Short‐term heart rate variability: A potential approach to frailty assessment in older adults.

Objectives: This study aimed to evaluate cardiac autonomic modulation using short‐term heart rate variability (HRV) and compare it among frailty statuses in older Indian adults. Methods: A total of 210 subjects aged 60 years and above were recruited into three groups: frail (n = 70), pre‐frail (n = 70), and non‐frail (n = 70) from the outpatient department of Geriatric Medicine at a tertiary care hospital in India. Frailty status was assessed using the Rockwood frailty index (FI) criteria. HRV was derived from a 5‐min ECG recording of standard limb leads and assessed using time domain, frequency domain, and nonlinear analysis of cardiac interval variability. Results: The HRV parameters indicative of parasympathetic modulation such as SDNN, SDSD, rMSSD, NN50, pNN50, absolute HF power, and SD1 were significantly lower in frail subjects compared with both pre‐frail and non‐frail subjects (P < 0.05). Absolute LF power and SD2 were also lower in frail subjects compared with pre‐frail and non‐frail subjects (P < 0.05). Measures of sympatho‐vagal balance (LF/HF and SD1/SD2 ratios) did not show statistical significance. The FI demonstrated negative correlations with all HRV parameters. Conclusions: Frail individuals exhibit decreased sympathetic and parasympathetic modulation compared with pre‐frail and non‐frail individuals, although maintaining a balanced sympatho‐vagal state. Furthermore, autonomic modulation declines progressively with increasing frailty. [ABSTRACT FROM AUTHOR]