Chronic stress is ruining my memory and focus

I started doing 20 mins of cardio every morning and the brain fog lifted significantly after a few weeks.

Chronic stress does not cause permanent "brain damage" in the way we typically think of it, but it profoundly affects brain architecture. Sustained high levels of cortisol (the stress hormone) can shrink the hippocampus (responsible for memory and learning) and enlarge the amygdala (the fear center). This explains your brain fog and memory issues. The good news is that the brain is highly neuroplastic. Practices like Mindfulness-Based Stress Reduction (MBSR) and regular aerobic exercise have been shown in MRI studies to physically thicken the hippocampus and restore cognitive function over time.