Effect of a Series of Short-Arm Centrifuge Rotations on Antiorthostatic Responses of Arterial Hemodynamics in Healthy Subjects (Laser Doppler Flowmetry Data)

The development of a methodology for the use of a short-arm centrifuge (SAC) as a novel countermeasure and/or a means of correcting orthostatic disorders requires investigation of the effects of different SAC rotation protocols on antiorthostatic hemodynamic responses. The ultimate goal of these studies is to develop safe and effective protocols for the application of artificial gravity (AG) generated by the SAC, primarily for use aboard orbital space stations, as well as for practical healthcare applications. In the present study, hemodynamic responses to longitudinal g-loads (+Gz) during a series of five SAC rotations were investigated using laser Doppler flowmetry (LDF) with a modified (shortened) protocol compared to previous studies. Reducing the duration of rotation to 45 min (instead of 60 min in the 2022 experiment) was shown to improve overall tolerability without reducing effectiveness. It was found that a series of five rotations using the shortened protocol, with alternating g-levels of +1.27 and +2.06 Gz, exerted a stimulating effect on antiorthostatic responses of peripheral arterial hemodynamics. This was confirmed both by comparison of data obtained during the first and fifth SAC rotations and by the results of passive postural tests used as controls. These findings suggest that the development of different rotation protocols may be required in the future to address specific tasks.