A cardiovascular control model of 1/f fluctuations in heart rate variability

Recently, the 1/f fluctuations in heart rate variabilities (HRV) of human and animals have been empirically established. They reflect various regulatory mechanisms such as the autonomic nervous system, hormonal systems, and variations in physiological states. So far, researches studying the dynamics of HRV have not directly reached the control rationale of the cardiovascular system, which have been done rather for assessing the above regulatory functions. Here, in order to study control rationale of the cardiovascular system, relationship between the control criteria and the resulting dynamics is investigated by applying an optimal control on a newly developed cardiovascular model. The simulation results suggest that the 1/f fluctuations in HRV is generated under loose control criteria against deviations of blood pressure from its working point in contrast with rigid controls performed in artificial systems