I had a really awfull year stage 3 adrenal fatigue. Unable to work unable to handle the smallest stress , a game of scrable proved too much . My first cortisol test done 2 years ago when I was maybe stage 2 already showed a low cortisol except morning. The last one I did 1 month ago was winthin range except a bit high at night and in the morning and I was way worse then my first cortisol test.
I was going trough a phase of insomnia so my body might have been rebalancing by producing alot of cortisol during the day I do not know. (another test is on the way)
Anyways I do not think that chronic high cortisol is much better then low and I also think that when dealing with AF you can go from low o high in matter of days. Constant high cortisol is a sign of chronic stress and staying in that stage too long does damage : brain , adrenal etc that eventually will lead to a stage of exhaustion of the body and low cortisol across the board. I believe I go from low to high cortisol in crasch phases depending on the days.