A substudy of ghrelin treatment in a multicenter trial previously revealed that administration of ghrelin improves the exercise capacity of underweight COPD patients. To clarify exertional dyspnea more precisely, exploratory analysis was conducted on data from the substudy. Of 20 underweight COPD patients who were randomized to pulmonary rehabilitation with intravenous ghrelin (2 μg/kg, n = 10) or placebo (n = 10) twice daily for 3 weeks in the substudy, 16 (ghrelin = 9, placebo = 7) could be investigated for dyspnea break-point on the dyspnea-ratio (%) of Δoxygen uptake ([Formula: see text]) (= peak minus resting [Formula: see text]) curve. A significant treatment effect of ghrelin on percentage [Formula: see text] at the dyspnea break-point to Δ[Formula: see text] (p = 0.049) was achieved. In conclusion, underweight COPD patients benefitted from ghrelin treatment in terms of shifts to the early exercise phase of the dyspnea break-point during a standardized exercise program.