Sep. 25, 2009 Have you ever sat down to work on a crossword
puzzle only to find that afterwards you haven't the energy to
exercise? Or have you come home from a rough day at the office
with no energy to go for a run? A new study, published in
Psychology and Health, reveals that if you use your willpower to
do one task, it depletes you of the willpower to do an entirely
different task. "Cognitive tasks, as well as emotional tasks
such as regulating your emotions, can deplete your self-
regulatory capacity to exercise," says Kathleen Martin Ginis,
associate professor of kinesiology at McMaster University, and
lead author of the study. Martin Ginis and her colleague Steven
Bray used a Stroop test to deplete the self-regulatory capacity
of volunteers in the study. (A Stroop test consists of words
associated with colours but printed in a different colour. For
example, "red" is printed in blue ink.) Subjects were asked to
say the colour on the screen, trying to resist the temptation to
blurt out the printed word ins