The U.S. Department of Health and Human Services has issued new fitness guidelines that recommend adults get two and a half hours of moderate exercise every week, at a minimum. The slogan of the new guidelines is "move more, sit less," in an attempt to address the two main reasons many of us don't get enough exercise. This new guidance is the first update to the guidelines since 2008, when they were first released. Here are the report's main suggestions: Adults At least two and a half hours of "moderate-intensity aerobic" exercise a week. Exercise should be done in intervals…