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[[Physical]] fatigue or muscle weakness (or "lack of [[strength]]") is a direct term for the inability to exert [[force]] with one's muscles to the [[degree]] that would be [[expected]] given the [[individual]]'s general physical fitness.

[[Physical]] fatigue or muscle weakness (or "lack of [[strength]]") is a direct term for the inability to exert [[force]] with one's muscles to the [[degree]] that would be [[expected]] given the [[individual]]'s general physical fitness.

A test of [[strength]] is often used during a [[diagnosis]] of a muscular disorder before the [http://en.wikipedia.org/wiki/Etiology etiology] can be identified. Such [http://en.wikipedia.org/wiki/Etiology etiology] depends on the [[type]] of muscle weakness, which can be true or [[perceived]] as well as [[central]] or [[peripheral]]. True weakness is substantial, while perceived rather is a sensation of having to put more [[effort]] to do the same task. On the other hand, central muscle weakness is an overall exhaustion of the whole [[body]], while [[peripheral]] weakness is an exhaustion of [[individual]] muscles.

A test of [[strength]] is often used during a [[diagnosis]] of a muscular disorder before the [https://en.wikipedia.org/wiki/Etiology etiology] can be identified. Such [https://en.wikipedia.org/wiki/Etiology etiology] depends on the [[type]] of muscle weakness, which can be true or [[perceived]] as well as [[central]] or [[peripheral]]. True weakness is substantial, while perceived rather is a sensation of having to put more [[effort]] to do the same task. On the other hand, central muscle weakness is an overall exhaustion of the whole [[body]], while [[peripheral]] weakness is an exhaustion of [[individual]] muscles.

===Mental fatigue===

===Mental fatigue===

In addition to [[physical]], fatigue also includes [[mental]] fatigue, not necessarily including any muscle fatigue. Such a mental fatigue, in turn, can [[manifest]] itself both as [http://en.wikipedia.org/wiki/Somnolence somnolence] (decreased wakefulness) or just as a general decrease of [[attention]], not necessarily including sleepiness. It may also be described as a more or less decreased level of [[consciousness]]. In any case, this can be dangerous when [[performing]] tasks that require constant [[concentration]], such as driving a vehicle. For instance, a [[person]] who is sufficiently somnolent may [[experience]] [http://en.wikipedia.org/wiki/Microsleep microsleeps]. However, objective [[cognitive]] testing should be done to [[differentiate]] the neurocognitive deficits of brain disease from those attributable to tiredness.

In addition to [[physical]], fatigue also includes [[mental]] fatigue, not necessarily including any muscle fatigue. Such a mental fatigue, in turn, can [[manifest]] itself both as [https://en.wikipedia.org/wiki/Somnolence somnolence] (decreased wakefulness) or just as a general decrease of [[attention]], not necessarily including sleepiness. It may also be described as a more or less decreased level of [[consciousness]]. In any case, this can be dangerous when [[performing]] tasks that require constant [[concentration]], such as driving a vehicle. For instance, a [[person]] who is sufficiently somnolent may [[experience]] [https://en.wikipedia.org/wiki/Microsleep microsleeps]. However, objective [[cognitive]] testing should be done to [[differentiate]] the neurocognitive deficits of brain disease from those attributable to tiredness.

==Differential diagnosis==

==Differential diagnosis==

The [[majority]] of people who have fatigue do not have an underlying cause [[discovered]] after a year with the condition. In those who do have a possible diagnosis musculoskeletal (19.4%) and [[psychological]] problems (16.5%) are the most common. Definitive physical conditions were only found in 8.2%.[5]

The [[majority]] of people who have fatigue do not have an underlying cause [[discovered]] after a year with the condition. In those who do have a possible diagnosis musculoskeletal (19.4%) and [[psychological]] problems (16.5%) are the most common. Definitive physical conditions were only found in 8.2%.[5]

Fatigue is typically the result of [[working]], mental [[stress]], overstimulation and understimulation, jet lag or [[active]] [[recreation]], [[depression]], and also boredom, disease and lack of [[sleep]]. It may also have [[chemical]] causes, such as [[poisoning]] or [http://en.wikipedia.org/wiki/Mineral mineral] or [http://en.wikipedia.org/wiki/Vitamin vitamin] deficiencies. Massive blood loss frequently results in fatigue. Fatigue is [[different]] from drowsiness, where a patient feels that [[sleep]] is required. Fatigue is a [[normal]] [[response]] to [[physical]] exertion or [[stress]], but can also be a sign of a physical disorder.

