The haematological and cardiac patterns of adaptation of rabbits to 4,500 m simulated altitude and of readaptation to 400 m

The haemoglobin (Hb), red blood cell count (RBC) and haematocrit (Hct) of 11 male rabbits were measured at weekly intervals during a 5-week exposure period to hypobaric hypoxia (simulated altitude, 4,500 m) and the following 4 weeks after restoring normoxic conditions in a climatic chamber at constant temperature. RBC showed the slowest response, Hct the fastest during adaptation to hypoxia and readaptation to normoxia. The body weight decreased during the 1st week at hypoxia and remained at a reduced level for 2 weeks after the return to normoxia. In female rabbits exposed up to 43 days to hypoxia the heart ventricle quotient (HVQ) (weights of left ventricle + septum/right ventricle) was determined. There was a gradual decrease of HVQ expressing the development of right heart hypertrophy which was not stabilised within the observation period.