For researchers, there are many advantages to doing studies on volunteer athletes. First, most athletic programs require a physical exam. This provides researchers with "baseline" or starting information that isn't always available for the general population. Second, working with college athletes gives researchers access to large numbers of volunteers. Finally, college athletes are more likely to comply with research requirements. In other words, if 30 to 45 minutes of exercise is required every day, this group is more likely to do it.

Making exercise recommendations based on young, athletic adults gives us a "best case scenario." That is, healthy, active adults who follow this advice are more likely than the general population to have good outcomes. That isn't to say older, less active adults won't benefit from these recommendations. The effects may simply take longer to achieve.