Supplemental material for corresponding manuscript, containing the following: 1) Supplemental Figure 1 (Experimental Design); 2) Supplemental Figure 2 (Metabolic and Heart Rate Responses to Steady State Exercise); 3) Supplemental Figure 3 (Ventilatory Equivalents for O2 and CO2 during Steady State Exercise); and 4) Supplemental Figure 4 (No Significant Change between the Magnitude of Ventilatory Long-Term Facilitation and Change in Exercise Gain.