To be concerned about data privacy in the fitness tracking world is apparently not the question of age or fitness level. It also does not necessarily influence the actual use of fitness tracking technologies. In this empirical study, 590 participants from the EU and USA, who are current users, former users or non-users of fitness tracking applications, were surveyed (online) on their sensitivity perception of several data pieces collected with fitness trackers as well as their data privacy concerns. Furthermore, subgroups of different fitness tracking users were detected based on their different privacy unconcerns.