Physiological responses and adaptations of women to exercise are influenced by her genetically determined morphological and functional characteristics, and by her level of physical fitness. Physiological responses of women during submaximal and maximal exercise differ quantitatively from those of men but adaptations to training are qualitatively similar in both. Studies demonstrate that differences between the sexes in performance of athletic events that require high aerobic or anaerobic capacity are due, to a large extent, to differences in body structure and composition: the average woman is smaller and lighter and has less muscle mass than the average man. These characteristics influence physiologic responses of the musculoskeletal, cardiovascular and respiratory systems during exercise. This article describes physiological responses of women during exercise in relation to her sex related morphological characteristics, and the adaptations that occur with physical training.