The experience gained in the USSR allows the following conclusions: physiological responses to EVA do not depend on flight duration in qualitative and quantitative terms. Physiological responses to EVA are mainly determined by following 3 factors: physiological activities; space suit environmental parameters; physiological stress. This paper reviews problems, associated with altitude decompression sickness; thermal regulation of the body, visual function and physiological psychological stress as well as individual EVA experience in physiological responses.