For me, brain fog, aka cognitive impairment includes: Confusion, trouble concentrating, problems remembering things, word retrieval issues, and more. What helps is approaching it from all angles: prioritizing good sleep, good nutrition, drinking enough water, movement/activity, managing stress, cognitive-behavioral techniques, and rest (not just sleep). I also have to pick and choose wisely what I'll use my precious energy on and how to conserve it. This includes emotional and mental energy.

Try cold showering

Heat helps me is making lists. 🙃