What is fatigue?

Fatigue is a constant feeling of tiredness which can be physical, mental or a combination of both.  You may feel sleepy, unmotivated and lethargic.  It is not a medical condition on its own, however, it is a symptom of other medical conditions. Fatigue can be a normal feeling after a hard and stressful day of work.  However, if even after getting proper rest and adequate nutrition you still feel tired, you should visit your doctor’s office for further inquiry.  This is because there are many medical conditions which are associated with fatigue.  People may use different terms to describe fatigue, some of them are listless, lethargic, lack of energy, worn out, tired, exhausted, weary, feeling down or malaise.

Causes of fatigue

The causes of fatigue can be classified into lifestyle factors and health conditions:

• Lifestyle factors:

1. Excess physical activity
2. Lack of sleep
3. Obesity
4. Emotional stress
5. Lack of physical activity
6. Medications such as antidepressant and antihistamines amongst others
7. Alcohol abuse
8. High caffeine intake
9. Unhealthy eating habits

• Health conditions:

1. Chronic fatigue syndrome: This condition causes extreme fatigue which is not associated with any underlying medical conditions

2. Anaemia: this happens when your haemoglobin (the protein which carries oxygen in the blood) level is low, making you feel unusually tired and out of breath
3. Fibromyalgia: this disorder is characterized by general musculoskeletal pain which is often accompanied by fatigue
4. Sleep apnoea: In this condition, your breathing stops and start, disturbing your sleep without you noticing.  This result in tiredness even after a full night’s sleep
5. Chronic pain: this makes it difficult to rest properly which inevitably leads to fatigue
6. Thyroid disorders: hypothyroidism and hyperthyroidism may be accompanied by fatigue
7. Eating disorder: anorexia and bulimia are often associated with fatigue due to inappropriate nutrition and habits
8. Cold & flu
9. Cancer
10. Diabetes
11. Congestive heart failure
12. Chronic obstructive pulmonary disease (COPD)
13. Acute liver failure
14. Depression
15. Anxiety disorders
16. Multiple sclerosis
17. Inflammatory bowel disease (IBD)

Symptoms associated with fatigue

Fatigue is not a condition itself but a symptom of conditions as mentioned above.  It is very often associated with other symptoms and these are:

• Chronic sleepiness
• Headache
• Muscle pain

• Muscle weakness
• Irritability
• Poor judgement and decision-making

In addition, you should go to the hospital immediately if your fatigue is accompanied by the following symptoms:

• Severe headache
• Vomiting blood
• Chest pain
• Rectal bleeding
• Difficulty breathing
• Irregular heartbeat
• Feeling like you want to hurt yourself
• Severe abdominal pain

Diagnosis of fatigue

A thorough history taking by your doctor is the initial step in diagnosis fatigue and it includes:

• Other symptoms associated with the fatigue
• When did it start
• What makes it worse or better
• The nature of the fatigue
• Any source of stress
• Current medications

Your doctor will do some test to rule out any other medical conditions which may be causing your fatigue:

• Complete blood count: red blood cell, white blood cell and platelet count
• Electrolytes: chloride, potassium and sodium
• Glucose
• BUN/creatinine: to measure your kidney function
• TSH (thyroid stimulating hormone): to identify any thyroid disorders
• Ferritin, b12, folic acid and iron: this will indicate whether you are anaemic

• Erythrocyte Sedimentation Rate (ESR): this is a marker of inflammation in the body

Treatment of fatigue

Some lifestyle changes may be adopted to help reduce fatigue:

• Get enough sleep
• Avoid known cause of stress
• Stay hydrated
• Adopt a good and healthy eating habit
• Avoid over-demanding schedules
• Cut down caffeine
• Avoid alcohol, cigarettes and illicit drugs

Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a condition characterized by extreme tiredness which does not resolve by resting and cannot be explained by any underlying medical condition. 

Women are four times more susceptible in developing CFS than men.  In addition, people who are in their 40s and 50s are at increased risk too.  Other factors which may increase your risk of developing CFS are stress, environmental factors and genetic predisposition.

The specific cause of CFS is still not known, however, some viruses such as Epstein-Barr Virus (EBV) and rubella virus may contribute in developing CFS.  Other causes could be impaired immune system, stress and hormonal imbalances.

Symptoms of CFS includes excessive tiredness, chronic inability to fall asleep and maintain the sleep, memory loss, inability to concentrate, feeling tired even after a good night’s sleep, muscle pain and frequent headaches.

CFS is difficult to diagnose as other medical conditions often have similar symptoms.  In addition, no specific test can be done to diagnose it.  Your doctor will proceed by ruling out other conditions which may be causing your symptoms first to make the diagnosis.

The Centers for Disease Control and prevention (CDC) has set 2 criteria to diagnose CFS:

• Have chronic fatigue for at least 6 months excluding other medical conditions whose manifestations include fatigue
• Simultaneously have 4 or more of the following:

1. Impaired memory
2. Difficulty to concentrate
3. Post-exercise malaise
4. Muscle pain
5. Feeling tired even after a good night’s sleep
6. Joint pain without sign of inflammation (redness or swelling)
7. Sore throat
8. Headache
9. Tender cervical lymph nodes

The treatment of CFS includes lifestyle modifications (same as for fatigue above) and treating associated symptoms.  For example, if you are suffering from depression as well, your doctor will start an antidepressant therapy.

Outlook of fatigue

Fatigue on its own is not alarming. In the absence of any serious medical condition, fatigue can easily be managed. Most of the time, adopting a proper sleep hygiene, eating healthy and implementing some other lifestyle modifications can significantly improve your wellbeing. However, it is important to seek medical attention if it is accompanied with other symptoms or if persistent. Once your doctor will know the cause following proper investigations, appropriate treatment will then be given.

J. Alastair, I. and Simon, M., 2016. Davidson’s Essentials of Medicine. 2nd ed. London: ELSEVIER.

Parveen, K. and Michael, C., 2017. Kumar & Clarks Clinical Medicine. 9th ed. The Netherlands: ELSEVIER.