The perception of discomfort in interval training is not always a reliable indicator of exertion, as some evidence suggests people do not find very short, hard efforts as unpleasant as commonly believed.

“It's too simplistic to just go, well, sprint type training, no one's going to do that because it hurts because now there's evidence to show that, well, actually it doesn't. When people rate this, they don't find it as unpleasant, as uncomfortable as some make it out to claim that it is.”