Correlation between degree of autonomic nervous system impairment and quality of life indices in older adults

INTRODUCTION: The increase in the world’s elderly population in recent decades calls for research on quality of life during the aging process. Heart rate variability (HRV) evaluates the modulation of the autonomic nervous system (ANS) and indicates the heart’s ability to respond to multiple physiological and environmental stimuli, as well as to disease. OBJECTIVE: To investigate the perceived quality of life of older people and its association with HRV. METHOD: Twenty-nine subjects (69 ± 7.76 years) were selected at a preventive medicine center and completed a questionnaire (World Health Organization quality of life assessment — old module: WHOQOL-OLD). The HRV data were collected for 20 minutes in the supine position using a Polar RS800CX frequency meter. RESULTS: Using the median value as a cut-off point, the sample was divided into two groups: WHOQOL-OLD ≥ 92 (n = 15: better quality of life) and WHOQOL-OLD ≤ 91 (n = 13; lower quality of life). For the HRV time-domain variables RMSSD and pNN50, there were higher values in the WHOQOL-OLD ≥ 92 group (p = 0.0413 and p = 0.0222, respectively). For the frequency-domain variables, low-frequency (LF), high-frequency (HF) and Total Power, there were also higher values in the WHOQOL-OLD group ≥ 92 (p = 0.0195, p = 0.0170 and p = 0.0287, respectively). The non-linear variable SD1 was significantly higher in the WHOQOL-OLD ≥ 92 group (p = 0.0413), while DET% was significantly higher in the WHOQOL-OLD ≤ 91 group (p = 0.0253). CONCLUSIONS: Better quality of life in older adults is associated with normal ANS function, represented by higher values found through three HRV analysis methods. This indicates the importance of a healthy lifestyle for healthy aging, which includes improvement in autonomic function and, consequently, quality of life.