One of the most acrimonious arguments in the self-defense community is whether competition is good or bad for the tactical SD minded practitioner. The anti side will say that no sport can replicate the stress of real life combat so therefore it is useless and a waste of time. Unfortunately, the ones who argue this are wrong.
What they fail to realize is that the chemical make up that causes our body to feel stress does not change. Regardless of what stressor there is, the hormonal cocktail consists of the same things whether the stressor is someone trying to kill you or worry about financial natters.
From WedMD – “your bodies react the same to stressors.”
And from Medicine.net – “scientists understand much about how the response to stress works. The two main systems involved are the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). (These systems are described later.) Triggered (activated) primarily by an area in the brain stem (lowest part of brain) called the locus coeruleus, the SNS results in the secretion of epinephrine and norepinephrine.” And “The HPA axis is a grouping of responses to stress by the brain and the pituitary and adrenal glands. First, the hypothalamus (a central part of the brain) releases a compound called corticotrophin releasing factor (CRF), which was discovered in 1981. The CRF then travels to the pituitary gland, where it triggers the release of a hormone, adrenocorticotrophic hormone (ACTH). ACTH is released into the bloodstream and causes the cortex of the adrenal gland to release the stress hormones, particularly cortisol, which is a corticosteroid hormone. Cortisol increases the availability of the body’s fuel supply (carbohydrate, fat, and glucose), which is needed to respond to stress”
This occurs in some form of EVERY stress event, period. The body does not know the difference between a life threatening action such as a violent criminal assault and a fear of losing a job.
In other words, if you feel stress in a competitive event, you are feeling the same type of chemical response that you feel in fight for your life. So if you want to argue that competition is bad and/or useless, that is all well and good, but you absolutely cannot say it is dissimilar to combat. Because to your body, it is. The medical and clinical evidence is settled science.