AJP - Heart and Circulatory Physiology, Vol 243, Issue 6 964-H969, Copyright © 1982 by American Physiological Society
Effect of exercise in healthy men on QRS power spectrum
V. Bhargava and A. L. Goldberger
The effect of exercise on the QRS power spectrum has not been evaluated. We
hypothesized that increased conduction velocity with exercise might
selectively increase high-frequency QRS potentials. Using a digital
electrocardiograph (ECG) cart, a single bipolar chest lead was recorded in
21 healthy adult males at rest and then immediately after treadmill
exercise. Fast Fourier transform analysis of the ECGs was performed using a
128-ms sampling window, including the QRS but not the P wave. Step
discontinuities between PR and ST segments were minimized using a linear
correction function to obviate artifactual increases in high-frequency
content after exercise. The power spectrum plots of rest and exercise data
showed an increase in the amplitude of high frequencies that could not be
accounted for on the basis of noise contamination. For the frequency band
between 187.5 and 250 Hz, the root-mean-square (RSM) voltage of exercise
QRS complexes (10.0 +/- 3.6 micro V) was significantly (P less than 0.02)
greater than that of rest QRS complexes (7.8 +/- 1.2). However, base-line
noise level (computed over a 32-ms interval during the ST segment) was not
different between rest and exercise over this high-frequency band. The same
exercise protocol was also applied in 11 normal male subjects using an
analog ECG cart. For the 187.5- to 250-Hz band, the RMS voltage of the QRS
after exercise (13.0 +/- 1.8 micro V) was also significantly (P less than
0.01) greater than at rest (10.2 +/- 2.8) without any difference in ST
segment noise level over the same frequency range. These data indicate that
exercise causes an increase in the amplitude of high-frequency QRS
potentials in healthy men.
