Dyspnea and pain share many features. One of them is the counterirritation phenomenon: defined in pain research as the attenuation of one pain by another pain. Dyspnea induced with inspiratory threshold loading (increased sense of work/effort ) has been shown to attenuate electrical pain as shown through nociceptive flexion reflex inhibition, or thermal pain, as measured with cortical evoked responses (laser evoked potentials-LEP).