Sudor

Sudor, commonly known as sweat, is a watery secretion produced by sweat glands in the skin. Its primary function is thermoregulation: when sweat evaporates from the skin, it cools the body and helps maintain stable core temperature during heat exposure or physical activity.

Humans have two main types of sweat glands. Eccrine glands are widely distributed and secrete a clear, watery fluid that mainly serves cooling. Apocrine glands are located in areas such as the armpits and groin and release a thicker secretion that can develop odor as bacteria act on it. Eccrine secretion is mainly controlled by the sympathetic nervous system for temperature regulation, while apocrine glands respond to hormonal changes and emotional stimuli.

Secreted sweat is primarily water and electrolytes, especially sodium and chloride, with small amounts of urea, lactate, and other metabolites. The exact composition varies with factors such as exercise intensity, ambient temperature, acclimatization, and individual physiology.

Sweat production is regulated by the brain, notably the hypothalamus, which integrates thermal and other inputs. When body temperature rises, signaling prompts sweating to enhance cooling. Emotional arousal can also trigger sweating in certain areas, particularly the palms, soles, and underarms, via autonomic pathways.

Clinical notes: Hyperhidrosis refers to excessive sweating beyond physiological needs and can affect hands, feet, or armpits. Hypohidrosis or anhidrosis denotes reduced or absent sweating, which can raise heat-related risk. Treatments range from topical antiperspirants and systemic therapies to procedures such as botulinum toxin injections or surgical options in refractory cases. Sweat samples are sometimes used for medical testing or forensic analysis, providing diagnostic or investigative information.