What you say—and what you do—counts. If you eat well, exercise regularly, and take good care of your own health, it will have an influence on him, macho man or no. Researchers recently looked at data from 6,072 married individuals to determine the degree to which a person's health habits—smoking, drinking, cholesterol screening—are influenced by their spouse. "We consistently find that when one partner improves his or her behavior, the spouse is much more likely to do so too," says Jody Sindelar, health economist and public health professor at the Yale School of Public Health. "This is found across all the behaviors analyzed—including something as simple as getting a flu shot."