What does it mean to cooperate? How do we share meanings and actions in order to reach a common goal? In this paper we explore the relation between cooperative coordination and heart rate. We argue that in cooperative contexts participants synchronize their heart rhythms according to two factors: the affordances of the task at hand and the gradual consolidation of collaborative practices. Six groups of participants were instructed to construct LEGO models of six abstract notions (“responsibility”, “knowledge”, “justice” etc.), both individually and in groups. We combine video analysis and heart rate measurements and employ recurrence analysis techniques to quantify the mutual adaptability of heart rates among the participants in the different tasks. We show that during individual tasks individual heart rates synchronize both within and between groups (but not with controls) plausibly due to the affordances of the task at hand. We also show that during collective, but not individual tasks, within group synchronization grows over time. Finally, we discuss how these measures of synchronization relate to the participants’ engagement in the tasks at hand and to the end products (LEGO models) of their joint activity.