5
Skin temperature in general
The temperature at the surface of the skin changes according to blood circulation
through body tissue. The small blood vessels (arterioles) crossing through the tissue
are surrounded by fibers of smooth muscle, which are controlled by the sympathetic
nervous system.
In a state of increased exertion, excitement and stress, these muscle fibers contract,
causing a stenosis of vasculature. This leads to a reduction of skin temperature, since
blood circulation through the tissue is reduced. In contrast, in a state of relaxation, the
musculature is also bound to relax, causing the vasculature to expand. Hence, the skin
temperature rises.
Mental stress often leads to a lower peripheral perfusion and a decrease of skin
temperature at the hands, caused by increased activity of the sympathetic nervous
system. This has a sense of evolution because tension and anxiety originally served
the preparation for an impending flight or an attack. As a result, as much blood as
possible is available in the working muscles (upper arms, thighs and torso), which is
achieved by the narrowing of vessels in the hands, feet and forearms.
For example, think of a speech that you gave in front of an audience or a job interview
panel. If you were anxious in those situations, can you remember having cold (and
sweaty) hands?
This physiological stress reaction can be useless or even harmful in many contexts in
modern society (e. g. mental exertion, worries, psychosocial stress, and anxiety
disorder). A conscious control of physiological stress can help you react in a more
relaxed and efficient manner to many situations. Biofeedback is an established way to
learn this kind of control!
