The Institute of Medicine (2012), in its report titled Physical Fitness and Health Outcomes in Youth, recommended the term cardiorespiratory endurance for use in assessing health-related fitness with youth. Consistent with that report, Corbin and colleagues (2014, p. 28) noted the following:
Cardiorespiratory endurance is the recommended term for the fitness component frequently described as cardiovascular fitness, aerobic fitness, cardiorespiratory fitness, or cardiovascular endurance. Numerous terms are used to describe the component of fitness associated with functioning of the cardiovascular, respiratory, and muscular systems. However, there are subtle differences in meaning and interpretation among these different terms. For field measures, the IOM (2012) recommends the definition by Saltin (1973); cardiorespiratory endurance is “the ability to perform large-muscle, whole body exercise at a moderate to high intensity for extended periods of time” (IOM, 2012, p. 1-2). The term cardiorespiratory endurance, and its definition, is appropriate for use in fitness education because it reflects the ability of a person to perform functional fitness activities of daily life associated with the three principal systems supporting performance (cardiovascular, respiratory, muscular).
Corbin and colleagues (2014, pp. 28-29) further indicated the following:
Performance on the commonly used PACER test, for example, reflects cardiorespiratory endurance since it directly relates to the ability to sustain aerobic activity over an extended period. Lap scores on the PACER provide baseline information for both health information (where you stand in terms of health) and functional information (how much you can do and if you are getting better) and are useful in personal program planning. Lap scores can also be converted to estimates of aerobic capacity, but the raw lap scores provide unique meaning about functional fitness. The mile run test also can reflect cardiorespiratory endurance, but it is not as widely used (or endorsed) due to the issues with motivation and pacing. The walk test, a test option offered in FG, provides an alternative assessment of cardiorespiratory endurance that has particular utility for youth with low fitness, special needs, and those who are just beginning physical activity.
While cardiorespiratory endurance and aerobic capacity are commonly considered to be synonyms, for educational purposes it is appropriate to differentiate between the two. Cardiorespiratory endurance is measured by field tests and reflects both health and functional fitness. Aerobic capacity, in contrast, reflects the overall capacity of the cardiovascular and respiratory systems, but not necessarily functional fitness.
Aerobic capacity reflects the maximal amount of oxygen that can be taken in and used by the body. It is typically expressed as maximal oxygen uptake (VO2max) and VO2max is generally considered to be the best measure of aerobic capacity. Because differences in body size can influence oxygen uptake (i.e., bigger people have more body tissue and use more oxygen), the measure of aerobic capacity is most commonly expressed relative to body weight or milliliters O2 consumed per kilogram of body weight per minute (ml/kg/min or mL/kg-1/min-1).
In summary, cardiorespiratory endurance is the preferred term for use in health-related fitness field testing of youth when referring to the ability to sustain aerobic exercise for a long period. Aerobic capacity refers to the amount of oxygen that can be used in maximal exercise. Tests of aerobic capacity are typically done in a laboratory setting. Aerobic capacity scores are used to validate tests of cardiorespiratory endurance; these scores can be estimated from scores on field tests.
Corbin, C.B., Welk, G.J., Richardson, C., Vowell, C., Lambdin, D., & Wikgren, S. (2014). Youth physical fitness: Ten key concepts. JOPERD, 85, 2, 24-31.
Institute of Medicine. (2012). Fitness measures and health Outcomes in youth. Washington, DC: National Academies Press.