Skin response in general

Skin response, also known as galvanic skin response (GSR), electrodermal response (EDR), or skin conductance (SC) is a measurement method based on the bio-electrical properties of the skin. The skin conductance depends on the activity of the sweat glands of the skin and reacts to the smallest changes, which we can’t detect as wet hands yet. The eSense Skin Response applies a very small, safe and unnoticeable electrical voltage, which results in an electrical current to the skin. Through the changes of this small current, we can measure the activity of the perspiration glands of the skin far below the threshold of self-perception. The higher the activity of the sweat glands, the more the skin gets wet and the better the current is conducted. As a result, the Skin Conductance rises.

The Skin Response measures the Skin Conductance in Micro Siemens or µSiemens. Skin conductance is measured in µSiemens or symbolized as µS (where µ denotes a millionth and Siemens is the unit of conductance). “Skin resistance” is also a common term, simply denoting the inverse of conductance (1S = 1/Ω).

The activity of the perspiration glands is determined by the autonomic nervous system, which contains two major subunits: the parasympathetic nervous system and the sympathetic nervous system. The perspiration glands of the skin are solely controlled by the sympathetic nervous system, making them a good indicator for inner strain and stress. The sympathetic nervous system reacts to stress stimuli by activating all the “emergency functions” of the body, bringing it to a state of heightened responsiveness: Pulse and blood pressure rise along with the glucose level in the blood and general alertness. With these changes comes the effect of “wet hands” on which our measurement relies.

We all know a time in our lives when we got wet hands. Think of the speech you gave in front of an audience, or a job interview. If in those situations you were excited, can you remember the cold, sweaty hands?

A scientific theory for this effect assumes that our ancestors needed wet hands to have a firmer grip on things; for example, in an escape or pursuit through difficult terrain. When the threatening situation is over, the parasympathetic nervous system becomes dominant: Pulse, blood pressure and glucose level fall again. The body enters a rest state to allow recuperation. The hands become dry again.

The increased activity of the perspiration glands through a (stress) stimulus is easily visible through the associated increase in skin conductance. The stimulus can be mental or emotional strain, or taking a sudden, deep breath, or a startling action like someone unexpectedly clapping hands or the loud drop of an item onto the floor. Just try it with the eSense – you will easily see the effects!

We combine the measurement and feedback of the skin conductance in the eSense app with guided relaxation exercises and guided meditations and offer you an overall experience that goes beyond biofeedback. In addition to extensive feedback variants, you have the option of evaluating your measurements with many statistics, documenting your progress and exporting the recordings as CSV and PDF files. Your data belongs only to you! You have full access to the raw data.