Randomized-order phasic distentions were then applied at 16, 24, 30, and 36 mmHg above the operating pressure to measure the sensations of gas and pain. Each distention lasted 1 minute and was followed by an equilibration period at the operating pressure for 2 minutes. A 100-mm visual analog scale (VAS) was used to assess the rating of arousal and stress experienced by each participant before performing the phasic distentions. During the distentions, participants also used the 100-mm VAS to rate the intensity of gas and pain perception at 30 seconds from the start of the distention.