Warm-up exercise can significantly reduce the severity of myocardial ischemia on exercise after a 10-minute rest, but this benefit is significantly less after a 30-minute rest. Further study is needed to clarify the mechanisms responsible for warm-up. The results of this study are consistent with a change in myocardial metabolism similar to ischemic preconditioning or a delayed increase in myocardial perfusion to the ischemic territory, which has returned toward baseline after 30 minutes.