Chapter 5: Training for Endurance 111 prescribe exercise intensity that some individuals would be undertraining while others would be overtraining. Figure 5.3. Accuracy of the Age-Predicted Maximum Heart Rate (APMHR) Equation As a result of the limitations associated with MHR, other methods are often used for accessing exercise intensity including rate of perceived exertion (RPE) and the talk test. The RPE is a quantitative measure of how an individual perceives exertion during physical activity. The talk test is another easy way to estimate exercise intensity. For example, exercise is classified as moderate-intensity if an individual can talk, but not sing, during the activity. As demonstrated in Table 5.12, research shows a strong collection correlation between MHR, RPE, and the talk test (U.S. Navy Command Fitness Leader Course, n.d.). In other words, if you do not have the ability to measure your MHR or access to a heart rate monitor, using RPE or the talk test is an easy and reliable means of monitoring exercise intensity.