A comparison of male and female runners, weight lifters, and sedentary controls in the R-amp response to exercise testing
Hennings, Denise Laurel
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The purpose of this study was to investigate the R-wave amplitude (R-amp) and hemodynamic response to exercise in 55 volunteers who were divided into age- and sex-matched groups: endurance-trained (RUN), weight- trained (WLT), and healthy sedentary (CTL) controls. Body composition was determined via hydrostatic weighing. Oxygen consumption (V̇O₂), heart rate (HR), blood pressure (SBP/DBP), rate pressure product (RPP), and R-amp in leads II, AVF, V₅, AVR, V₁, and V₃ were recorded during a graded exercise test to exhaustion. Two sums of R-amp were calculated: RS, the R-amp sum of the septal leads AVR, V₁ and V₃; and RL, the sum of R-amp in the left lateral leads II, AVF, and V₅. Data were analyzed using appropriate ANOVA and ANCOVA comparisons. Males exhibited a significantly (p̲ < .001) greater RPPmax than females. The R-amp for males and females was reduced significantly when compared to rest (̲p < .001) in all leads except V₁ at maximal exercise and leads II and V₁ at immediate recovery. There was a significant increase in R-amp from maximal exercise to immediate recovery for males and females in RL and lead V₁. The R-amp in lead V₅ exhibited a significant sex difference (p̲ = .002) at the first minute of exercise, with amplitude increasing for males and decreasing for females. The R-amp in RS and lead AVR exhibited a significant interaction between training and time. The RUN group had a markedly lower R-amp in lead AVR than the CTL group at Min 1 of exercise and both the CTL and WLT groups at maximal exertion. Leads V₃ and RS showed a significant reduction in R-amp for the RUN group, as compared to the WLT and CTL groups at maximal exertion and to the WLT group only at immediate recovery. It was found that the general pattern of Ramp response during exercise was similar between training groups.