2000 Volume 45 Issue 6 Pages 679-694
Cardiorespiratory fitness or cardiorespiratory endurance fitness(CREF) refers to the ability of the body to sustain prolonged, rhythmical exercise. The great interest over the last several decades in the importance of CREF stems from a series which report that endurance exercise performance is highly correlated to maximal oxygen uptake (VO_2max) and oxygen uptake at which systematic changes in lactate(LT:lactate threshold) and/or respiratory gas exchange measurements (VT:ventilatory threshold) occur as a result of an elevated metabolic acidosis. LT and VT have been used interchangeably with anaerobic threshold(AT) by a number of researches. VO_2max is the highest rate of oxygen uptake attainable for a given form of maximal or exhaustive ergometry. VO_2AT was first defined by Wasserman et al.(1973) as the level of oxygen uptake, above which aerobic energy production is supplemented by anaerobic mechanisms. In recent years, accumulative epidemiologic research results suggest that low levels of CREF, as represented by VO_2max or VO_2AT, are associated with increased risk of such chronic diseases as coronary artery disease, stroke, hypertension, diabetes, and several forms of cancer. Thus, from both human performance and health status perspectives, the importance of assessing CREF is very clear. However, direct measurement of CREF requires considerable expense in terms of high-quality equipment and well-trained exercise testing personnel. Close approximation of CREF using standardized exercise testing protocols also requires specialized equipment and trained personnel. Therefore, various combinations of critical factors that may be predictive of CREF have been used to accurately assess VO_2max and/or VO_2AT. Indirect assessment of VO_2max and VO_2AT, using self-perceived intensity(RPE:ratings of perceived exertion) and power output during submaximal cycling exercise as independent variables, is useful when large numbers of subjects are tested. The 12-min walk test at an intensity of RFE 13 also has high potential as a substitute for direct measurement. This manuscript summarizes the scientific rationale and reviews the critical findings of various researches in the area of CREF Measurement.