It is normal for people to perspire, or sweat, when they are warm or experiencing emotional stress. Sweating helps maintain proper body temperature by keeping the body cool. When people are under stress, sweat glands contract, which pushes sweat to the skin surface. People may lose several quarts of fluid in perspiration.
There are two types of sweat glands on the skin: the eccrine glands and the apocrine glands. About 2-5 million eccrine glands are found on almost all areas of skin. When the body's temperature increases, the nervous system signals the eccrine glands to secrete sweat onto the skin. The sweat is primarily made up of salt and water. When the sweat evaporates, it cools the body.
Apocrine glands are present in areas that contain many hair follicles, including the armpits, groin, and scalp. Apocrine glands secrete a fatty sweat that contains pheromones. Unlike eccrine glands, which respond to heat, apocrine glands respond to emotional stress and sexual activity. When the sweat touches the skin, bacteria on the skin start to break it down. When the bacteria break down apocrine sweat, it can cause an offensive odor.
When someone sweats more than the average, the condition is called hyperhidrosis. Sweating too much may be embarrassing if it is visible through the clothing or if it causes an offensive odor. Excessive sweating may also be a sign of a more serious condition, such as an infection (like the flu), low blood sugar levels, or certain types of cancer. In addition, some medications, menopause, and low testosterone levels may also lead to increased sweating.
When people sweat too little or not all, the condition is called anhidrosis. Certain types of cancer, severe burns, and extreme dehydration are just some of the possible causes of anhidrosis. This condition ranges from mild to life threatening. If anhidrosis is localized to one part of the body, the condition is generally not a major health concern. However, if many of the sweat glands are involved it can be dangerous because sweating is an important function that prevents the body from overheating. If the body is unable to sweat enough, the person's body temperature may become too hot, and it can potentially lead to organ damage or failure.
Treatment to reduce or increase sweating varies depending on the severity of the underlying cause.
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