Relationships Of Affect And Exertion To Respiratory Exchange Ratio During Self-Paced Vo(2)Max Testing

Self-paced VO2max (SPV), or Rating of Perceived Exertion (RPE)-based, exercise tests are still relatively new compared to open-ended, externally regulated, exercise tests (e.g., Bruce protocol). The ability to self-select intensity during exercise may have important benefits not yet identified. Furthermore, exertion and affect have previously been identified as separate constructs related to physical activity which may provide insights to exercise intensity. PURPOSE: To measure perceptual indices of both exertion and affect during an SPV and then determine the strength of the correlation of these indices to a physiological index of intensity (respiratory exchange ratio, RER). METHODS: Eleven individuals (4 females; 7 males) completed two cycle ergometer-based exercise tests using an SPV protocol (RPE stage values of 11, 13, 15, 17 and 20) allowing for self-selected intensity to match the requested level of exertion. Exertion (Borg 15-point and Borg 10+ scales) and affect (Feeling scale, -5 to 5) were measured during each stage. Gas exchange was measured continuously with values reported as 15-second averages from the end of each stage, coinciding with measurement of exertion and affect. RESULTS: Linear regression analysis showed a significant relationship between Feeling and RER (p < .001) with a strong effect size (r2 = 0.559) and the following regression equation: RER = -0.036*Feeling +1.033 (95% CI -0.042 to -0.030). Analysis of RPE10+ scale and RER also showed a significant relationship (p < .001) and strong effect size (r2 = 0.725) resulting in the following regression equation: RER = 0.039*RPE + 0.795 (95% CI .035 to 0.044). As RER reached levels that indicated increased anaerobic metabolism (i.e.,1.0), Feeling was reported as a value that was neither Good nor Bad (0, Neutral), whereas RPE10+ was reported as a mean of 5.3 (Strong/Heavy). CONCLUSIONS: Similar to exertion via RPE, affect, via the Feeling scale, is strongly correlated with a change in physiologic intensity, when measured by RER. It appears that combining the measurement of affect with an SPV may enable practitioners to predict certain physiologic phenomenon within ten minutes without the need for metabolic equipment, therefore creating a time- and cost-effective means of determining intensities for exercise prescriptions.