What is fatigue?

Fatigue is the feeling of being tired all the time. It is different from the feeling of sleepiness you get at bedtime or tiredness after exercise or a late night. Fatigue may be physical (in your body) or psychological (in your mind). 

You are more likely to experience fatigue if you have a physical or mental illness or are on a low-income. Women are more commonly affected than men. 

What are the symptoms of fatigue?

Fatigue can cause a wide range of symptoms.

  • Physical: feeling tired all the time, headaches, lightheadedness, sore, aching or weak muscles, loss of appetite, prone to getting sick.
  • Mental: slowed reflexes and responses, poor decision making and judgement, short-term memory problems, poor concentration.
  • Emotional: moodiness, irritability, low motivation, feeling depressed and hopeless.

What causes fatigue?

Most of the time fatigue is not due to one thing, but a combination of psychological, physical and lifestyle factors. 


Psychological causes of fatigue are much more common than physical ones.  

It’s common to feel fatigued if you are experiencing:

  • Anxiety– for example, worrying about something so much that it keeps you up at night.
  • Grief or emotional shock – for example, after the death of a loved one or a natural disaster. 
  • Stress – including stress at work, juggling work and family commitments, low income, or even positive events, such as planning a wedding.
  • Depression – fatigue is a common symptom of depression. 


It is common to feel tired when you are:

  • underweight, overweight or obese
  • pregnant or breastfeeding
  • sick or have a health condition such as anaemia, thyroid problems, coeliac disease or diabetes.
  • having cancer treatment such as chemotherapy or radiotherapy
  • taking certain medications – some medications and some combinations of medications can make you feel tired. The tiredness may improve as your body gets used to the new medication or new combination of medications. If you think your medication is causing fatigue, talk to your doctor. They may reduce or change your medication.  


Fatigue can also be caused by lifestyle factors.

  • Drinking too much alcohol: Drinking alcohol in the evening tends to make you wake up in the middle of the night. Drinking too much on a regular basis can affect your mood and your sleep.
  • Having a disturbed sleep pattern: Going to sleep at the same time every night and waking up at the same time every morning helps set your body’s natural sleep-wake cycle.
  • Shift work, looking after small children or even just sleeping in on the weekend, can throw your normal sleep pattern off balance. This means your body wants to be sleeping at times when you need to be awake.
  • Drinking too much caffeine: Caffeine is a stimulant that can stress the nervous system and cause insomnia.
  • Not exercising regularlyKeeping active every day is one of the best things you can do to reduce stress and anxiety, help you sleep better and improve your sense of well-being. It seems counter-intuitive, but tiring yourself out with exercise means you’re less likely to feel fatigued.
  • Poor diet: Foods high in sugar provide a short-term energy boost that quickly wears off, making you feel more tired.  A healthy, balanced diet provides your body with the energy and nutrients it needs to function at its best. 

When should I see a doctor about tiredness? 

Tiredness + other symptoms

See your doctor if you have fatigue plus any of the following symptoms:

These may be signs of an underlying medical problem. 

Tiredness as main symptom

If tiredness is your main symptom, and you are getting enough exercise and sleep, eating a balanced diet and have a low-stress lifestyle and are still experiencing fatigue, see your doctor for a check-up. See also our separate page on chronic fatigue syndrome.

Questions a doctor may ask include the following:

  • Do you feel drowsy or weak?
  • Do you feel down or depressed?
  • Has your fatigue developed slowly or suddenly?
  • Is it cyclical or constant?
  • What do you think the cause might be?
  • Have you experienced any significant life events recently?
  • Is your life in balance? Consider work, relationships, physical, emotional, social, sense of worth and recreation.

Your doctor may also:

  • take your sleep history, including how much sleep you get each night, what the quality of your sleep is like, and whether you snore, wake or stop breathing in the night
  • do a physical examination to check for signs of illness or disease
  • carry out tests to rule out physical causes, such as blood and urine tests. 

What is the treatment for fatigue?

If you have a medical condition causing fatigue, treatment will focus on the condition. If there is no medical cause, treatment will focus on lifestyle factors. 

Talking therapy (counselling) may be useful if you:

  • are worried or anxious
  • have experienced a major life event
  • are feeling low or depressed.

source :https://www.healthnavigator.org.nz/health-a-z/t/tiredness-fatigue/