Fatigue is a feeling of tiredness that doesn’t go away after getting plenty of rest. If it persists for a long time, it can be an indication of a serious condition.

  • One of the most common complaints in general practice
  • Causes can be both physical and psychological
  • Resolved by identifying the underlying condition and treating it

If fatigue becomes a continuous issue, you may want to contact a doctor to talk about your symptoms. Our GMC-registered clinicians are available to consult through our online video consultation service. You can book an appointment to speak to them between 9.30am and 4.30pm, five days a week.

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Possible causes

What causes fatigue?

There are several reasons why someone might feel fatigued. Often, it’s due to lifestyle circumstances. But if feelings of fatigue are severe or persist despite plenty of rest, it may be a sign of an underlying problem.

Lifestyle causes

It’s very common to feel fatigued as a consequence of a variety of activities. Being busy and trying to cram too much into a day can often lead to tiredness. Some possible factors that can cause fatigue include:

  • working too many hours
  • eating unhealthily
  • drinking alcohol excessively or taking recreational drugs
  • undergoing big changes in life such as moving house or changing jobs
  • or exercising too much or not enough.

Physical causes

Fatigue can often be the cause of a medical condition, such as:

  • a lack of iron in the blood (anaemia)
  • diabetes
  • an underactive thyroid (hypothyroidism)
  • a viral infection such as glandular fever
  • sleep apnoea
  • a vitamin deficiency
  • a side effect of medications such as antidepressants
  • or bowel conditions such as Crohn’s, ulcerative colitis or coeliac disease.

Most of these conditions will have other symptoms as well as tiredness, but it’s also possible that anaemia and hypothyroidism can have fatigue as the sole symptom.

Psychological causes

Fatigue can often be linked to psychological causes rather than physical causes. The following conditions are examples of psychological or emotional factors that can lead to fatigue

  • Depression: issues with sleep are often a common symptom of depression, and lacking energy to perform activities is also common.
  • Anxiety: being worried and feeling irritable about certain situations can take its toll on the body.
  • Eating disorders: on a physical level, these can affect your calorie and nutrient intake, and affect energy levels. But people with eating disorders may also feel anxious, which in itself can lead to fatigue.
  • Stress 
  • Boredom 
  • Bereavement 

Diagnosing the cause of fatigue

In order to try and find the cause of fatigue, a doctor will initially look to establish if there are other symptoms present, or if fatigue is the sole symptom. They will ask detailed questions about your medical history, before conducting a physical examination and possibly performing some tests.

A clinician is likely to ask questions focusing on the three areas of physical, psychological and lifestyle causes. They may ask whether you have recently lost any weight, whether your sleeping patterns and bowel habits have changed, and whether you have recently changed medication or dosages.

A doctor will also seek to determine what the nature of the tiredness is. For example, they may ask: 

  • is it physical exhaustion or mental exhaustion? 
  • how long has it persisted? 
  • when does it present itself: throughout the day or just towards the end? 
  • has it been triggered by an illness?

To establish potential mental and lifestyle causes, a doctor will most likely ask about your mood (whether you are worried or stressed about anything) and also whether you are eating in larger or smaller quantities. They may also ask how well you are sleeping, and whether you have been drinking more alcohol than usual, or taking recreational drugs.

For a physical examination, a doctor may check your pulse. A fast heart rate may be indicative of anxiety and stress. They may also weigh you, as drastic changes can sometimes indicate an underlying condition. A doctor may check your lymph glands for indications of glandular fever, and the thyroid gland. They are also likely to assess whether your joints are swollen or inflamed, and whether your eyes are showing any signs of anaemia.

A doctor may want to conduct tests, depending on what your medical history and physical examination has already revealed. If a doctor suspects that anaemia, coeliac disease, diabetes or a thyroid problem is the cause, they will order a full blood count test. There are other possible investigations they might do for problems related to fatigue, including liver function tests for suspected alcohol abuse and urinalysis for suspected diabetes.

