equal to the difference between end diastolic volume (EDV) exercise training does not increase maximal heart rate and, in fact, months of training result in a small de- crease in maximal heart rate. Therefore, all training induced increases in maximal cardiac output must come from increases in stroke volume. Figure 13.1 summarizes the factors that can increase stroke volume in response to endurance training. In brief, an increase in EDV (preload), increased cardiac contractility, or a decrease in total peripheral resistance (afterload) can increase stroke volume. Let's briefly discuss each of these factors relative to the increase in the maximal stroke volume that occurs with endurance training.