Cardiopulmonary exercise testing as an integrative approach to explore physiological limitations in Duchenne muscular dystrophy.

Background: Cardiopulmonary exercise testing (CPET) is the gold-standard for quantification of peak oxygen uptake (VO) and cardiorespiratory and muscle responses to exercise. Its application to Duchenne muscular dystrophy (DMD) has been scarce due to the notion that muscle weakness inherent to disease restricts the cardiorespiratory system from reaching maximal capacity.

Objective: To investigate the utility of CPET in DMD by 1) establishing whether patients can perform maximal-effort exercise for valid VO peak assessment; 2) quantifying VO peak repeatability; 3) characterizing muscle and cardiorespiratory responses; 4) comparing VO peak to 6-min walk distance (6MWD).