Principles and modalities that had been adopted for health evaluation of the first space crews set a basis for the system of medical monitoring of orbital missions longer than a month. Long-term shifts in space called forth the development of as diagnostic so prognostic approaches to health evaluation. One of the methodological fundamentals was the use of the blood circulation system as an indicator of adaptive reactions of the whole body. Data about the cardiovascular reactions to extended exposure to the spaceflight factors on space complex Mir are of major importance for improvement of the effectiveness of medical operations aboard the International space station. Some of the methods applied on Mir can be perfected to meet medical requirements to a mission to Mars.