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Decrease of normal tonicity or tension, especially diminution of intraocular pressure or of muscle tone.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(hypotension), the lowering of tone (tension) of a tissue, organ, or system. The term “hypotonia” is most often used to denote a lowering of blood pressure below 105/65 mm Hg (14/8.7 kilonewtons per sq m) for men and 96/60 mm Hg (13.2/8 kilonewtons per sq m) for women, as a result of the lowering of the tone of the cardiovascular system. There are several forms of vascular hypotonia.

The physiological or adaptive form of hypotonia is found in many people, including those in physical training, athletes, and inhabitants of southern regions. The drop in arterial pressure is not accompanied by any symptoms of disease and is completely compensated for by the hemodynamic processes. Special treatment is not needed. Symptomatic hypotonia is one of the symptoms of a number of diseases, including many infectious diseases, tuberculosis, tumors, and some heart ailments. Treatment is directed at the removal of the basic disease. Primary or neurocirculatory hypotonia develops as an independent pathological process resulting from harmful effects on the neurohumoral system, which regulates vascular tone. (Among the factors that may adversely affect the neurohumoral system are negative emotions, strain on the nervous system as a result of mental overexertion, harmful habits, such as smoking and drinking, and certain occupational hazards.) Primary hypotonia may arise suddenly and is manifested by collapse, syncope, and shock. Chronic primary hypotonia is characterized by headaches, dizziness, decreased ability to adapt to changes in body position, poor sleep, and palpitations. When the process progresses, hypotonic disease develops. Treatment involves possible removal of the cause of the hypotonia, a strict regimen of work, rest, and diet, gymnastic and physiotherapeutic treatments, drug therapy, and treatment in a sanatorium or health resort.


Molchanov, N. S. Gipotonicheskie sostoianiia. Leningrad, 1962.(Bibliography.)


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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