Being submitted to dialysis four hours a day, three times a week can mean experiencing boredom, besides discomfort. Patients often report that the time seems to take longer to go by. The purpose of this study was to explore the influence of two different musical rhythms in the states of mind and perception of adult patients undergoing dialysis, since the literature on this subject is scarce. The study was performed at a private hospital with 43 patients, who participated in two sessions of musical improvisation with a keyboard. The subjective states and perception were evaluated before and after the intervention. Over 80% of the patients felt that time went by faster after the interventions in both rhythms. However, the pace was a decisive factor in the kind of emotional experience that the patients had.