The article describes "stunning", or "myocardial post-ischemic dysfunction". An animal model is presented to introduce the characteristics of the phenomenon, and data from a clinical trial are referred in order to demonstrate the clinical relevance of stunning. The long-standing lethargy experienced by many patients with coronary artery disease several hours after exercise may be caused by stunning. It is necessary to know the phenomenon in order to realize why myocardial contractility may be temporarily reduced, not only during but also after ischemic episodes.