Detection of sympathetic nervous system weakness

ANS Analysis

With conspicuously high parasympathetic values and condition disorders of the patient exhibiting signs of exhaustion and lack of energy, the question arises whether this is caused by a regulatory disturbance with a hyperactive parasympathetic nervous system and a weakened sympathetic nervous system.

In order to be able to assess these patients better, an orthostatic test or change of position should be carried out. 130 RR intervals are measured for the patient while lying down. This is followed by an acoustic signal as well as the note: ‘Please stand up now’. Thereafter, 210 RR intervals are measured while standing.

In contrast to the pulsed breathing with which one can control the switching on of the parasympathetic nervous system, the change of position causes a stress impulse, with which one can control the shutdown of the parasympathetic nervous system. In comparison, a clear difference between lying down and the standing position should be recognizable. The heart rate (HR) and the stress index (SI, red bar) should increase, whereas the parasympathetic nervous system (RMSSD, blue bar) should decrease.

None, or only a very slight change in the parameters is an indication of a regulatory disorder with a dominant parasympathetic nervous system and a weakened sympathetic nervous system.

The following graphs show an ideal result of the orthostatic test. The standing phase clearly differs from the lying phase.

1. HRV-recording with course of parasympathetic activityHeartratevariabilty_Orthostasis_realtime

2. HRV-recording with rhythmogram, histogram and scatter plotHeartratevariabilty_Orthostasis

3. Comparison of parameters: pulse, sympathetic and parasympathetic index during lying and standing positionHeartratevariabilty_Orthostasis


During the measurement, someone should always stay with the patient.

The patient is first measured while lying down. After a preset time, ANS Analysis gives the signal "Please stand up". The remaining measurement is then carried out in the standing position. The total measurement time is 340 RR intervals, approx. 5 minutes.

In the end, the measurement in the lying position is compared with the one in the standing position.