Abstract
It has been found that sustained centrifugation on Earth may evoke sickness symptoms that are similar to those of theSpace Adaptation Syndrome (SAS). As in SAS, incidence of this ‘Sickness Induced by Centrifugation’ (SIC) is about 50% andthe symptoms are particularly evoked by head movements. By systematically varying the G-load and duration of centrifugation,the current study investigated the characteristics of the gravitational stimulus that is required for SIC to occur. Subjects wereexposed to centrifugation at 2 and 3Gx, for a duration of 45 and 90 minutes. A standardized head movement protocol was usedto evoke SIC after centrifugation. The results show that in six out of 12 subjects (50%) no serious symptoms were elicited. Inthe remaining subjects, the effects of the 3G runs exceeded those of the 2G runs, and within each G-level symptom intensity washigher for the 90 min than for the 45 min exposure. An exponential fit on this data showed that the time constant of adaptationto the gravitational stimulus was about 60 minutes. This suggests that short duration exposures (i.e.<60 min) are not likely toinduce serious SIC.
