The feet have more than 250 000 sweat glands. Although the sweat usually does not smell, the bacteria, which in warm weather start reproducing faster, cause the unpleasant smell.
In most cases, sweating is due to physical activity, mental stress, or hot weather, and it is absent during the night. Some people though, experience perspiration as a result of minor activities or even without particular reason. Regardless to what it is due, the abundant sweating generates many inconveniences and can lead to a variety of problems in everyday life including, and perhaps most serious, social exclusion.
A typical feature of perspiration is that it could be inherited, because every third person, suffering from excessive sweating (hyperhidrosis), has a relative with the same problem. It starts occurring during the adolescence stage of life.