Figure 2.

Schema of the time course of acute stroke. In the ischemic brain, neuroprotective factors increase during the early phase from a to b (phase 1). The level of protective factor expression peaks from b to c, the therapeutic time window (phase 2). Preconditioning exercise increases intrinsic protective factors in the penumbra region and may extend the therapeutic time window by enhancing the expression of intrinsic protective factors (from c to c'). During phase 3, the level of protective factor expression reduces. In this phase, post-stroke rehabilitation is important to enhance brain plasticity and functional recovery for stroke survivors.