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Updated: Aug 21, 2026

Impedance Pneumography for Minimally Invasive Measurement of Heart Rate in Late Stage Invertebrates
Published on: April 4, 2020
Critical scale invariance in a healthy human heart rate
Ken Kiyono1, Zbigniew R Struzik, Naoko Aoyagi
1Educational Physiology Laboratory, Graduate School of Education, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Abstract:
We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of the heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulentlike, cascade heart rate model. These results strongly support the view that a healthy human heart rate is controlled to converge continually to a critical state.
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