Regional development minister Danny Kennedy answered a number of questions relating to water supply, including Exercise Watermill, a mock incident exercise held in October 2011 to stress test Northern Ireland Water's response capacity.

BBC: Question Time: OFMDFM and Regional Development

More study is needed to see how the mental stress test relates to traditional exercise testing, said Dr. Eric Rashba, professor of medicine at Stony Brook University Medical Center in Stony Brook, New York.

CNN: Anger, stress may be linked to heart problems

Researchers then conducted a behavioral test in which participants separately breathed the "exercise" sweat and the skydiving "stress" sweat while judging the emotions conveyed in pictures of faces on a computer screen.

CNN: Sweat may give off stress signals, study says