Heart rate variability metrics demonstrated poor to good day-to-day reliability (ICCs 0.33-0.93) in healthy highly active adults, while linear and nonlinear HRV metrics significantly declined with age.
Observational (n=66)
No
Heart rate variability metrics are reproducible between days in healthy highly active younger and older adults, and there is a significant decline in linear and nonlinear HRV metrics with age.
Abstract Purpose To investigate the inter-day reliability of time-domain, frequency-domain, and nonlinear HRV metrics in healthy highly active younger and older adults. The study also assessed the effect of age on the HRV metrics. Methods Forty-four older adults (34 M, 10F; 59 ± 5 years; V̇O{₂₄₀₊} V ˙ O 2peak = 40. 9 ± 7. 6 ml kg −1 min −1) and twenty-two younger adults (16 M, 6F; 22 ± 4 years; V̇O{₂₄₀₊} V ˙ O 2peak = 47. 2 ± 12. 8 ml kg −1 min −1) attended the laboratory. Visit one assessed aerobic fitness through an exercise test. In visits two and three, participants completed a 30-min supine RR interval measurement to derive the HRV metrics. Results The younger group (YG) and older group (OG) demonstrated poor to good day-to-day relative and absolute reliability for all HRV metrics (OG, ICCs = 0. 33 to 0. 69 and between day CVs = 3. 8 to 29. 2%; YG, ICCs = 0. 37 to 0. 93 and between day CVs = 3. 5 to 36. 5%). There was a significant reduction in ApEn (P < 0. 001), SampEn (P = 0. 031), RMSSD (P < 0. 001), SDNN (P < 0. 001), LF power (P < 0. 001) and HF power (P < 0. 001), HRV metrics with ageing. There was no significant effect of age the complexity metrics DFA α1 (P = 0. 107), α2 (P = 0. 147) and CI-8 (P = 0. 493). Conclusion HRV metrics are reproducible between days in both healthy highly active younger and older adults. There is a decline in linear and nonlinear HRV metrics with age, albeit there being no age-related change in the nonlinear metrics, DFA α1, α2 and CI-8.
Fennell et al. (Wed,) conducted a observational in Healthy highly active adults (n=66). Inter-day reliability assessment was evaluated on Inter-day reliability of HRV metrics (Intraclass correlation coefficients). Heart rate variability metrics demonstrated poor to good day-to-day reliability (ICCs 0.33-0.93) in healthy highly active adults, while linear and nonlinear HRV metrics significantly declined with age.