When attempting to ascertain dancers' fitness levels, essential parameters, such as aerobic and anaerobic capacity, muscular power and strength, flexibility, and body composition, must be considered. Dance is characterized as an intermittent type of exercise, demanding energy from different metabolic pathways (aerobic and anaerobic, lactic or alactic). A dancer's maximum aerobic capacity (ranging from 37 to 57 ml·kg(-1)·min(-1)) is related to his or her dance style, gender, level of technical ability, and status in a dance company. However, dancers' cardiorespiratory requirements during dance classes (essentially designed for the development of technical skills) are significantly lower than during dance performances, indicating that there is a divergence between dance training and performance with regard to demands on dancers' physical fitness. It follows that supplementary fitness training is needed in order to optimize dancers' technical and artistic performance and to reduce the incidence of injury. Traditional aerobic and strength training have been proposed to cover dancers' lack of conditioning; however, it seems likely that high-intensity interval training would more properly meet the requirements of today's choreography. Therefore, with an approach that applies basic exercise physiology to dance characteristics, this review covers the following topics: 1. dance as physical exercise; 2. dancers' aerobic capacity; 3. cardiorespiratory demands of dance classes and performances; 4. supplementary fitness training for dancers; and 5. fitness testing and assessment for dancers.