Does the Temporal Asymmetry of Short-Term Heart Rate Variability Change during Regular Walking? A Pilot Study of Healthy Young Subjects

Abstract

The acceleration and deceleration patterns in heartbeat fluctuations distribute asymmetrically, which is known as heart rate asymmetry (HRA). It is hypothesized that HRA reflects the balancing regulation of the sympathetic and parasympathetic nervous systems. This study was designed to examine whether altered autonomic balance during exercise can lead to HRA changes. Sixteen healthy college students were enrolled, and each student undertook two 5-min ECG measurements: one in a resting seated position and another while walking on a treadmill at a regular speed of 5 km/h. The two measurements were conducted in a randomized order, and a 30-min rest was required between them. RR interval time series were extracted from the 5-min ECG data, and HRA (short-term) was estimated using four established metrics, that is, Porta's index (PI), Guzik's index (GI), slope index (SI), and area index (AI), from both raw RR interval time series and the time series after wavelet detrending that removes the low-frequency component of <~0.03 Hz. Our pilot data showed a reduced PI but unchanged GI, SI, and AI during walking compared to resting seated position based on the raw data. Based on the wavelet-detrended data, reduced PI, SI, and AI were observed while GI still showed no significant changes. The reduced PI during walking based on both raw and detrended data which suggests less short-term HRA may underline the belief that vagal tone is withdrawn during low-intensity exercise. GI may not be sensitive to short-term HRA. The reduced SI and AI based on detrended data suggest that they may capture both short- and long-term HRA features and that the expected change in short-term HRA is amplified after removing the trend that is supposed to link to long-term component. Further studies with more subjects and longer measurements are warranted to validate our observations and to examine these additional hypotheses.

Heart Rate Asymmetry Analysis During Head-Up Tilt Test in Healthy Men

“…This result suggests that PI may not be sensitive to the distinction between long-and short-term HRA. Wang et al (2018) showed significant reduction of PI during low-intensity exercise-5 km/h walking-while changes in GI remained insignificant. Thus, our studies suggest that HUTT impacts upon the increase of heart rate in a different way than physical exercise.…”

“…Due to the occurrence of HRA in the majority of the healthy human population, it has been postulated that the cardiovascular response to external body conditions or illnesses may manifest as a modification in the asymmetry in human heart beat variability. Research has shown that conditions that can affect HRV and its asymmetry are, among others, gastric cancer, mental stress, controlled breathing, or walking (Wang et al, 2013(Wang et al, , 2018Parvaneh et al, 2015;Shi et al, 2019). Naturally, changes in body position affect HRA particularly when it has rapid course.…”

Using Rear Smartphone Cameras as Sensors for Measuring Heart Rate Variability

“…Among these parameters, HRV, which measures small differences in time between successive normal (sinus) cardiac cycles, is recognized as the preferred metric for quantitatively evaluating the function of the autonomic nervous system (ANS) [7]. Numerous articles have reported inverse relationships of HRV parameters to age [8], [9] and exercise [10], [11]. HRV parameters significantly decreases during disease states, such as diabetes [12], hypertension [13], and cancer [14].…”

Bivariate Entropy Analysis of Electrocardiographic RR–QT Time Series

“…A non-stationary trend of ≤ 0.04 Hz was removed from each RR and QT time series using a wavelet decomposition-based algorithm [ 24 ]. Anomalous intervals manifested as spikes in the time series due to either false negatives or false positives during the R-peak detection or caused by erratic compressing/stretching during the QT intervals extraction were sporadically seen.…”