Your Brain and Body on Stress

As your brain is your most important weapon, the effects of physical stress is often underappreciated for its effects on cognition for those who go into harms way, such military personnel, law enforcement, and other groups.
It’s been a generally held belief that cerebral blood flow (CBF) remains relatively steady during exercise, but recent studies (1,2) suggest that’s not the case. CBF appears to depend on a multitude of factors, including exercise intensity. With lower intensity steady state forms of exercise – all things being equal, such as hydration, etc, – CBF may increase, but during high intensity intermittent forms of exercise (like wrestling with another human being in a life or death struggle for example), appears to decrease. This may partially explain the cognitive decline people experience during high intensity exercise.

This information very much applies to law enforcement as it does for the military. Under psychological stress, demand for CBF increases, while supply may decrease, resulting in additional cognitive decline.
If a person has not experienced that cognitive decline under training conditions – and so has some experience and understanding of its effects – the results could prove fatal during a “real life” encounter.
If one has not experienced some job related stress training, they often find even simple directions difficult to follow during their first exposure to it. For example, simple directions regarding which targets to engage in which order, or other simple instructions, fail to happen…

Obviously, this will differ greatly with the persons experience, training, fitness, etc., but it’s well established that physical + psychological stress = decline in cognitive abilities and that’s old news for most and common sense.
The specific effects of stress, physical and psychological, on cognitive abilities is a large and growing topic of interest and research for the military and law enforcement.

Basic take home: some form of stress training, where higher intensity, intermittent, training combined with firearms- hopefully following some job/task relevant movement patterns – will help best prepare those who are likely to face violent encounters that require an ability to function under physical and psychological stress simultaneously.

Additionally, such training will add to an ability to physically deal with the effects of stress and will improve overall fitness and general physical preparedness (GPP) of law enforcement and mil populations.
Most people realize how physical and emotional stress will negatively impact performance, but few make the effort to utilize some form of stress training to help ‘inoculate’ the person to that stress, which could very well mean the difference between life and death in a highly stressful encounter not uncommon to law enforcement personnel.

For example, an article entitled “Assessment of Humans Experiencing Uncontrollable Stress: The SERE Course” by Dr. C.A. Morgan III and Major Gary Hazlett (3) goes into depth on the effects of stress on performance, and the importance of properly applied stress to help “inoculate” the individual to future stressors:

“Physical and psychological stress are unavoidable in military operations, yet the negative effects of stress can make it difficult or impossible for individuals or teams to operate effectively. Stress is an essential element of warfare, and individual responses to combat-related stress have often been the determining factor between victory and defeat on the battlefield.”

“Having recognized the effects of stress, the U.S. military designs its training scenarios to be both rigorous and realistic in their stress intensity. Rigorous training improves a person’s ability to perform on the battlefield, and exposure to realistic levels of stress can protect or “inoculate” a person from some of the negative effects of operational stress. The concept of stress inoculation is very much like the concept of preventing a particular disease through vaccination: When stress inoculation occurs, an individual’s performance will likely be better the next time he is stressed. Like immunization, which occurs only when the vaccine is given in the proper dosage, stress inoculation occurs only when the stress intensity is at the optimal level – high enough to activate a person’s psychological and biological systems, but low enough so as not to overwhelm them. If the stress level is not high enough, inoculation will not occur; if the stress level is too high, stress sensitization will occur, and the individual will probably perform less effectively when he is stressed again.”

The above is focused on the military specifically, but the same principles apply to other professions where a high level of physical and mental stress is likely to occur; such as law enforcement. The correct application of some form of practical job related stress training could pay long term dividends for the law enforcement community.
However, it needs to be designed with the population in mind (patrol LEO vs. Tactical LEO, mil, etc), and correctly applied to that population. Some in the LE tactical community have found my Practical Applied Stress Training (P.A.S.T) is a tool in the tool box that can help there.

(1) J Appl Physiol. 2009 Nov;107(5):1370-80.
Cerebral blood flow during exercise: mechanisms of regulation.
(2) Sports Med. 2007;37(9):765-82.
Regulation of cerebral blood flow during exercise.
(3) 2000 Edition of the The Professional Bulletin of the John F. Kennedy Special Warfare Center and School