Heart Rate Variability Mainly Relates to Cognitive Executive Functions and Improves Through Exergame Training in Older Adults: A Secondary Analysis of a 6-Month Randomized Controlled Trial.

Patrick Eggenberger,Eling D De Bruin,Simon Annaheim,René M Rossi,Kerstin A Kündig,Thomas Münzer

doi:10.3389/fnagi.2020.00197

Abstract

Heart rate variability (HRV) mirrors autonomic nervous system activities and might serve as a parameter to monitor health status in older adults. However, it is currently unknown which functional health measures, including cognitive, physical, and gait performance parameters, are most strongly related to HRV indices. This knowledge would enable implementing HRV assessments into health monitoring routines and training planning for older adults. Simultaneous cognitive–motor and exergame training may be effective to improve HRV indices but has not been investigated yet. Eighty-nine healthy older adults (≥70 years of age) were randomized into three groups: (1) virtual reality video game dancing, i.e., exergaming (DANCE); (2) treadmill walking with simultaneous verbal memory training (MEMORY); or (3) treadmill walking only (PHYS). Strength and balance exercises complemented each program. Over 6 months, two weekly 1-h training sessions were performed. HRV indices (standard deviation of N–N intervals, SDNN; root mean square of successive R–R interval differences, RMSSD; and absolute power of high-frequency band (0.15–0.4 Hz), HF power) and various measures of cognitive, physical, and gait performance were assessed at baseline and after 3 months and 6 months. Multiple linear regression analyses with planned comparisons were calculated. At baseline, 8–12% of HRV variance was significantly explained by cognitive executive functions and leg strength (inversely related). Verbal long-term memory, aerobic and functional fitness, and gait performance did not contribute to the model (SDNN: R2 = 0.082, p = 0.016; RMSSD: R2 = 0.121, p = 0.013; HF power: R2 = 0.119, p = 0.015). After 6 months, DANCE improved HRV indices, while MEMORY and PHYS did not (time × intervention interactions: first-contrast DANCE/MEMORY vs. PHYS: SDNN p = 0.014 one-tailed, ΔR2 = 0.020 and RMSSD p = 0.052 one-tailed (trend), ΔR2 = 0.007; second-contrast DANCE vs. MEMORY: SDNN p = 0.002 one-tailed, ΔR2 = 0.035, RMSSD p = 0.017 one-tailed, ΔR2 = 0.012, and HF power p = 0.011 one-tailed, ΔR2 = 0.013). We conclude that mainly cognitive executive functions are associated with HRV indices and that exergame training improves global and parasympathetic autonomic nervous system activities in older adults. Periodic assessments of HRV in older citizens could be particularly beneficial to monitor cognitive health and provide indications for preventative exercise measures.

Highlights

Health monitoring that aims to introduce preventative strategies is increasingly important in the rapidly growing population of older citizens
We hypothesized: (1) that variance in heart rate variability (HRV) indices is explained by; (a) cognitive parameters related to executive functions and verbal memory; (b) physical parameters related to physical functioning, aerobic endurance, and leg strength; and (c) gait parameters related to executive functions and, (2) that exercise training-induced adaptations in HRV indices primarily occur in combined cognitive–motor training interventions and in training forms which include aspects of executive functioning
This is the first investigation of a combination of different parameters of cognitive, physical, and gait performance as predictors of HRV indices (SDNN, RMSSD, and HF power) representing global and parasympathetic aspects of the autonomic nervous system

Summary

Introduction

Health monitoring that aims to introduce preventative strategies is increasingly important in the rapidly growing population of older citizens. A promising and measurable parameter to monitor current health status and predict future health outcomes of older adults is heart rate variability (HRV). Low HRV values are usually indicative of compromised health and increased mortality (Ernst, 2017; Kemp et al, 2017). HRV measures may reflect the adaptivity of the brain–body system (Ernst, 2017). HRV indices are associated with numerous domains of cognitive and physical functioning in older adults (Albinet et al, 2010; Ogliari et al, 2015; Freitas et al, 2018)

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