An optimal control model of 1/f fluctuations in heart rate variability

We investigate the generation mechanisms underlying the 1/f fluctuations in HRV in the context of an optimal control of the cardiovascular system. First, the phenomenon is experimentally quantified for human and cat HRV. Second, the relationship between the resulting dynamics of HRV and the regulatory criteria of optimal control is investigated by using a newly proposed cardiovascular system model. Finally, an operational point of the model is hierarchically controlled to simulate changes in physiological states, including the state of consciousness. This hierarchical control mechanism is suggested to be essential for generating the 1/f HRV fluctuations, and their physiological significance is discussed. Through these analyses, a possible control strategy of the cardiovascular system is suggested.