7 medical conditions that can make you feel tired

When should I see a doctor about tiredness and fatigue?

According to the NHS, unexplained tiredness is one of the most common reasons for people to see their doctor.¹ Tiredness can usually be banished after a few nights of good sleep, as well as by addressing some common physiological, physical and lifestyle causes such as dealing with stress, improving your diet and exercising more or less intensely.

If tiredness persists, especially if you have been feeling constantly tired for more than 4 weeks, then it's time to see your doctor, so they can diagnose or rule out a medical condition that could be causing you to feel tired all the time.

Some of the most common medical conditions that can cause you to feel tired and fatigued include:

Menopause
Anaemia
Underactive thyroid
Diabetes
Inflammatory bowel disease (IBD)
Sleep apnoea
Low testosterone

Below I take a look at each of these conditions and explain why they can cause tiredness and fatigue and how your doctor will rule out or diagnose these health issues.

1. Menopause

If you are a woman aged 45 and over, then your doctor may look to test your hormone levels. Fatigue is a common symptom of menopause, which typically starts between the ages of 45 and 55. According to our menopause expert, Eileen Durward, "the majority of women who go through the menopause will get this at some point or another. It's part and parcel of the whole process. However, some women might just get it now and again, but for other women, it can be totally debilitating."

Changing hormone levels during the menopause can lead to a wide variety of symptoms, including fatigue. As your hormone levels rise and fall during the traditional period from peri-menopause to menopause, your energy can become depleted as your body adapts and rebalances without the hormones that it's been used to.

Fluctuating hormones can also make it harder to sleep well, especially if you are experiencing night sweats, plus it can affect your mood, all of which can impact your energy levels at this time.

While your doctor can test your hormone levels to help determine if you are menopausal, the blood test is not always accurate. Other factors are often considered including how old you are and whether you are experiencing other symptoms such as irregular periods, hot flushes and night sweats.

However, low iron levels, low thyroid function and low vitamin D levels can all cause similar symptoms, so you should ask your doctor to test for these as well, to rule them out.

How to help fight fatigue during menopause

You can try our Menopause Support tablets which contain isoflavones, hibiscus, as well as magnesium, which can specifically help with tiredness and fatigue.

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I'd also recommend trying our fantastic Balance Mineral Drink. This contains magnesium, a vital mineral for energy during the menopause. It also contains zinc, potassium, calcium and vitamin D.

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Our menopause expert Eileen has lots more fatigue-busting tips in her article ‘My top 5 tips to beat menopausal fatigue’.

2. Anaemia

Anaemia affects roughly a third of the world's population, with half the cases being due to iron deficiency², which is known as iron-deficiency anaemia. Feeling very tired is one of the most common symptoms of iron deficiency.

Iron is needed to make haemoglobin, a protein in red blood cells that enables them to carry oxygen throughout your body, even helping your muscles to store oxygen so it can be used later. Therefore, if you are lacking in iron, less oxygen can reach your tissues which can deprive your body of the energy it needs, resulting in you feeling tired, weak and even short of breath.

Common causes of iron deficiency, which can lead to anaemia, include blood loss through heavy menstrual bleeding or wounds, lack of iron intake due to poor diet or restrictive diets, inflammatory bowel disease and increased blood supply demands during pregnancy.

To diagnose iron-deficiency anaemia, your doctor will consider your lifestyle and medical history, your symptoms such tiredness and paleness of skin and, if needed, order a full blood count (FBC) test to confirm if you're anaemic.

If anaemic, you'll likely be prescribed iron tablets and will be advised to eat more iron-rich foods including dark-green leafy vegetables such as spinach and kale, plus, meat, pulses and fortified foods such as cereals and bread.

3. Underactive Thyroid

One of the most common medical conditions that can result in constant tiredness is an underactive thyroid, also known as hypothyroidism. The thyroid gland produces hormones which primarily regulate the body's metabolism and digestive system.

However, when the thyroid gland is underactive, these hormones are not being produced as effectively, which is why weight gain, as well as fatigue, is extremely common with hypothyroidism. Feeling cold is another common sign of an underactive thyroid.

An underactive thyroid can be identified by a blood test to measure your hormones levels. It is treated by taking daily hormone tablets to provide the body with the hormones that the thyroid gland is struggling to produce.

4. Diabetes

Another medical condition which should be considered if you are constantly feeling tired is diabetes. In this instance the feelings of fatigue are most common or extreme after mealtimes.

According to Diabetes UK, two common reasons for tiredness or lethargy are having blood sugar levels that are either too high or too low. In both cases, tiredness is the result of having an imbalance between one's level of blood glucose and the amount or effectiveness of circulating insulin.³

Diabetes is a common condition with approximately 3.9 million people living with diabetes in the UK and, by 2025, it is estimated that 5 million people will have diabetes in the UK. There are two main types of diabetes – type 1 diabetes and type 2 diabetes. Type 2 diabetes is far more common than type 1. In the UK, around 90% of all adults with diabetes have type 2.⁴

As well as feeling tired all the time, other signs of diabetes include excessive thirst and hunger, frequent urination, weight loss or gain, cuts or wounds that heal slowly and blurred vision.

If you are worried that you may have diabetes, you should contact your doctor who will use blood tests, such as the fasting plasma glucose (FPG) test or the A1C test, to diagnose diabetes.

5. Inflammatory bowel disease (IBD)

IBD is a term used to describe two chronic (long-term) inflammatory conditions which affect your digestive tract: Crohn's disease and Ulcerative colitis.

Crohn's disease is an inflammatory disease of the intestines, commonly affecting the lower part of the small intestine and into the large bowel. On the other hand, ulcerative colitis is an inflammatory condition which affects the large intestine.

