Chronic fatigue syndrome, also known as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), is a complex long-term condition that can significantly affect energy, concentration, sleep and everyday activities.

The fatigue associated with ME/CFS is different from ordinary tiredness. It can be severe, may not improve fully with rest and often becomes worse after physical or mental activity.

One of the most important features of the condition is post-exertional malaise (PEM), where symptoms worsen after even relatively small amounts of activity.

Symptoms can vary considerably between people. In addition, their severity may change from day to day.

What Are the Symptoms of ME/CFS?

Symptoms can affect several parts of the body.

Common symptoms include:

• severe and persistent fatigue
• post-exertional malaise
• unrefreshing sleep
• difficulty concentrating
• memory problems
• muscle pain
• joint pain
• headaches
• dizziness
• feeling faint when standing
• sensitivity to light, sound or temperature
• sore throat
• tender lymph nodes
• flu-like feelings
• difficulty tolerating physical or mental activity

Some people describe problems with concentration and memory as brain fog.

What Is Post-Exertional Malaise?

Post-exertional malaise, or PEM, is a worsening of symptoms following physical, mental or emotional effort.

Importantly, the activity that triggers PEM may be relatively minor. For example, a person may feel worse after:

• walking
• housework
• shopping
• working or studying
• attending a social event
• concentrating for a long period
• dealing with emotional stress

Symptoms may worsen immediately or several hours later. In some cases, the increase in symptoms can last for days or longer.

Because of this, managing activity carefully is an important part of living with ME/CFS.

What Causes Chronic Fatigue Syndrome?

Researchers do not yet fully understand the exact cause.

In some people, symptoms begin after an infection. However, ME/CFS can also develop without an obvious trigger.

Researchers continue to investigate possible roles for:

• immune system changes
• nervous system function
• energy metabolism
• hormonal regulation
• infections
• genetic susceptibility

The condition is not simply caused by being unfit, lacking motivation or experiencing ordinary tiredness.

Can ME/CFS Develop After an Infection?

Yes. Some people report that their symptoms began after a viral or other infectious illness.

Possible infections associated with the onset of prolonged fatigue include:

• glandular fever
• influenza-like illnesses
• COVID-19
• other viral infections

However, most people who develop these infections do not go on to develop ME/CFS.

Researchers are continuing to study why persistent symptoms develop in some people.

ME/CFS and Long COVID

ME/CFS and Long COVID can share several symptoms, including:

• severe fatigue
• post-exertional malaise
• brain fog
• sleep problems
• dizziness
• exercise intolerance

However, they are not necessarily the same condition.

People who develop persistent symptoms after COVID-19 should discuss them with a healthcare professional so other causes can be considered and an appropriate management plan can be developed.

How Is Chronic Fatigue Syndrome Diagnosed?

There is no single blood test, scan or other test that can confirm ME/CFS.

Instead, doctors usually diagnose the condition based on:

• symptoms
• how long symptoms have been present
• the effect on everyday activities
• medical history
• physical examination
• tests to rule out other possible causes

Your doctor may arrange blood or other tests because several medical conditions can cause persistent fatigue.

Other Causes of Persistent Fatigue

Fatigue is a common symptom and does not automatically mean someone has ME/CFS.

Other possible causes include:

• anaemia
• thyroid disorders
• vitamin deficiencies
• sleep disorders
• diabetes
• infections
• autoimmune conditions
• heart or lung disease
• medication side effects
• depression or anxiety
• other chronic illnesses

Therefore, appropriate medical assessment is important before attributing ongoing fatigue to chronic fatigue syndrome.

How Severe Can ME/CFS Be?

The condition can range from mild to very severe.

Mild

A person may still be able to work, study or manage everyday activities, but they may need to reduce other activities and spend more time resting.

Moderate

Daily activities may become substantially limited. People may need regular periods of rest and may find leaving home difficult.

Severe

People with severe symptoms may spend much of their time at home or in bed and may need help with everyday activities.

Very Severe

A very small number of people become extremely limited and may need significant assistance with personal care.

They may also become highly sensitive to light, noise or other stimulation.

Treatment and Management

There is currently no single treatment that cures ME/CFS.

Instead, management focuses on reducing symptoms, preventing unnecessary symptom flare-ups and improving quality of life.

Treatment should be tailored to the individual.

It may involve:

• activity management
• managing sleep problems
• treating pain
• managing dizziness
• addressing nutritional needs
• workplace or study adjustments
• psychological support where helpful
• treating other medical conditions

A healthcare professional can help develop a management plan based on your symptoms and abilities.

Activity Management and Pacing

Pacing involves balancing activity and rest to reduce the risk of triggering post-exertional malaise.

This may involve:

• breaking tasks into smaller steps
• resting before symptoms become severe
• alternating physical and mental activities
• planning demanding activities carefully
• reducing unnecessary exertion
• allowing adequate recovery time
• recognising personal limits

Keeping an activity and symptom diary may help identify patterns.

The aim is not to push through severe symptoms. Instead, pacing focuses on working within an individual’s current energy limits.

Exercise and ME/CFS

Physical activity needs to be approached carefully.

Because exertion can trigger post-exertional malaise, a standard exercise program that steadily increases activity regardless of symptoms may not be appropriate.

Instead, activity should be individualised and adjusted according to:

• symptom severity
• current abilities
• recovery after exertion
• personal limits

Some people may benefit from gentle movement within their tolerance, while others with severe symptoms may tolerate very little activity.

Discuss exercise or rehabilitation plans with a healthcare professional familiar with ME/CFS.

Sleep Problems

Many people experience unrefreshing or disturbed sleep.

