancy
Rheumatoid arthritis
Sleep apnea
Stress
Traumatic brain injury

When to see a doctor

Call 911 or your local emergency number

Get emergency help if you have fatigue and any of the following:

Chest pain.
Shortness of breath.
Irregular or fast heartbeat.
Feeling that you might pass out.
Severe stomach, pelvic or back pain.
Unusual bleeding, including bleeding from the rectum or vomiting blood.
Severe headache.

Seek help for urgent mental health problems

Get emergency help if your fatigue is related to a mental health problem and your symptoms also include thoughts of harming yourself or of suicide. Call 911 or your local emergency services number right away. Or contact a suicide hotline. In the U.S., call or text 988 to reach the 988 Suicide & Crisis Lifeline. Or use the Lifeline Chat.

Schedule a doctor's visit

Call for an appointment with a health care provider if resting, reducing stress, eating well and drinking plenty of fluids for two or more weeks hasn't helped your fatigue.