Category: H

Hallermann-Streiff syndrome is a rare inherited disorder affecting an equal number of males and females. More than 150 cases have been reported in the medical literature, and no known cause has been found other than most likely a new spontaneous genetic mutation. Hallermann- Streiff syndrome is typically diagnosed shortly after birth and usually by the…

Hereditary ataxia is a designation for inherited disorders that involve incoordination of voluntary muscle movements as the result of spinocerebellar degeneration. There are several forms of hereditary ataxia, which are delineated according to how they are manifested genetically. Autosomal recessive forms of hereditary ataxia are expressed by means of a mutated recessive gene. For the…

The blood cells in individuals with hereditary spherocytic hemolytic anemia (HSHA) are sphere-shaped due to a defect within the blood cell as a result of a metabolic defect. Because of the cells’ shape, they are not readily passed through the small blood vessels of the spleen and are often prematurely destroyed by the spleen. The…

Hereditary non-spherocytic hemolytic anemia describes a group of blood disorders that may result from defects in red blood cell membranes, chemical abnormal metabolism, and approximately 16 enzyme deficiencies in the cells, such as glucose-6-phosphate dehydrogenase deficiency. The shape of the red blood cell is not changed as a result of the disorder. The two most…

Hypohydration is below adequate hydration status. The provision of less than the normal amount of water to the body to meet its metabolic demands.  

The term hyperhydration is used to describe the process of consuming additional fluids to promote optimal hydration prior to an event. Recommendations for pre-event fluid consumption are provided in the entry for hydration. Excessive fluid intake, e.g., before athletic events or in some psychiatric illnesses. An endeavor to commence a physical activity session with a…

Hydration status refers to the regulation of water content and distribution within the body. The human body is approximately 60% water, which highlights its critical nature. Water serves a host of life-supporting actions and if too much water is lost (dehydration), the body’s well¬ being becomes compromised. Some principle roles for water in the body…

Hormone sensitive lipase (HSL) is an enzyme that mobilizes fatty acids from triglyceride stored in adipose cells in response to the actions of an array of hormones. Hormones known to activate HSL include epinephrine, norepinephrine, adrenocorticotropic hormone, thyroxine, thyroid-stimulating hormone, glucagon, and growth hormone.  

Heat injury can occur in athletes (as well as nonathletes) during exercise performed at high temperatures and high humidity. While heat injury can easily impair performance, more importantly, when ignored it can progress to the point of serious danger. Early indications of heat injury include dizziness, nausea, tingling sensations, and so forth, which can lead…

A method used to estimate the food intake of subjects by asking them to recall they ate over the last 24 hours.