[Qualification of human body reactions to microgravity].

The purpose of this paper is to qualify developments in the human body during long-term exposure to microgravity in the light of current physiological and pathophysiological postulates. The work is grounded on the analysis of the data about human body reactions to extended stay in microgravity and adopted from the literature. The syndrome of space motion sickness (SMS) evolving at the onset of space flight can be qualified as a temporary reaction to inadequate ambient conditions. In long-term microgravity after mitigation of SMS by dint of appropriate countermeasures, no subjective disturbing symptoms are virtually present. Performance remains on a sufficiently good level, and the body develops stable adaptive reactions and establishes an adequate homeostasis. Back to Earth, the human body undergoes a number of changes which can be qualified as a transient gravity-induced syndrome associated with readaptation of partly deconditioned body to the normal gravity forces.