Learn why students tend to get sick after final exams, in this episode of Gross Science from NOVA. Research has shown that people who slept an average of less than seven hours a night in the weeks leading up to an exam were almost three times more likely to get sick. Stress can also have a huge effect on our health, lowering the activity of cells that help fight viruses. In addition, traveling right after exams can result in contact with many different pathogens. In all likelihood, a post-exam cold probably comes from a combination of these factors—plus others like poor diet, lack of exercise, and the time it takes a particular pathogen to start replicating. This resource is part of the NOVA: Gross Science Collection.