Coupling of cardiac and locomotor rhythms

of cardiac and locomotor rhythms. J. Appl. Physiol. 66(l): 323-329, 1989.-The pressure within exercising skeletal muscle rises and falls rhythmically during normal human locomotion, the peak pressure reaching levels that intermittently impede blood flow to the exercising muscle. Speculating that a recip-rocal relationship between the timing of peak intramuscular and pulsatile arterial pressures should optimize blood flow through muscle and minimize cardiac load, we tested the hy-pothesis that heart rate becomes entrained with walking and running cadence at some locomotion speeds, by means of elec-trocardiography and an accelerometer to provide signals reflect-ing heart rate and cadence, respectively. In 18 of 25 subjects, 1:l coupling of heart and step rates was present at one or more speeds on a motorized treadmill, generally at moderate to high exercise intensities. To determine how exercise specific thi