Combat Stress Response & Tactical Breathing

May 20, 2014

On Combat by Dave Grossman (2008)
On Combat by Dave Grossman (2008)

I recently finished the book, On Combat: The Psychology and Physiology of Deadly Conflict in War and in Peace, by former Army Ranger turned psychologist, Lt Col (ret.) Dave Grossman.  Although I have some concerns on how rigorous the science is behind most of the books precepts, the general concepts I found highly applicable to a variety of disciplines.The book is clearly written to an audience of infantry troops, special forces, police officers and SWAT members.  However, much of the supplied information is easily applied to combat performance in modern fighter pilots. On Combat educates the reader on the body's expected response to combat stress and then proceeds to offer strategies for performance optimization during combat. If you can find the time outside of flying, debriefing, mission planning, and queep to read the book, I highly encourage you to do so. If not, here is a summary with modifications for an audience of combat aviators.


Obviously, it is critical to understand and expect that particular inputs to flight controls will lead to predictable responses by your aircraft.  Similarly, you must understand your body's triggers and expected responses to a variety of situations. In both cases, combat only serves to magnify the consequences of any lack in self-awareness.Some of you have fought or dropped in combat. For you, descriptions of the body's response to these stressors may sound similar. Many  have only flown in exercises, surges, or complex flight upgrade sorties. No matter how high-fidelity the simulated training environment is, you will not be able to fully predict your body's response to a real-world combat sortie when your life is seriously threatened by a real adversary fighter or SAM. Knowing what to expect and how to control these responses before the fact may save your life.

The Autonomic Nervous System (ANS)
The Autonomic Nervous System

The Autonomic Nervous System (ANS)

The human body operates under direct control from two separate, but connected nervous systems - the somatic and the autonomic systems. Your somatic nervous system is made up of nerves running to and from sensory organs to your brain and back to a variety of muscles, which you voluntarily control thru intention. The ANS, however, is like your auto-pilot. This nervous system also relays sensory information to your brain, but the responses happen automatically without direct control from the end user (you).  Bodily functions controlled by the autonomic nervous system include heart rate, breathing rate, changes in blood vessel size, blinking, change in pupil size, sweating, shivering, and pretty much everything that your digestive system does. Breathing rate and eye blinking can also be closed voluntarily.  Take note - this will have important implications as stated below.The ANS is divided into two (technically three) sub-categories: the sympathetic system, often considered the Fight, Flight, & Freeze system and the parasympathtics, often called the Feed & Breed nervous system.  When the sympathetics are aroused, massive amounts of adrenaline hormone spills into the blood stream.  Your body responds to this hormone by breaking down and utilizing carbohydrates, increasing cardiac output/heart rate, respiratory rate, and blood pressure (preparing your muscles for maximum energy expenditure).  Additionally, your pupils open wider and your GI system usually slows down, stops, or in some extreme cases completely spins out of control.  This is your body's natural 'Go-Pill'.

Poopie Suit
Poopie Suit

Loss of Bowel & Bladder Control

A perception of imminent threat to your life causes an extreme sympathetic surge and parasympathetic inputs are almost imperceptible.  The body devotes almost all resources to primitive survival actions.  In this setting, it is normal for the body to lose control of bladder and bowels.  According to a survey quoted by Grossman in the book, in World War II 25% of ALL U.S. soldiers admitted to peeing their pants while 12.5% admitted to pooping their britches (pants of the 1940's).  This statistic includes all soldiers in the war.  When only soldiers seeing direct combat were isolated, these numbers are actually considerably higher.  Similar surveys among SWAT and police officers find that this happens much more commonly than reported.

  • Take a 'Battle Crap' before an important sortie, especially real-world combat sorties.  Most SWAT and Special Forces guys are aware of this phenomenon and build this into their preparation for a mission.  This clears the lower GI tract and reduces likelihood of fecal evacuation (shitting self) in combat.
  • It's important for you to understand that this is a normal physiologic response when one's life is seriously threatened. It has absolutely nothing to do with courage or lack thereof.  You may someday return from a real-world combat sortie and find that your Poopie Suit literally lived up to it's name.  Don't be embarrassed, this is normal.  Yes, you've been hostily-renamed, but the call sign 'POOPIE PANTS' does have a certain ring to it!!

