Working out before you get your flu shot may help you get better results. In a study of 60 college students, the women who worked out by lifting weights 6 hours before receiving their flu shot developed more antibodies over the following 5 months than the women who didn't do any strength training. And the men who lifted weights had a greater cell-mediated response over the following months, but didn't have any more antibodies.

Why the difference between men and women? Researchers aren't sure, but with this in hand they are sure now that exercise stimulates antibody production, and that they've got a good start on finding simple things people can do to boost vaccination results.