Exercise-induced myocardial ischemia triggers the early phase of preconditioning but not the late phase.

The aim of the present study was to establish whether exercise-induced ischemia triggers the second window of protection in 15 patients with coronary artery disease undergoing 2 consecutive treadmill exercise tests and a third test 24 hours later. Our findings confirm that a first exercise-induced ischemic challenge induces the early phase of preconditioning but not the late phase, thus suggesting that either a late protective effect of preconditioning does not exist in the setting of demand ischemia or, if it exists, it must be weaker than the early protective effect.