Although Crohn's disease and Ulcerative colitis are different conditions that affect different parts of the digestive tract, they share many of the same symptoms. Tiredness is one of the main symptoms, as well as diarrhoea, cramping pain in the abdomen, loss of appetite and anaemia.
According to Crohn's & Colitis UK, tiredness and fatigue can be due to the illnesses themselves, from the malabsorption of nutrients, including iron, which can result in anaemia, from the side effects of some of the drugs used for IBD or from a lack of sleep if you have to keep getting up at night with pain or diarrhoea.⁵

Our own Digestion expert and Nutritional Therapist, Ali Cullen, also advises that "significant weight loss and malnutrition is also likely, especially in Crohn's disease if the digestion and absorption of food is impaired due to damage and dysfunction of parts of the small intestine. This can impact your absorption of nutrients, which can greatly impact on your energy levels."

Crohn's & Colitis UK also advise that there is no one test to diagnose Crohn's Disease or Ulcerative Colitis and instead your symptoms, together with the results of endoscopies, biopsies, blood and stool tests, scans and X-rays, will all be considered. To reach the diagnosis often requires a team of specialists including gastroenterologists, pathologists and radiologists.

It can take time to confirm a diagnosis of IBD as it may be necessary to rule out a number of other conditions, such as irritable bowel syndrome, coeliac disease and infections of the bowel, first.⁶

6. Obstructive Sleep Apnoea

If you are feeling exhausted upon waking and experience extreme daytime fatigue, then it could be a sign of Obstructive Sleep Apnoea (OSA). This sleep disorder occurs when normal breathing whilst sleeping is interrupted for 10 seconds or more.

During these episodes, the walls of the throat relax and narrow causing a partial obstruction of the airways to the lungs, which can cause you to snore loudly. Other signs of sleep apnoea include noisy and laboured breathing and repeated short periods where breathing is interrupted by gasping or snorting.

When your breathing becomes shallow or hesitant, your body will attempt to pull you out of deep sleep and into light sleep or wakefulness in order to regulate your breathing. This can greatly impact the quality of your sleep, which can result in daytime tiredness or extreme fatigue if left undiagnosed.

In addition, an episode of sleep apnoea can cause a loud snore or snort which is likely to wake you up. This can happen more than ten times an hour, so it is clear why sufferers and their partners feel fatigued the next day.

Sleep apnoea can be difficult to diagnose as most of the symptoms will occur while you are sleeping and often go unnoticed or unrecognised, unless pointed out by someone such as your partner.

According to the NHS, it is more common in men than women and although sleep apnoea can occur at any age, it's more common in people who are over 40.

Menopause can also be a cause in women – the changes in hormone levels during the menopause may cause the throat muscles to relax more than usual.⁷ Other causes include being overweight, medication such as sleeping tablets and smoking.

It is important to consult your doctor immediately if you or someone else suspects you might have sleep apnoea, as it can be a potentially serious disorder which requires treatment. It's also believed that the long-term ramifications of undiagnosed sleep apnoea can be considerably damaging, as it can often lead to other health issues such as depression, diabetes, heart disease and high blood pressure.

7. Low testosterone

Lack of testosterone can cause a number of symptoms to arise, including fatigue and tiredness. Testosterone is the main male sex hormone, which rises during puberty then levels off once men reach their late teens. As a man gets older, usually between the ages of 40 and 70, the hormone can start to decline.

However the hormone does not rapidly decline in the way hormones do in women going through menopause, therefore many men do not tend to notice it. In some cases, however, testosterone levels begin to decline naturally by as early as the age of 30 making it more likely that, over time, symptoms such as fatigue can become noticeable.

If you are concerned about low testosterone levels then it is advisable to visit your GP. They may order a blood test to measure your hormone levels and if it turns out they are particularly low, your doctor may then refer you to an endocrinologist who specialises in hormone problems.

Our Men's Health advisor Dr. Jen Tan also advises that there is another condition which can cause men to experience tiredness as they age. He explains, "A common sign of an enlarged prostate is frequent night-time trips to the toilet, which can greatly disrupt sleep and result in daytime tiredness." An enlarged prostate, also known as BPH, is very common in older men, with 50% of those over 50 experiencing symptoms.⁸

Take our prostate symptom checker to see if you could have the condition. If you think this is the case, the next thing you should do is get the diagnosis confirmed by your doctor.

A diagnosis can be made on your medical history and symptoms. However, in order to exclude other causes of your symptoms, (including prostate cancer) an internal examination to assess the size of your prostate gland and blood tests may be required.

What other health issues could be causing you to feel tired?

Other health issues and conditions which your doctor may also consider if you are feeling tired all the time, and the above conditions have been ruled out, include chronic fatigue syndrome, fibromyalgia and heart disease.

It is also common to feel tired both during and after feeling unwell, as your body uses up its energy to fight infections and recover. However, one condition which can cause tiredness to linger is glandular fever. According to the NHS, fatigue is the most persistent symptom and often lasts a few weeks, although some people may feel persistently fatigued for several months after the other symptoms have passed.⁹

Furthermore, tiredness and fatigue can sometimes be a side effect of medications, such as anti-depressants, antihistamines, pain relievers and heart medicines.

If you are concerned about on-going tiredness and fatigue then it is very important to consult your doctor about it and not ignore it. While most instances of tiredness can be resolved after getting more sleep or improving your lifestyle, the above conditions represent instances where tiredness can persist long-term, therefore it is important to consult your doctor to rule out these conditions, especially if you have been experiencing on-going fatigue for over 4 weeks.