Your best defense this cold and fu season may be in the gym. Re- searchers at Appalachian State Univer- sity report that people who exercise more-as well as those who rate them- selves as highly ft-are less susceptible to upper-respiratory-tract infections. The study followed 1,002 adults over two 12-week periods in the fall and winter. Based on self-reported exer- cise, those who work out at least fve days a week suffered 43% fewer days with respiratory infections than those exercising no more than once a week. The one-third who rated their own ft- ness level the highest experienced 46% fewer sick days than the least-ft group. Even when they did get sick, frequent exercisers and the most ft suffered less- severe symptoms. Scientists suggested that even though the immune system returns to pre-exercise levels within a few hours, each workout may provide protection against pathogens that make the respiratory system vulnerable to infection. Other studies have actually shown that exercise may acutely sup- press immune response; this study may refect the effects of defensive responses over time. British Journal of Sports Medicine, online before print; abstract at <http://dx.doi.org/10.1136/ bjsm.2010.077875>
