<unk>  <unk>  is the development of symptoms when standing upright that are relieved when reclining. There are many types of<unk> .<unk>  can be a subcategory of dysautonomia, a disorder of the autonomic nervous system occurring when an individual stands up. Some animal species with<unk>  blood pressure have evolved to cope with<unk>  disturbances. A substantial overlap is seen between syndromes of<unk>  on the one hand, and either chronic fatigue syndrome or fibromyalgia on the other. It affects more women than men (female-to-male ratio is at least 4:1), usually under the age of 35.<unk>  occurs in humans because standing upright is a fundamental stressor, so requires rapid and effective circulatory and neurologic compensations to maintain blood pressure, cerebral blood flow, and consciousness. When a human stands, about 750 ml of thoracic blood are abruptly translocated downward. People who suffer from<unk>  lack the basic mechanisms to compensate for this deficit. Changes in heart rate, blood pressure, and cerebral blood flow that produce<unk>  may be caused by abnormalities in the interactions between blood volume control, the cardiovascular system, the nervous system, and circulation control system.
Orthostatic intolerance
Hyperesthesia
Sarcopenia
Adynamia
Premastication
Exercise intolerance
Perfume intolerance
Carotidynia