Heart Rate Variability in Different Age Groups

Objective: To study the heart rate variability (HRV) of 40 healthy volunteers of different ages, divided into four equal groups, with the following characteristics: a) group 1, 20 to 30 years old (mean plus or minus standard deviation = 23.0 plus or minus 2.8 years); b) group 2, 31 to 40 years old (34.7 plus or minus 2.1 years); c) group 3, 41 to 50 years old (46.4 plus or minus 3.4 years); and group 4, 51 to 60 years old (54.9 plus or minus 2.0 years). Method: The investigation tool was HRV in the time (TD) and frequency (FD) domains, in two situations: 1) under controlled resting conditions (CRC); 2) during active postural maneuvers (APM). Results: Under CRC, the HRV in TD and FD was lower in the 51-60 age group than in the 20-30, 31-40 and 41-50 groups. During APM, comparison between the supine and biped positions within the groups showed that there was a progressive reduction in the magnitude of sympathetic and parasympathetic responses as subject ages increased. Analysis of 0-10s heart rate delta (A 0-10s) for changing from the supine to the biped position also showed progressive reduction with aging: means of +42 bpm, +35 bpm, +30 bpm and +25 bpm, respectively for the 20-30, 31-40, 41-50 and 51-60 age groups. Conclusion: HRV analysis, both under CRC and during APM, is an important tool for investigating cardiac autonomic function in relation to human aging.