Cognitive reserve (CR) is characterized by the ability to engage neural networks for adaptive reorganization of brain functions in response to damage or stress. This study aimed to identify the structural and functional organization of neural networks in patients with chronic cerebral ischemia (CCI) having different CR. The study involved 137 women aged 50–85 years suffering from CCI without diabetes. The average duration of CCI was 10.1 ± 0.7 years. CCI patients were divided into two groups: with secondary (SE) and higher (HE) education. Salivary cortisol levels were measured before and after cognitive load, along with the differences in brain connectivity organization based on fMRI data in two patient groups. Connectivity patterns were primarily found in the auditory areas, different in two groups after applying multiple comparison correction (FDR) and were responsive to cortisol levels. Patients with greater CR developed CCI later, showed significantly more positive connectivity values, had lower baseline cortisol levels, and displayed larger shifts in cortisol levels during cognitive load.