What is fatigue?

When you feel fatigued, you have no energy. Fatigue can be described as:

• feeling exhausted during your usual activities
• feeling exhausted after activities
• not having enough energy to start your usual activities

Fatigue is a very common complaint.

What symptoms are related to fatigue?

People sometimes describe fatigue as weakness, sleepiness or ‘feeling flat'.

Symptoms of fatigue include:

• feeling very tired
• a feeling of tiredness that does not get better with rest
• growing tired quickly after you start an activity

Fatigue can come on suddenly or gradually, and can be distressing.

What causes fatigue?

Fatigue can be a symptom of:

• stress
• anxiety
• depression
• grief

Infections that can cause fatigue include:

• the flu
• COVID-19
• glandular fever

Fatigue can also be a symptom of a physical condition such as:

• anaemia or iron deficiency
• sleep problems, such as insomnia or obstructive sleep apnoea
• some hormonal conditions, such as an underactive thyroid or diabetes
• cancer
• heart failure and some other heart conditions
• kidney disease
• some autoimmune conditions

Some medicines can cause fatigue.

Fatigue can also be caused by lifestyle factors, such as:

• excessive alcohol use
• other substance use
• lack of exercise
• poor diet

Sometimes, a cause is not found.

Chronic (ongoing) fatigue

It is possible for fatigue to become persistent (chronic):

• Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) is one cause of ongoing fatigue.
• Long COVID can cause fatigue that can last for months.
• It's also possible to have unexplained chronic fatigue with no obvious medical cause.

How is the cause of fatigue diagnosed?

To find out what is causing your fatigue, your doctor will ask you about your symptoms and do a full physical examination.

Your doctor will want to know:

• what your fatigue feels like and if it gets better with rest
• how long you have been feeling tired and how quickly your fatigue came on
• about your sleep
• whether you have other symptoms
• about your lifestyle — including diet, exercise, and if you drink alcohol or take other substances
• what medicines and other treatments you are taking

They will also ask about your general health.

Depending on your symptoms and examination, your doctor may recommend blood tests or imaging tests (x-rays or scans).

When should I see my doctor?

See your doctor if you have fatigue for more than 2 weeks and it is not getting better.

You should see your doctor sooner if you have fatigue:

• that is worrying you
• that is stopping you from doing things
• as well as other symptoms, such as weight loss

How is fatigue treated?

Treatment will depend on what that is causing your fatigue.

Self-care at home

It may help to try some general self-care tips:

• Try improving your sleep with healthy sleep habits.
• Eat a healthy diet with plenty of fresh fruit and vegetables. Avoid junk food, and try to cut down on or avoid alcohol and caffeine, since these may affect your sleep.
• Get regular physical activity to help improve your sleep and lessen fatigue.
• Try relaxation techniques for stress relief.

While self-care may help, make sure to see your doctor if you are feeling very tired or fatigued. You may have a condition that needs treatment.

What are the complications of fatigue?

Fatigue can put you at increased risk of problems at work such as:

• the ability to do tasks safely
• workplace accidents
• performance issues

It may also cause problems with driving safely.

Can fatigue be prevented?

Fatigue is a symptom of several conditions, so it is difficult to prevent.

Resources and Support

Talk to your doctor if you are feeling very tired all the time.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.