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Fatigue: Definition, Statistics, Causes & Treatment 

Fatigue Statistics

Fatigue or tiredness is a common condition that is mostly overlooked by people and healthcare providers. According to the statistics provided by Jason et al., in 2019 about 13.16% per 100,000 people per year suffer from fatigue indicating the increasing prevalence over the past five years as this prevalence rate of fatigue was 9.28% per 100,000 people per year in 2014. Therefore, it is important to understand what is fatigue or tiredness, its causes, and potential treatments [1].  

What is Fatigue?

Fatigue can be defined as the decrease in the muscular ability to function properly especially for long hours or longer periods of time. This is primarily due to the muscle weakness due to which ha person feels down and drowsy and lack of energy to perform certain tasks. Some researchers have compared fatigue with tiredness because the most obvious symptom of fatigue is feeling tired most of the time or when a person performs any task for a longer period of time [1].

Causes of Fatigue

There are various causes and reasons of fatigue and diagnosing the potential cause of fatigue is important so that corresponding treatment intervention can be adopted to treat fatigue.

  1. Hormonal Imbalance

Hormones play a key role in maintaining the regulation of energy levels and muscular activities. The thyroid hormones and adrenal gland hormones should be maintained so that the systems of the body may function properly. Deficiency of T3 and T4 thyroid hormones can cause fatigue as they regulate heart rate, body temperature, weight, and metabolism rate that produces energy content to perform muscular activities. Most of the time, physicians recommend checking the TSH hormone and overlooking the possible deficiency of T3 and T4 that can be a cause of fatigue [2].

Adrenal gland hormones such as pregnenolone, DHEA, testosterone, estrogen, and progesterone play a significant role in providing energy that prevents fatigue. However, common lab diagnostics are based on the determination of testosterone, estrogen, and progesterone levels but pregnenolone and DHEA are usually overlooked that are also important causes of fatigue as these are required for the production of other adrenal hormones [2].

  1. Vitamins Deficiency

 There are 13 vitamins that are essential for a human body to function properly and deficiency in any one of these vitamins can cause fatigue and tiredness. For instance, B vitamins including B1, B2, B3, B6, B7, and B12 are important in regulating the food conversion into energy at the cellular level. This energy production by the vitamins contributes to the prevention of fatigue. Similarly, vitamin D and vitamin C helps in strengthening bones and joints that also prevent fatigue [3].  

  1. Minerals Deficiency

According to Reinertsen et al., a human requires at least 16 essential minerals that play a significant role in regulating the functions and systems of the body. This may include magnesium, iron, iodine, selenium, zinc, calcium, sodium, potassium, and others. Adequate levels of these minerals help in the prevention of fatigue as a deficiency in one or more minerals can cause chronic fatigue or tiredness. Especially, if a person has magnesium, iodine, selenium, or zinc deficiency, the probability of fatigue is increased by up to 30% depending on the level of deficiency [3].

  1. Imbalanced Diet

Food is the primary source of energy that prevents fatigue and tiredness as it provides energy to the body to function properly. However, there are certain food items that only give the feeling of a full stomach but do not provide essential vitamins, minerals, and other nutrients to the body. For instance, the redefined carbohydrate-based foods (junk food), artificial sweeteners, and processed foods lack the nutrients and excessive intake of these foods can cause vitamins and minerals deficiencies that ultimately cause fatigue. Moreover, Twomey et al suggested that prolonged use of alcohol can also produce fatigue because it interacts with the nervous system due to which the brain is unable to send signals to absorb sufficient nutrients from the food resulting in chronic fatigue [4].

  1. Medications

There are various medications that inhibit the absorption of nutrients or the production of energy necessary for the muscles to function properly. This may include ACE inhibitors, anti-acids, antispasmodic, beta-blockers, anti-seizure, arthritis, autoimmune medicines, and blood thinners that may cause excessive fatigue due to their interaction with either the nervous system or digestive system. On the other hand, the treatment of life-long diseases such as diabetes, cholesterol, cardiovascular, and blood pressure is based on the prolonged use of medicines that can cause fatigue. Similarly, the treatment of cancer through opioids, chemotherapy, and radiation also results in chronic fatigue because these medicines directly interact at the cellular level restricting the energy production in the cells [5].

  1. Toxins

Toxins are those chemicals that negatively interact in the body either at the cellular level or at the organ level as mercury can cause fatigue as it is deposited in the muscles and bones due to which they are unable to produce sufficient energy required for the body. Moreover, other toxins such as arsenic, lead, toluene, lithium, and mold can also increase toxicity in the blood due to which the systems are negatively impacted and result in fatigue [5].

Treatment For Fatigue

To treat fatigue, the first step is to rule out the fundamental cause of fatigue such that if the primary cause of fatigue is vitamins, minerals, or hormonal imbalance, then the treatment would address the imbalance. Similarly, if the root cause of fatigue is vitamin or minerals deficiency, then the supplements would be provided to restore the specific deficiency. If a person is fatigued due to the intake of a combination of medicines, then the physician may change the combination of medicines that can prevent or lower the fatigue level [6].

Another approach to rule out the root cause and treatment of fatigue is to visit Ask ASTR that is an online platform to provide guidance related to fatigue and tiredness.

Also, you can schedule a Telehealth evaluation with one of our functional medicine doctors to figure out the root cause of your issue.


  1. Jason LA, Evans M, Brown M, Porter N. What is fatigue? Pathological and nonpathological fatigue. PM&R. 2010 May 1;2(5):327-31.
  2. Joyner MJ. Fatigue: Where Did We Come from and How Did We Get Here?. Medicine and science in sports and exercise. 2016 Nov 1;48(11):2224-7.
  3. Reinertsen KV, Loge JH, Brekke M, Kiserud CE. Chronic fatigue in adult cancer survivors. Tidsskrift for Den norske legeforening. 2017 Nov 13.
  4. Twomey R, Aboodarda SJ, Kruger R, Culos-Reed SN, Temesi J, Millet GY. Neuromuscular fatigue during exercise: Methodological considerations, etiology and potential role in chronic fatigue. Neurophysiologie Clinique/Clinical Neurophysiology. 2017 Apr 1;47(2):95-110.
  5. Harsevoort AG, Gooijer K, van Dijk FS, van der Grijn DA, Franken AA, Dommisse AM, Janus GJ. Fatigue in adults with Osteogenesis Imperfecta. BMC musculoskeletal disorders. 2020 Dec;21(1):1-6.
  6. Enoka RM, Duchateau J. Muscle fatigue: what, why and how it influences muscle function. The Journal of physiology. 2008 Jan 1;586(1):11-23.

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