Possible problems include:

• difficulty falling asleep
• waking frequently
• sleeping for long periods without feeling refreshed
• changes in sleep timing
• daytime sleepiness

Helpful sleep habits may include:

• maintaining a regular sleep schedule
• creating a quiet and comfortable sleep environment
• limiting caffeine later in the day
• reducing stimulating activities close to bedtime

However, sleep problems may require further assessment if they are persistent.

For more information, see our Insomnia guide.

Managing Pain

Muscle aches, joint pain and headaches can occur with ME/CFS.

Management may include:

• appropriate pain-relieving medicines
• heat or cold where suitable
• gentle positioning and stretching within tolerance
• addressing sleep problems
• reviewing activities that worsen symptoms

Your pharmacist can help you choose suitable over-the-counter pain relief and check whether it interacts with other medicines.

Persistent or severe pain should be discussed with your doctor.

Brain Fog and Concentration Problems

Cognitive symptoms can make it difficult to:

• concentrate
• remember information
• find words
• multitask
• read for long periods
• process information quickly

Helpful strategies may include:

• doing demanding tasks when you feel most alert
• taking regular breaks
• reducing distractions
• using reminders and calendars
• breaking complex tasks into smaller steps
• avoiding too many activities at once

Mental exertion can also trigger post-exertional malaise, so cognitive activity may need to be paced in the same way as physical activity.

Dizziness and Standing

Some people experience dizziness, rapid heartbeat or feeling faint when they stand.

These symptoms may relate to orthostatic intolerance, where the body has difficulty maintaining normal circulation while upright.

Helpful measures vary depending on the cause.

Therefore, speak with your doctor if you frequently experience:

• dizziness
• fainting
• racing heart
• weakness when standing
• symptoms that improve after lying down

Further assessment may be needed.

Diet and Nutrition

There is no specific diet proven to cure chronic fatigue syndrome.

However, a balanced diet can help support general health.

Try to include:

• vegetables
• fruit
• wholegrains
• adequate protein
• healthy fats
• enough fluids

People with severe symptoms may have difficulty shopping, preparing meals or eating enough.

In these situations, a dietitian may help develop practical strategies.

Be cautious with supplements promoted as cures for ME/CFS because evidence for many products is limited.

Vitamins and Supplements

Some people try vitamins, minerals or complementary medicines to manage fatigue.

However, supplements are unlikely to help unless a deficiency or specific nutritional need is present.

In addition, supplements can interact with prescription medicines.

Ask your doctor or pharmacist before starting high-dose vitamins, herbal products or other complementary treatments.

Mental Health and ME/CFS

Living with a long-term illness can affect emotional wellbeing.

People may experience:

• frustration
• isolation
• anxiety
• low mood
• grief over changes in their abilities

These feelings do not mean the physical condition is psychological.

However, counselling or psychological support may help some people cope with the impact of chronic illness.

For related information, see our Depression and Anxiety Disorders guides.

Work and Study

ME/CFS can make regular work or study difficult, particularly when symptoms fluctuate.

Helpful adjustments may include:

• reduced hours
• flexible schedules
• working from home
• additional rest breaks
• reducing physically demanding tasks
• quieter work or study environments
• extended deadlines
• spreading tasks across several days

A doctor or occupational therapist may help identify suitable adjustments.

Managing Flare-Ups

Symptoms may temporarily become worse after overexertion, illness, poor sleep or other triggers.

During a flare-up, it may help to:

• reduce activity
• prioritise essential tasks
• increase rest
• maintain hydration
• avoid trying to compensate by pushing harder
• gradually return to your usual level of activity as symptoms settle

Planning for flare-ups can make them easier to manage.

Can You Recover From ME/CFS?

The course of the condition varies considerably.

Some people improve substantially over time. Others experience ongoing symptoms or periods of improvement followed by relapse.

Recovery cannot be predicted accurately for an individual.

Therefore, management generally focuses on improving daily function and quality of life while avoiding activities that repeatedly worsen symptoms.

When Should You See a Doctor?

Arrange medical assessment if fatigue:

• is severe
• lasts for several weeks
• interferes with work, school or everyday activities
• occurs with unexplained weight loss
• occurs with persistent fever
• is associated with significant pain
• is accompanied by fainting or breathing problems
• becomes progressively worse
• has no obvious explanation

Persistent fatigue has many possible causes, so medical assessment is important.

For additional information about ME/CFS, see Healthdirect.

When Is Urgent Medical Care Needed?

Seek urgent medical attention if fatigue occurs with:

• severe difficulty breathing
• chest pain
• fainting
• sudden weakness
• confusion
• severe dehydration
• loss of consciousness
• rapidly worsening symptoms

Call 000 if symptoms are severe or life-threatening.

Support for People With ME/CFS

Living with a long-term condition can be challenging for both the person affected and their family.

Support may come from:

• GPs
• medical specialists
• physiotherapists familiar with ME/CFS
• occupational therapists
• dietitians
• psychologists or counsellors
• community support organisations

Emerge Australia provides Australian information and support for people living with ME/CFS and related conditions.

Speak With Your Pharmacist

Your MediAdvice pharmacist can help manage some symptoms associated with ME/CFS and review your medicines.

They can provide advice about:

• pain relief
• sleep-related medicines
• medicine side effects
• supplements
• potential medicine interactions

If fatigue is new, unexplained or becoming worse, your pharmacist may recommend that you see your GP for further assessment.

General advice only: This information is not intended to replace advice from your healthcare professional. Persistent or severe fatigue should be medically assessed, particularly if it is accompanied by other concerning symptoms.