Which parameters are recorded in biofeedback?
The most commonly derived bodily signals in biofeedback include:
- Skin conductivity
- Skin Temperature
- Breathing rate and depth of breathing
- Pulse and heart rate variability (HRV)
- Arterial diameter of the temporal artery
- Muscle Tension
The skin conductance
The term skin conductance or skin resistance refers to measurable changes in the electrical properties of the skin.
The sweat glands are controlled by the autonomic nervous system (sympathetic nervous system) and react directly to the smallest emotional, physical and mental changes. The increase in skin conductivity is clearly visible under the influence of a stress stimulus. This stimulus can be e.g. mental activity, emotional excitement or a startle. To put it simply, in a state of stress a person sweats significantly more, the wetter the skin becomes, and as a result its electrical conductivity changes. Biofeedback training can help reduce stress.
For biofeedback via the skin conductance, we offer the eSense Skin Response. This small but high-performance device, in combination with our app, measures the skin conductance using two electrodes on the index and middle fingers. Simple and complex training methods are prefabricated in the app or you can put them together yourself.
The skin temperature
The temperature at the surface of the skin changes depending on how much blood is flowing through the tissue. In a state of increased tension or excitement (stress), these muscles contract and the blood vessels narrow. The skin temperature drops because the tissue is less supplied with blood. In a relaxed state, on the other hand, these muscles relax, which causes the blood vessels to dilate and the skin temperature to rise.
Skin temperature is influenced by, among other things:
- blood flow
- outside temperature
- Body temperature
- Body hair and Hair style
Some of these parameters are controlled by the autonomic nervous system. However, exertion or stress can unconsciously have an influence on these parameters, which is why, conversely, the skin temperature is an indicator of such mental states.
As with all biofeedback applications, the skin temperature is measured, immediately compared with reference values, and a feedback is calculated from this, according to the desired application. A conscious increase in skin temperature is therefore directly associated with a state of being stress-free and relaxed.
We have developed the eSense Temperature for biofeedback via skin temperature. This small but powerful device measures the temperature in combination with our app. You can either hold it yourself or attach the sensor to your finger. Simple and complex training methods are prefabricated in the app or you can put them together yourself.
Pulse and heart rate variability (HRV)
The subject of the heart is a very extensive one, which is why we have also written the HRV-Explanation and HRV Parameters pages. As a central element of the circulatory system, the heart rate depends on the current performance requirements of the body. The heart constantly adjusts its number of beats to the physical and mental stress, this adaptability is visible in the heart rate variability. The heart can also adjust its stroke volume, but this happens very slowly because the heart has to grow physically to do this.
In biofeedback training, heart rate variability (HRV) and pulse are therefore mainly used, these are measured and evaluated via a 1-, 2- or multi-channel ECG – feedback is created from the data obtained in this way. The goal of biofeedback is to increase heart rate variability.
For HRV Biofeedback-Training we have developed the eSense Pulse, this small but high-performance device measures heart parameters via Bluetooth in combination with our app. The module is held by a comfortable strap. Simple and complex training methods are prefabricated in the app or you can put them together yourself.
Respiratory rate and Respiratory depth
There are 2 main measurements of breathing, respiratory rate (breaths per minute) and respiratory amplitude (RA = Respiration Amplitude, how deeply you breathe).
Our state of mind is reflected in our breathing. When we are stressed and tense, we usually breathe quickly, irregularly and shallowly. Both positive and negative stress are reflected in this way. On the other hand, when we are relaxed or asleep, our breathing is usually slow, even, and deep. Auch körperliche Anspannung oder Aktivität kann die Atmung beeinflussen, bspw. Sport.
In everyday life we breathe almost exclusively unconsciously. However, if our breathing patterns are disturbed by chronic stress, pain or other psychological and physical stress, this often leads to discomfort. With breathing training you can train and improve your breathing, achieve deep states of relaxation and significantly increase your general well-being.
For biofeedback training with breathing, we have developed the eSense Respiration, this small but powerful device measures breathing in combination with the Skin Response module and our app. The module is held by a breathing strap that is comfortable to wear. Simple and complex training methods are prefabricated in the app or you can put them together yourself.
The Muscle tension
The activity of the muscles shows up along the fibers of a striated muscle in the form of permanent electrical potential shifts. This electrical activity can be measured on the skin’s surface. This form of measurement is called (surface) electromyography, and the result is an electromyogram.
Striated muscles are controlled by our somatic nervous system and are subject to voluntary control. Every voluntary activation of a muscle leads directly to an increase in the measurement curve of the EMG signal.
In addition, involuntary reactions, such as those due to stress, inner tension and emotional experiences, can also be measured as (tonic) activity in the EMG. EMG biofeedback is therefore also able to report back the general psychophysiological tension. In order to reduce stress and its vegetative symptoms, a reduction in the muscle tone of certain “stress muscles” is sought.
We developed the eSense Muscle for biofeedback training with muscle tension. The eSense Muscle works via Bluetooth and is available in two different versions: for private and professional users.