What is Fatigue?
The fatigue caused by stress is understandable when you realise that the body’s fight or flight mechanism ultimately becomes activated for long periods, sometimes semi-permanently. For a person with a regular daytime job, and there is stress attached to it, the activation can last from Sunday evening – at the prospect of having to go to work the following day – through to the following Saturday morning – at the prospect of two days relief.
The fight or flight mechanism is designed to operate briefly and intermittently, but when activated for abnormally long periods, causes the body’s physical, mental and emotional batteries to drain dry. Energy stored in the body as protein, glycogen and triglycerides is rapidly converted back to amino acids, glucose and fatty acids etc to help the body deal with the perceived threat. The process of conversion, achieved via the release of stress hormones such as glucocorticoids, glucagon, epinephrine (adrenaline) and norepinephrine (noradrenalin), itself consumes energy. The stress hormones also trigger the conversion of protein in those muscles not required for flight or fright into amino acids.
Whilst the human body is capable of withstanding considerable levels and periods of stress, when the stress response is turned on for long periods, the body inevitably sustains damage through excessive depletion of energy reserves, resulting in fatigue, loss of strength and stamina, muscle wastage (as in steroid myopathy when patients receive large doses of glucocorticoids to treat various illnesses), and adult-onset diabetes.
At the weekend and days off, the weakened immune system cannot fight off viruses (eg colds, flu, glandular fever etc) and the person suffers constant illnesses during which the batteries do not recharge. Even without viral infection, the obsessiveness and disturbed sleeping patterns prevent the body from replenishing stored energy. Reactivation of the fight or flight mechanism prior to returning to work produces a flow of stress hormones which appear to temporarily suppress the effects of illness.