Why does sweating occur in human beings?

Hint: Sweating also known as perspiration or diaphoresis is the result of thermoregulation by the hypothalamus. They are released by sweat glands which are present in the body. They provide the cooling effect required for the body. But excessive sweating is a sign of certain diseases.

Complete answer:
Sweating is an involuntary action which is controlled by the autonomic nervous system. This is a part of thermoregulation which means regulation of body temperature. Face, armpits, palms of hands and soles of feet are common sweating areas. Sweating occurs in human beings for temperature regulation. Sweating is the reason for cooling down the body temperature through the process of evaporation.

During summer, sweating increases more than the limit. This sends feedback to the brain which will signal the hypothalamus to make the body cool, thereby sweating happens. Sweat will leave the body via pores on the skin and evaporates into the atmosphere. Since excess sweating could cause dehydration, it is better to take plenty of water to maintain the fluid balance in the body.

Heat and humidity are not the only cause of sweating, other causes can be excess work, exercises, hormonal and emotional fluctuations, spicy foods that can cause gustatory sweating, and some medications and illness.

Note: Excessive sweating is termed as hyperhidrosis. It is a condition where excessive sweating from hands, armpits, feet, and groins would begin while the absence of sweating is called anhidrosis. Hyperhidrosis is a disorder and a symptom of various diseases like endocrine diseases, neurologic and other systemic diseases.