Hypobaric Decompression Sickness and Adynamia

INTRODUCTION A large discrepancy exists between ground-based estimates of decompression sickness (DCS) incidence during simulated extra-vehicular activity (EVA) and actual reports of DCS from EVA crewmembers. The discrepancy could be due to the effect of gravity during ground-based DCS studies. The lack of weight-bearing loads (sometimes named adynamia) will relieve pressure within the joints, particularly in the lower limb joints, in space. This may reduce gas bubble formation and subsequent symptoms of DCS on orbit in comparison to the conditions during ambulatory studies conducted under 1 G. Preliminary reports have indicated that adynamia may reduce DCS incidence. However, no peer-reviewed publications have definitely answered the question.