Some scientists have compared patients with chronic fatigue as reminiscent of hibernating bears. It has also been called “post-viral fatigue,” although most times a virus is not identified.

Personally, I have found the debility alarming, serious, and related to the immune system’s goals of protecting us against all invaders.

I also think epigenetic marks such as methylation of histones and RNA-based modifications of gene expression is required for better understanding of the underlying disruptions in the epigenome and gene expression dynamics in chronic fatigue syndrome.

Bringing chronic fatigue syndrome back to the brain, there are other interesting scenarios to consider, including the disruption of the hypothalamic pituitary adrenal axis and the release of the fight or flight hormones (such as adrenalin). This response is disrupted with a muted response to fight or flight hormones in response to stress, resulting in depression in some patients with conditions like multiple sclerosis and breast cancer—patients who routinely have persistent fatigue as well.

There is also an increase of oxidative stress in people with chronic inflammatory disorders such as rheumatoid arthritis and lupus.