Progressive values are substantially endorsed across Western Europe, yet concrete engagement with systemic social change remains limited. This gap raises questions about the motivational and physiological processes that may underlie ambivalence toward progressive action. Drawing on the biopsychosocial model of challenge and threat (BPS-CT), the present study examined whether progressive systemic change elicit cardiovascular threat responses even among progressive individuals who verbally support such change. Ninety Western European university students participated in a within-subjects laboratory study in which they discussed the university’s current collaborations (status quo condition) followed by implementing an academic boycott targeting unethical institutional collaborations (social change condition). Cardiovascular responses were assessed via cardiac output (CO), total peripheral resistance (TPR), and the Threat–Challenge Index (TCI), and analyzed using multilevel modeling. In line with preregistered predictions, the social-change condition elicited stronger physiological threat than the status-quo (lower or stable CO, higher TPR, decreased TCI). These responses persisted after controlling for political orientation and (progressive) attitudes, and despite participants generally expressing high support for social change. Exploratory analyses revealed heterogeneity in the sources of threat: Participants either showed reluctance to relinquish status-quo privileges or voiced practical concerns regarding the change. By contrast, relative challenge, which was overall less prevalent, related to perceiving collective resources to deal with the change but also to rationalization of opposition. These findings suggest that even progressive individuals are not always immune to threat responses when confronting concrete systemic change. The results extend the BPS-CT by highlighting the importance of engaging with, rather than avoiding, threat in contexts where social transformation is inherently destabilizing and uncertain.