Fatigue is typically the result of [[working]], mental [[stress]], overstimulation and understimulation, jet lag or [[active]] [[recreation]], [[depression]], and also boredom, disease and lack of [[sleep]]. It may also have [[chemical]] causes, such as [[poisoning]] or [https://en.wikipedia.org/wiki/Mineral mineral] or [https://en.wikipedia.org/wiki/Vitamin vitamin] deficiencies. Massive blood loss frequently results in fatigue. Fatigue is [[different]] from drowsiness, where a patient feels that [[sleep]] is required. Fatigue is a [[normal]] [[response]] to [[physical]] exertion or [[stress]], but can also be a sign of a physical disorder.

The sense of fatigue is [[believed]] to [[originate]] in the [http://en.wikipedia.org/wiki/Reticular_activating_system reticular activating system] of the lower [[brain]]. [http://en.wikipedia.org/wiki/Musculoskeletal_system Musculoskeletal] [[structures]] may have co-evolved with appropriate brain structures so that the complete [[unit]] functions [[together]] in a constructive and adaptive fashion. The entire [[systems]] of muscles, joints, and [http://en.wikipedia.org/wiki/Proprioception proprioceptive] and [http://en.wiktionary.org/wiki/kinesthetic kinesthetic] [[functions]] plus parts of the brain evolve and function together in a unitary way.

The sense of fatigue is [[believed]] to [[originate]] in the [https://en.wikipedia.org/wiki/Reticular_activating_system reticular activating system] of the lower [[brain]]. [https://en.wikipedia.org/wiki/Musculoskeletal_system Musculoskeletal] [[structures]] may have co-evolved with appropriate brain structures so that the complete [[unit]] functions [[together]] in a constructive and adaptive fashion. The entire [[systems]] of muscles, joints, and [https://en.wikipedia.org/wiki/Proprioception proprioceptive] and [https://en.wiktionary.org/wiki/kinesthetic kinesthetic] [[functions]] plus parts of the brain evolve and function together in a unitary way.

Temporary fatigue is likely to be a minor illness like the [http://en.wikipedia.org/wiki/Common_cold common cold] as one part of the sickness [[behavior]] [[response]] that happens when the [http://en.wikipedia.org/wiki/Immune_system immune system] fights an infection. Chronic fatigue, on the other hand, [[meaning]] of six months or more duration, is a symptom of a large number of different diseases or conditions.  

Temporary fatigue is likely to be a minor illness like the [https://en.wikipedia.org/wiki/Common_cold common cold] as one part of the sickness [[behavior]] [[response]] that happens when the [https://en.wikipedia.org/wiki/Immune_system immune system] fights an infection. Chronic fatigue, on the other hand, [[meaning]] of six months or more duration, is a symptom of a large number of different diseases or conditions.  

