Peripheral skin temperature is a reflection of the blood flow through the vessels under the skin and serves as an indicator of sympathetic activity in the body. When the body is sympathetically activated, blood vessels in the periphery constrict and blood shifts away from the hands and feet into the muscles of the arms, legs and into the head. This shift in blood flow can be measured via the temperature of the hands and feet, indicating the peripheral temperature.
Skin temperature measurement uses a sensitive thermistor which is designed to monitor very small temperature changes. Temperature is measured in degrees Celsius or Fahrenheit. Note that the peripheral temperature is not the same as the core body temperature and the peripheral temperature ranges from 18°C - 36°C or 65°F - 97°F. The higher the temperature value, the more relaxed a person is. It takes some time for the temperature changes to occur. When measuring peripheral temperature, beware the influence of several concurrent factors affecting the temperature measurement, like the blanketing effect or the ceiling effect.