The immune system's job is to identify threats to the body and fight them off, but it doesn't always pick the right targets. (newatlas.com)
Cortisol secretion is triggered when there is a perceived threat to the body, such as: (innerconnectedwellness.com)
Continually training in this state becomes a survival threat to your body because our anaerobic (glycogen fueled) energy pathway is what our body turns to in those fight to the death type scenarios. (drrosedale.tenderapp.com)