In some cases this could be a diagnosable and treatable cause of the kind of illness that often gets described as "adrenal fatigue".
I have some experience with this topic, having spent at least 13 years in that category of people who is ill in a way that mainstream medicine can't really diagnose or treat - and in a way that has parallels with the symptoms described in this article (though not nearly as severe or debilitating).
The idea of "adrenal fatigue" and "adrenal insufficiency" has come up a lot in the self-directed research I've done, but only among complementary/alternative practitioners like naturopaths and chiropractors.
It's not really a medical way of thinking about things - i.e., "your adrenal glands must be tired because you've been too busy/stressed". It's not something you can test for or address with medical treatment - which is why people who go down that path end up undertaking 'holistic' treatment approaches like diet, supplements, exercise, emotion-based therapies, etc, with varying degrees of success.
But there are plenty of people I've come across, particularly in communities of people who diagnosed with, or presumed as having "Chronic Fatigue Syndrome", who suffer without any improvement for many years despite trying every conceivable remedy, whose condition may well be explained by what is described in this article, or by something comparably obscure, relating to the adrenals or other parts of the autonomic nervous system.