| Summary: | Abstract Muscle sympathetic nerve activity (MSNA) is known as an effective measure to evaluate peripheral sympathetic activity; however, it requires invasive measurement with the microneurography method. In contrast, peripheral arterial stiffness affected by MSNA is a measure that allows non-invasive evaluation of mechanical changes of arterial elasticity. This paper aims to clarify the features of peripheral arterial stiffness to determine whether it inherits MSNA features towards non-invasive evaluation of its activity. To this end, we propose a method to estimate peripheral arterial stiffness $$\beta$$ β at a high sampling rate. Power spectral analysis of the estimated $$\beta$$ β was then performed on data acquired from 15 patients ( $$23.7 \pm 9.0$$ 23.7 ± 9.0 years) who underwent endoscopic thoracic sympathectomy. We examined whether $$\beta$$ β exhibited the features of MSNA where its frequency components synchronise with heart and respiration rates and correlates with the low-frequency component of systolic blood pressure. Regression analysis revealed that the local peak frequency in the range of heartbeat frequency highly correlate with the heart rate ( $$R^{2}=0.85$$ R 2 = 0.85 , $$p=6.3\times 10^{-13}$$ p = 6.3 × 10 - 13 ) where the regression slope was approximately 1 and intercept was approximately 0. Frequency analysis then found spectral peaks of $$\beta$$ β approximately 0.2 Hz that correspond to the respiratory cycle. Finally, cross power spectral analysis showed a significant magnitude squared coherence between $$\beta$$ β and systolic blood pressure in the frequency band from 0.04 to 0.2 Hz. These results indicate that $$\beta$$ β inherits the features observed in MSNA that require invasive measurements, and thus $$\beta$$ β can be an effective non-invasive substitution for MSNA measure.
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