Hector Osorio 29 Jan 2019

Tiredness (also known as fatigue) is an extremely common problem. In fact, “why am I so tired?” was one of the most frequently searched questions of the last 2 years at Google. The answers can vary, since tiredness can come from a physiological or psychological condition. In this article we’ll discuss 10 of the main causes of fatigue.   

1. Lifestyle

Most people who complain about acute fatigue (lasting days or weeks) only need to change some elements about their lifestyle to fix the situation. By doing that, the feeling of tiredness should decrease in a short amount of time.

Some of the most problematic behaviors that lead to fatigue include:

  • Consuming energy drinks/caffeine several times every day.
  • Going to bed too late at night (>11 pm).
  • Insufficient sleep (<7 hours)
  • Poor dieting habits (especially in children)

2. Stress

Stress can be acute or chronic. Acute stress is simply a part of life and people face it every day in situations that range from being scared by a spider to being afraid for your life. Chronic stress is more problematic since it raises cortisol (stress hormone) levels for a long period of time.

Cortisol is a natural reagent of the human body, it has plenty of functions. However, if its serum levels are high, cortisol leads to increased awareness, insomnia and eventually fatigue. Normally this happens when people experience things like:

  • The death of a loved one.
  • Being the primary caregiver for a family member or loved one.
  • Financial problems.
  • Social problems.
  • Work-related burn out.

Overall, repeated or sustained exposure to stressful situations promotes a general lack of energy.

3. Anemia

Anemia is a condition characterized by a low number or abnormal shape of red blood cells. In some countries up to 10% of the population is at risk of developing some kind of anemia, mostly due to low levels of iron. Pregnant women are especially vulnerable to it. There are several types of anemia; however, the one caused by iron deficiency is the most commonly related to fatigue.

Iron deficiency is related to fatigue mainly because this ion is essential for oxygen transportation, ATP production (the main energy currency of the cell) and muscle function. People with this condition usually experience dizziness and get tired easily.

4. Sleep apnea

This condition involves blocking of the upper airways during sleep which leads to short periods where the person is not able to breathe. This can be caused by a number of factors like obesity, genetic disorders, kidney failure, etc.   

The lack of sleep and sudden shortage of oxygen eventually lead to general sleepiness and fatigue in most cases. So far, women have proved to be more vulnerable to this condition.

5. Underactive thyroid

The condition is also known as Hypothyroidism. It is characterized by a low production of important hormones. Since early symptoms are very common for many other diseases, people can spend many years without being diagnosed.

Usually, the symptoms include weight gain, depression, muscle ache, sensitivity to cold, dry skin and hair and of course, fatigue.

This condition can be treated with hormone therapy.

6. Coeliac disease

This is an autoimmune disease that causes severe damage to the small intestine after the ingestion of food with gluten. It manifests at different levels of severity and many people are left undiagnosed and suffer the consequences.

Fatigue is often linked to this disease; however, the reason for this is not well understood. Most patients report depression and fatigue at the moment of their diagnosis, so it may just be due to some psychological effect, but some studies seem to link fatigue with gluten-free diets. There’s still a lot to research about this topic.

7. Chronic fatigue syndrome

CFS is the name given to a condition in which doctors can’t find an explanation for the extreme fatigue experienced by a patient. Normally, CFS doesn’t improve with rest and can’t be diagnosed with a single test. Only a series of tests discarding possible causes tend to lead to this particular result.

CFS also affects memory, can cause headaches, muscle pain, enlarged lymph nodes, etc. At the moment there’re no answers to why some people develop this syndrome and others don’t.

Some of the potential triggers include:

  • Viral infections
  • Problems with regulation of the immune system
  • Hormonal problems

8. Diabetes

This is a common and irreversible metabolic disease characterized by high levels of glucose in blood and urine. Fatigue is common among people with diabetes; however, the reason why is still unknown. This particular area of knowledge remains underexplored.

Some think that diabetes-related fatigue is the result of the interaction of many factors, including: Diet, physical activity, psychology, hormones, inflammation, etc. At the moment no one knows .

9. Glandular fever

Also known as infectious mononucleosis, this infection is mostly seen in adolescents or adults who haven’t been infected with the Epstein-Barr virus before, people can be infected and show no symptoms for nearly 2 months. 

Although fever is the main symptom, fatigue is the one that lasts the longest (up to 6 months after the infection).

10. Depression

Depression is the term usually used when someone feels sad or anxious for an extended period of time. People that have been depressed for a long period of time (over 2 years) can develop feelings of tiredness as part of a particular form of depression called dysthymia.

However, in literature, is common to see depression as the consequence of chronic fatigue syndrome. People who live with the syndrome often spend very long periods of their lives without effective treatment of diagnosis, which leads to feelings of hopelessness and eventually depression.

There are plenty of other reasons for why you may feel tired all the time, for example, if you are fighting an infection, it often triggers what some call “sickness behavior”, which sometimes includes fatigue. Overall, any condition related to chronic inflammation has the potential to cause tiredness. Or it simply could be that you need to make dietary changes. Whatever the case, if you If you experience long periods of fatigue and are concerned, talk to your doctor.  

To search for the best healthcare providers worldwide, please use the Mya Care search engine.

About the Author:
Hector Osorio is a cell biologist, research assistant and science/health content writer. He loves complex topics related to life sciences like cancer, viral infections and aging. He graduated from Central University of Venezuela Faculty of Sciences and worked as a research assistant for the Center of Experimental Medicine of the Venezuelan Center for Scientific Research (IVIC) for 5 years.


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