Two experiments examined the joint impact of self‐focused attention and task difficulty on performance‐related cardiovascular reactivity. Predictions were derived from an application of the principles of motivational intensity theory and its integration with the active coping approach to performance conditions that have consequences for self‐esteem. According to this model, self‐focus will induce a state of self‐evaluation and thus augment the importance of success, and cardiovascular reactivity will increase with difficulty until a task becomes impossible or the goal is not worth the necessary resources. Supporting these predictions, 2 experiments found that high self‐focus increased performance‐related systolic blood pressure reactivity when difficulty was unfixed (“do your best”) or fixed at a high level. When the task was easy or impossible, however, high self‐focus did not affect systolic reactivity relative to low self‐focus.