Implementation of a 10-meter radius centrifuge model into a simulator of the human cardiovascular system: Effect on heart rate, stroke volume, and aortic pressure

Abstract

Greater interest in long term space travel is creating demand to develop artificial gravity systems that minimize the negative effects of long-term microgravity exposure. However, due to practical constraints of understanding the physiological effects of artificial gravity systems, we propose a cardiovascular simulation to better understand the physiological impacts of an artificial gravity gradient created through the centrifugal force of a rotating spacecraft. The purpose of these simulations is to understand the effects of artificial gravity systems during space travel. We hypothesized that an artificial gravity system will not have significant effects on the cardiovascular system if it induces the same gravity gradient in an upright human as exists on Earth. For this reason, a 10-meter radius, 1 radian/second centrifuge system was chosen to mimic the effect of the gravity gradient on Earth. We used a modified version of the CVSIM program developed to model cardiovascular responses to orthostatic challenges ( https://physionet.org/content/cvsim/1.0.0/ ). CVSIM is a 21-compartment, lumped parameter model with control systems for the cardiopulmonary and arterial baroreflexes. The existing tilt test simulation within the CVSIM program was modified to create a simulation of the centrifuge. A 500-second-long simulation resulted in an average heart rate of 79 beats/minute, an average stroke index of 46 mL/beat/m 2 , and average pressures in the ascending aorta of 99 mmHg during systole, and 72 mmHg during diastole. These values were achieved by 150 seconds into the 500-second simulation. In comparison, prior to the onset of the centrifugation, initial heart rate, stroke index, and ascending aortic pressure compliance were set at 70 beats/min, 46 mL/beat/m 2 , and 0.28 ml/mmHg, respectively, based on published norms in humans. These preliminary data suggests that this artificial gravity system may produce viable physiological conditions for the cardiovascular system. Further research, especially with longer simulations, is necessary to determine if a rotating spacecraft could ease the negative impacts of microgravity over an extended time. This work is supported by Iowa Space Grant Consortium/NASA BASE grant No.103428-19-20 (AP, MJL) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.