Possible mechanism for modulating cardiovascular system during running in humans

Cardiovascular response to running exercise was studied with a simple pulsatile cardiovascular model. Published experimental data during graded exercise were used to tune the model parameters. Study results show that cardiac output is modulated by rhythmic muscle contractions during running. It oscillates when step rate and heart rate are not synchronised but stabilises when they are synchronised. A maximum cardiac output can be achieved by synchronising step rate with heart rate at an optimal phase delay.