"decrease in cortisol" is not good for some people. Overly low cortisol was a feature of my severe bout with hypoglycemia - and I believe can be a contributor to the hypoglycemia problems of others. Adrenals make cortisol, and if they are exhausted, cannot make enough - the opposite problem from that of the average person.
Just wanted to note that - in case people with adrenal issues see this thread.