Chronotropic Response and Heart Rate Variability before and after a 160 m Walking Test in Young, Middle-Aged, Frail, and Non-Frail Older Adults

Abstract

The frailty syndrome is characterized by a decreased capacity to adequately respond to stressors. One of the most impaired physiological systems is the autonomous nervous system, which can be assessed through heart rate (HR) variability (HRV) analysis. In this article, we studied the chronotropic response (HR and HRV) to a walking test. We also analyzed HRV indices in rest as potential biomarkers of frailty. For this, a 160 m-walking test and two standing rest tests (before and after the walking) were performed by young (19–29 years old, n = 21, 57% women), middle-aged (30–59 years old, n = 16, 62% women), and frail older adults (>60 years old, n = 28, 40% women) and non-frail older adults (>60 years old, n = 15, 71% women), classified with the FRAIL scale and the Clinical Frailty Scale (CFS). Frequency domain parameters better allowed to distinguish between frail and non-frail older adults (low-frequency power LF, high-frequency power HF (nu), LF/HF ratio, and ECG-derived respiration rate EDR). Frail older adults showed an increased HF (nu) and EDR and a reduced LF (nu) and LF/HF compared to non-frail older adults. The increase in HF (nu) could be due to a higher breathing effort. Our results showed that a walk of 160 m is a sufficient cardiovascular stressor to exhibit an attenuated autonomic response in frail older adults. Several HRV indices showed to be potential biomarkers of frailty, being LF (nu) and the time required to reach the maximum HR the best candidates.

Frailty Syndrome as a Transition from Compensation to Decompensation: Application to the Biomechanical Regulation of Gait

“…Additionally, we recorded video footage of the gait experiment of each participant to assist in interpreting the accelerometer data. We have partially published the results of the analysis of the physiological variables [38,45]; the present contribution focuses on the analysis of gait regulation using data from 3-axial accelerometry.…”

“…This study was conducted from September 2016 to April 2017 at the Hospital General de México "Dr. Eduardo Liceaga" (HGM). A total of 89 Mexicans participated voluntarily and were divided into four groups, as shown in Table 1: (i) young control adults aged 19-29 years (group C1, n = 27), (ii) middle-aged adults aged 30-59 years (group C2, n = 16), (iii) non-frail older adults over 60 years old (group nF, n = 15), and (iv) frail older adults over 60 years old (group F, n = 31) [38]. In Mexico, people over 60 years old are considered older adults [39].…”

“…The middle-aged adults who participated in the study were family members and/or caretakers of frail and non-frail older adult participants; they were completely independent and functional, and therefore nonfrail. The inclusion and exclusion criteria have been explained in a previous publication [38] and are summarized here. To obtain a more realistic sample of frailty within the older adult population, we included individuals of both genders and with diverse medical histories.…”

“…The participants walked the trajectory in one direction and then turned around to complete the trajectory in the other direction, covering a total distance of L = 160 m, see Figure 1 and the description in Ref. [38]. This distance was a choice of convenience, corresponding to the dimensions of the square, but also approximately corresponds to a 3 min walking test, which is a validated test [46].…”

Validity and Reliability of Short-Term Heart Rate Variability Parameters in Older People in Response to Physical Exercise

“…In a recent study, a group of frail and non-frail older people was compared, assessing the HRV response to a 160-m walking test, showing that frail older people exhibit an impaired response compared to non-frail individuals [23]. Although similar evidence exists in this regard [24][25][26], it is already known that the differences in the autonomic modulation of individuals can be influenced by the type, duration, and intensity at which the exercise is performed [27].…”