If you feel as though you are constantly fatigued and would like to speak to a doctor online, our service can help. Our clinicians are available to consult with via our online video consultation service, with appointments available between 9.30am and 4.30pm, Monday to Friday. They can provide advice on your symptoms and issue prescriptions and referrals to specialists, where suitable. 

Page last reviewed:  02/09/2020
Types of Treatment

How is fatigue treated?

Treatment for fatigue depends on what the underlying cause is. Some causes will only require lifestyle adjustments, whereas others may need a long-term treatment plan.

There is no specific treatment that can be given for a complaint of fatigue in itself. However, if an underlying condition is causing tiredness, this can be addressed through treatment. For example, anaemia requires iron supplements. These help to improve levels of iron in the blood and this can help to address tiredness. If you are diagnosed with an underactive thyroid, there are treatments you can be given which act as a hormone replacement therapy, and these will help you to feel more energetic.

If the diagnosis is related to a vitamin deficiency, a doctor can prescribe vitamin tablets which can be taken with a meal. Coeliac disease is treated by eliminating wheat from your diet. Type 1 diabetes can be treated with insulin therapy, whereas type 2 diabetes can be treated with medicines such as metformin, which help to increase the body’s receptiveness to insulin. 

Many psychological conditions which cause fatigue can be helped through cognitive behavioural therapy or alternative talking treatments. They involve talking to a therapist about ways in which you can alter your behaviour, in order to combat the condition. It’s a widely-used treatment option for depression, anxiety and eating disorders. Antidepressants can also be prescribed for depression, although a common side effect of these is fatigue; so if your fatigue becomes worse on a certain medicine, a doctor may need to discuss alternatives with you.

What you can do to help fatigue

There are also many lifestyle adjustments which can help to alleviate fatigue. Establishing a sleeping pattern is important if you are struggling to sleep at night. This involves going to bed and getting up at regular times , and making sure the sleeping environment is comfortable.

To help deal with anxiety and stress, it can be helpful to take time every day to try and relax. If you have a particularly challenging job or are working too many hours, it may be worth trying to cut down your hours or speaking to your line manager about your responsibilities. Regular exercise is vital for dealing with fatigue, as it helps to stimulate the body and can significantly improve sleep. 

Speaking to a doctor can help if you feel constantly fatigued, but aren’t sure why. They will be able to help identify any underlying issues that may be causing it.  You can speak to a GMC-registered clinician online via our online video consultation service. Appointments are available from 9.30am to 4.30pm, five days a week.  

Page last reviewed:  02/09/2020
Questions and Answers

How long is it normal to be fatigued for?

It is very common to feel tired at some point daily. It is a natural bodily reaction to normal physical and mental exertion throughout the day. But usually, this feeling will go away after a period of rest. If it doesn’t, this is known as fatigue.

If the cause of fatigue is a chronic condition, then the feeling may come and go intermittently over long periods. If a temporary condition such as a viral infection is responsible, these tend to be self-limiting, and fatigue will dissipate once the infection has been cleared.

Is fatigue serious?

If fatigue is persistent, it might be an indication of a serious condition. Many mental disorders have fatigue as one of the main symptoms. However, sporadic fatigue will rarely be an indication of a serious physical condition, and is much more likely to be caused by daily life.

Can I get treatment for fatigue?

Treatment for fatigue is focused on addressing the underlying condition. 

For example, anaemia can be treated with iron supplements, and an underactive thyroid is treated with hormone replacement therapy. 

Lifestyle adjustments can have a significant impact on coping with fatigue. Regularly exercising and establishing a regular sleeping pattern are a couple of ways you can reduce fatigue.

How can I prevent fatigue?

Fatigue cannot always be prevented if it is due to a physical medical condition. 

If your routine or lifestyle is the cause of fatigue, there are a few ways to prevent it from becoming an issue in daily life. Eating sufficiently and healthily for consistent energy throughout the day is vital, as is exercising regularly and avoiding drinking too much alcohol.

Can I speak to a doctor about fatigue?

Yes. Our GMC-registered clinicians are available to consult with between 9.30am and 4.30pm, Monday to Friday. They can offer advice, prescriptions for treatment and referral to specialists, where appropriate. 

Page last reviewed:  02/09/2020

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