I've heard they use cognitive exercises among intensive exercise.

This article is great: 21 Proven Ways to Increase Brain Blood Flow — Optimal Living Dynamics

Also, Dr. Kharrazian's book (carrick trained but more focused on the nutrient/diet/supplemental side of healing brains) is nice for increased brain blood flow. He talks about vinpocetine, huperzine a, gingko, and a few others.

He also mentions brain fog as indicating brain inflammation. Catechins from tea, passionflower extract (baicalein), curcumin from turmeric, resveratrol, luteolin, and apigenin were his recommendations for brain inflammation in that book.

I too have significant brain fog and those hypoglycemic crashes. It is significantly better when avoiding processed foods, in particular the grain-based ones. Fasting, light to moderate exercise, vitamin C, niacin, and NAC.

Also, infrared light (I have a $40 unit) is incredible across all boards for my brain.

I had a buddy diagnosed with POTS about five years ago.