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Sweating & Hyperhidrosis

 

To understand hyperhidrosis, it is first necessary to understand why the body sweats at all, and the mechanism by which this takes place.

Body processes and muscle activity results in the generation of significant amounts of heat. To maintain a steady internal temperature, necessary for cell function, some of this heat needs to be removed from the body.  Sweating, or ‘Perspiration’, is one of the means by which the human body controls this internal temperature.

The evaporation of sweat from the skin surface has a cooling effect due to the latent heat of evaporation of water. Hence, in hot weather, or when the individual's muscles heat up due to exertion, more sweat is produced. Sweating is increased by nervousness and nausea and decreased by cold

Sweat glands, or sudoriferous glands, are exocrine glands found under the skin. There are two types: Apocrine glands and merocrine sweat glands

Apocrine sweat glands are coiled tubular glands located at the junction of the dermis and subcutaneous fat, from which a straight portion inserts and secretes into the infundibular portion of the hair follicle. They produce a viscous, cloudy, and potentially odorous secretion  Note that the odour from sweat is due to bacterial activity on the secretions rather than the secretions themselves. East Asians have fewer apocrine sweat glands compared to people of European or African descent, and it may be for this reason that they are less susceptible to body odor. Those of an African decent tend to have more, and larger apocrine glands. Apocrine sweat glands are found only in certain locations of the body: the axillae (armpits), the areola of the nipples, and the anal region. The stimulus for the secretion of apocrine sweat glands is adrenaline, which is a neurotransmitter carried in the blood

Eccrine glands (or merocrine glands) are the major sweat glands of the human body, found in virtually all skin.. They produce produce a clear, odourloess substance, consisting primarily of water and Sodium Chlride NaCl (salt), although the NaCl is predominantly reabsorbed in the duct to reduce salt loss. It is the Eccrine glands that  are active in thermoregulation, controlled by the hypothalamus.

Eccrine glands are composed of (1) an intreaepidermal spiral duct, the "acrosyringium," a straight dermal portion, and  a coiled acinar (grape like) portion in the dermis or hypodermis. They are mainly controlled via the sympathetic nervous system.

Sweating is controlled from with in the preoptic and anterior regions of the hypothalamus, under the influence of thermosensitive neurons with in this region and, to a lesser extent, temperature receptors in the skin.

There are two situations in which our nerves will stimulate sweat glands, making us sweat: during physical heat and emotional stress. In general, emotionally induced sweating is restricted to palms, soles, and sometimes the forehead, while physical heat-induced sweating occurs throughout the body. [

Sweat is predominantly made up of water, but also contains an array of minerals, as and urea. Mineral composition will vary between individuals and during the day for the same individual, depending on their activity tevel, ambient temperature, stress level to name but a few.

 

 

Hyperhidrosis is a clinical condition that causes excessive sweating, beyond the needs of body temperature control.

 

Continue here to read about the Types of Hyperhidrosis