Effects of simulated prolonged restrained sitting on physical and physiological states

Abstract

Introduction: Advancement in aerospace technology, and resultant change in operational capabilities has posed unique challenges on the aircrew, who is required to operate for prolonged periods seated and restrained. Examination of the effects of prolonged restrained sitting on physical and physiological states was the desired objective of the study. Material and Methods: Longitudinal evaluation of subjective appreciation of physical discomfort and pain, and physiological parameters, namely, heart rate (HR), blood pressure (BP), oxygen saturation (SpO2), skin temperature, and calf girth changes across 6-h of simulated prolonged restrained sitting was undertaken among 15 healthy male non aircrew volunteers with mean age of 31.2 ± 3.63 years. Subjective discomfort was assessed by Category Partitioning Scale (CPS) and pain by Short-Form McGill Pain Questionnaire (SF-MPQ). Results: Prolonged restraint sitting of 6-h resulted in a significant increase in calf girth. Significant changes were also observed in CPS and SF-MPQ scores indicating an increase perception of discomfort and pain. Changes in HR, MAP, SpO2, and lower limb skin temperature were also observed even though these changes were lower in magnitude. Conclusion: The pain and discomfort following 6-h of prolonged restraint sitting were found to be appreciable by the subjects. This, along with a significant change in the calf circumference and other physiological parameters were possibly due to effects of venous pooling as a result of sitting for prolonged periods. The effects so observed could have potential flight safety implications and affect mission effectiveness. However, these findings need to be examined in actual cockpit conditions where the seat is more ergonomically designed; yet the aircrew is subjected to a wide spectrum of additional aeromedical stressors.