Fitness instructors routinely use high music volumes that may be harmful to hearing. This study assessed noise levels during 35 low-intensity and 65 high-intensity fitness classes in 1997-1998 and 2009-2011. Questionnaires examined instructors' and clients' preferred music volumes and whether they found loud music "stressful" or "motivating." Noise levels in 1997-1998 and 2009-2011 were similar, frequently exceeding 90 dB(A). Although noise levels in low-intensity classes dropped from 88.9 to 85.6 dB(A), they remained high for high-intensity classes, averaging 93.1 dB(A). In 2009-2011, instructors preferred significantly higher volumes than clients for high-intensity classes. In both time periods, about 85% of instructors found loud music motivating, whereas about one fifth of clients found it stressful. The results suggest that noise exposure from fitness classes, particularly high-intensity classes, continues to pose a potential risk to hearing.