Left ventricular response to dynamic and static exercise: evaluation by radiocardiography in healthy men

The effects of dynamic and static exercise on left ventricular haemodynamics were compared in 13 healthy male volunteers using single detector radiocardiography. Static hand grip effort was performed for four minutes at 30% of the maximum contraction. During dynamic exercise the subjects bicycled on an ergometer to 85% of the predicted heart rate for their age. Static exercise increased the heart rate, systolic and diastolic blood pressure and cardiac output (p less than 0.001 for all), but there were no significant changes in the stroke volume, left ventricular end-diastolic volume or ejection fraction from the resting values. Dynamic exercise in a supine position clearly increased the heart rate, systolic blood pressure and cardiac output (p less than 0.001 for all) to a greater extent than the hand grip, together with a significant augmentation of the stroke volume (p less than 0.001) and the ejection fraction (p less than 0.01). The dynamic exercise produced only an insignificant increase in left ventricular end-diastolic volume. Thus, the normal left ventricular volume response to the increase in preload during dynamic exercise was a significant augmentation of stroke volume and ejection fraction. On the other hand, the static exercise in the same subjects mainly increased the left ventricular afterload while the left ventricular volume changes remained minimal.