Analysis of transient heart rate response to the active orthostatic maneuver

This study aimed to find the new indices quantitatively characterizing the dynamics of heart rate changes following standing up from the supine position and assess their relationship with age. The intervals between heart beats (R-R) automatically obtained from continuous recording of ECG during the orthostatic maneuver were investigated in 41 healthy men aged 20-59 years, classified into three groups: (22-26 years, n = 14), (33-49 years, n = 13) and (51-59 years, n = 14). The indices describing static differences between steady states and dynamic phase of the response to standing up were analyzed by checking their correlations with age. In transient phase the strongest relationships with age was observed for index describing overshoot in R-R occurring within 30 seconds, above the value of R-R in 8^th minute of standing (r= -0.614). Most of the indices characterizing the amplitude of R-R changes following standing up showed a tendency towards attenuation with age.