==Exams and Tests==

==Exams and Tests==

After [[deciding]] to see a doctor for [[guidance]] and treatment against fatigue, the physician will look at a [[person]]'s medical [[history]] along with the [[evaluation]] of the fatigue itself. When evaluating [[sleep]], questions will be asked regarding the [[quality]] of sleep, [[emotional]] [[state]] of the [[person]], sleep [[pattern]], and [[stress]] level. Questions about a person's diet, [[exercise]] level, and the symptoms that they are [[experiencing]] will also be asked. The quality of sleep a person is receiving is important. Certain points like if there is a [[pattern]] of fatigue consistent with the same time of the day or if it [[progressively]] worsens throughout the day are looked at. It is important that a patient take note of specific areas of [[sleep]] and fatigue before the visit so that they have answers to the right questions. The amount of sleep, the hours that are set aside for sleep, and the number of times that a [[person]] awakes during the night are important. Other tests that might be ordered by the physician include [http://en.wikipedia.org/wiki/Blood_test blood tests] to check for infection or anemia, [http://en.wikipedia.org/wiki/Urinalysis urinalysis] to look for signs of [http://en.wikipedia.org/wiki/Liver liver] disease or diabetes, and tests to monitor the function of the [http://en.wikipedia.org/wiki/Thyroid thyroid]. A common exam that monitors the levels of [[seven]] common substances found circulating in the blood is also used. It consists of the four electrolytes:sodium, potassium, chloride, and bicarbonate, along with two waste products of [http://en.wikipedia.org/wiki/Metabolism metabolism] (cleared by [[normally]] functioning kidneys) which are BUN and [http://en.wikipedia.org/wiki/Creatine creatine], and lastly, the source of [[energy]] for your body's cells, [http://en.wikipedia.org/wiki/Glucose glucose]. Specific tests will be run to check for [[HIV]] and female patients will also be required to receive a pregnancy test.

After [[deciding]] to see a doctor for [[guidance]] and treatment against fatigue, the physician will look at a [[person]]'s medical [[history]] along with the [[evaluation]] of the fatigue itself. When evaluating [[sleep]], questions will be asked regarding the [[quality]] of sleep, [[emotional]] [[state]] of the [[person]], sleep [[pattern]], and [[stress]] level. Questions about a person's diet, [[exercise]] level, and the symptoms that they are [[experiencing]] will also be asked. The quality of sleep a person is receiving is important. Certain points like if there is a [[pattern]] of fatigue consistent with the same time of the day or if it [[progressively]] worsens throughout the day are looked at. It is important that a patient take note of specific areas of [[sleep]] and fatigue before the visit so that they have answers to the right questions. The amount of sleep, the hours that are set aside for sleep, and the number of times that a [[person]] awakes during the night are important. Other tests that might be ordered by the physician include [https://en.wikipedia.org/wiki/Blood_test blood tests] to check for infection or anemia, [https://en.wikipedia.org/wiki/Urinalysis urinalysis] to look for signs of [https://en.wikipedia.org/wiki/Liver liver] disease or diabetes, and tests to monitor the function of the [https://en.wikipedia.org/wiki/Thyroid thyroid]. A common exam that monitors the levels of [[seven]] common substances found circulating in the blood is also used. It consists of the four electrolytes:sodium, potassium, chloride, and bicarbonate, along with two waste products of [https://en.wikipedia.org/wiki/Metabolism metabolism] (cleared by [[normally]] functioning kidneys) which are BUN and [https://en.wikipedia.org/wiki/Creatine creatine], and lastly, the source of [[energy]] for your body's cells, [https://en.wikipedia.org/wiki/Glucose glucose]. Specific tests will be run to check for [[HIV]] and female patients will also be required to receive a pregnancy test.

==See also==

==See also==

*[[Lassitude]]

*[[Lassitude]]

==External links==

==External links==

* [http://www.cancer.gov/cancertopics/pdq/supportivecare/fatigue/patient Fatigue — Information for Patients], U.S. National Cancer Institute

* [https://www.cancer.gov/cancertopics/pdq/supportivecare/fatigue/patient Fatigue — Information for Patients], U.S. National Cancer Institute

* [http://www.rcpsych.ac.uk/mentalhealthinfo/problems/sleepproblems/tiredness.aspx Tiredness] — Information leaflet from mental health charity The Royal College of Psychiatrists

* [https://www.rcpsych.ac.uk/mentalhealthinfo/problems/sleepproblems/tiredness.aspx Tiredness] — Information leaflet from mental health charity The Royal College of Psychiatrists

[[Category: Health]]

[[Category: Health]]