METHOD: Baseline HRV, age, and sex data were collected from 470 subjects without cardiovascular conditions. Short-term HRV was recorded using Biocom Active ECG units (Biocom, Seattle, Wash). Subjects were divided by age into 10-year intervals and by sex for HRV analysis.
RESULTS: Total power, representing the overall autonomic activity, decreased consistently from the age groups 10+ to 80+ years (P < .001). Both the low frequency (sympathetic activity) and high frequency (parasympathetic activity) declined (P < .05) as age increased. Sex had a significant effect on heart rate, R-R interval, high frequency, normalized low frequency, normalized high frequency, and low frequency-high frequency ratio. Sex did not seem to affect the SD of the normal-to-normal heartbeats and total power (P > .05) despite the significant heart rate changes (P < .05).
CONCLUSION: This study demonstrated that age had a greater impact on HRV than sex. The older age group had consistently lower HRV than younger people. The values generated in this study may be useful in health care settings to determine abnormal ranges of HRV under different clinical and experimental conditions.
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