Self-Control Is A Resource, Ctd

Psychologist Roy Baumeister explains how the body's energy supply affects decision-making:

We've begun to learn about mind-body interactions — why self-control might deteriorate during premenstrual syndrome and how it may also interact with the immune system, which sometimes uses plenty of glucose when fighting off a disease. That's why people may become cranky and irritable when they have been exposed to a cold: The immune system is using up the glucose so it's hard to be patient!

An earlier look at the mechanics of willpower here.