Why is cortisol's permissive effect on catecholamines and glucagon upon secretion during stress important in the human body?

It is essential for survival when stress is severe.
In severe stress, cortisol stimulates the breakdown of protein and fat through the process of gluconeogenesis. Glucagon aids gluconeogenesis. Protein is broken down into amino acids and then to glucose. Cortisol facilitates the action of glycogen phosphorylase which is needed for epinephrine to have an effect on glycolysis.

Catecholamines also cause bronchodilation, vasoconstriction which is seen in severe stress. Cortisol is needed for a permissive effect on catecholamines and glucagon. Without cortisol, it would be difficult to survive in severe stress.

Essential for survival when stress is severe-glucocorticoids (cortisol) stimulate protein catabolism > liver uptake of amino acids > conversion to glucose (gluconeogenesis) **anti-insulin action on muscle (own local supply) & adipose tissue (inhibit uptake of glucose) increase glucose supply to brain tg breakdown > glycerol + fa (fuel for muscle activity) increase plasma aa, glucose, glycerol & fa permissive effects (gives permission) for: -catecholamines (vasoconstriction, bronchodilation, lipolysis) -glucagon (gluconeogenesis) antiallergic effect increase rbc count increase neutrophil count due to the permissive actions for catecholamines & glucagon, secretion of acth & glucocorticoids (cortisol) are essential for survival when stress is severe.