Parasympathetic Backlash

Experiencing a sympathetic surge utilizes a great deal of the body's energy reserves.  Following an event in which your 'Fight or Flight' response has been rocking for hours, you are at significant risk of crashing from exhaustion.  The sympathetic system shuts down and is replaced by inputs from the parasympathetics.  Be prepared for this to happen.  If you are still in the fight and things get sporty again, you may find that you are behind the jet with a horrible G-tolerance due to parasympathetic backlash."The moment of greatest vulnerability is the instant immediately after victory." ~ Napoleon Bonaparte

  • Even after a successful combat sortie, you need to be aware that you're on your game until wheels hit pavement.  Understand and identify this response.  Be sure to mitigate for it in-flight when experienced.

Adrenaline Dump

The duration that adrenaline hormones stay in your body is fairly short after production.  However, after a significant surge, if the time in combat is short and conclusive, you may have a surplus remaining and feel agitated and anxious upon landing.  This could even significantly affect your sleep that night.* If you suffer from adrenaline surplus after a particularly difficult sortie, you may need to 'dump' it by engaging in additional exercise followed by a long shower until you feel the agitation dissipate.


Grossman has a long discussion on the importance of sleep and its obvious and measurable effects on performance degradation.  I have already written extensively on the importance of sleep for safe, effective flight operations.

  • The body's normal physical and emotional response to combat may cause disruptions in sleep.  Being prepared mentally will increase your chances for full restorative sleep.  See  Combating Fighter Pilot Fatigue for more info.


This may be the most applicable part of the book for warriors across the spectrum.  So, listen up.Goldman describes 5 Conditions that a warrior may experience in combat.  Each condition occurs within a particular heart rate range (HR) and is associated with predictable changes in performance.  During combat, it is crucial to know in which condition you are operating.  Only then, can you begin to intentionally control your physiologic responses and perform at your maximum ability.Grossman's 5 conditions of physiologic readiness provide a spectrum from the resting Condition White thru the near-incapacitating Condition Black.  The associated heart rate is important as it provides an objective measure of one's condition and also provides a fairly simple explanation for why performance potential will change during different conditions.  Increased heart rates due to fear or stress are physiologically different than exercise-induced changes, although in the presence of increased activity they can be magnified.  When one's heart rate reaches a certain threshold, the chambers of the heart receiving deoxygenated blood are not able to fully fill and cardiac output will begin to diminish.  When you exercise, your blood vessels usually dilate allowing more blood into your muscles and certain organs.  During times of life-threatening stress response, the blood vessels do the opposite, constricting, which increases blood pressure and starves many muscles of critical oxygen.  Goldman theorizes that this response is evolutionarily adapted to protect warriors from large hemorrhages by shifting blood to the body's core, creating a type of natural armor shell near the skin surface.  Relevant to the fighter pilot is a vasodilatory response that seems to occur after the life-threatening trigger is removed.  This causes the blood vessels to open simultaneously, but the effect on a pilot's G-tolerance should be clear.  Directly following a close-call in which your life was threatened and you feel significantly shook up, stay away from high-G maneuvers if at all possible until you feel recovered.The desired condition for performance optimization depends on the activity that a warrior is engaged in.  The key to Grossman's research though, is that with training and awareness of the physiologic readiness conditions, one can exert some control over their physiologic state.  This is where you can increase the odds that your bomb lands on target or you get the BFM kill over your adversary.

Conditions of Physiologic Readiness
Conditions of Physiologic Readiness
  • Conditon White:  The Warrior at Rest. (Normal Resting HR)
  • Condition Yellow:  Psychologically Prepared for Combat.  Fighter Pilot Ready. (Resting HR - 115 bpm)
  • Condition Red:  Optimal Warrior Survival - Gross Motor Skills, Visual Reaction Time, Cognitive Reaction Time Peak at expense of fine motor skills. (HR 115-145 bpm)
  • Condition Gray:  A Transitional Phase between Condition Red & Black, which may be modified with training.  (HR 145-175)
  • Condition Black:  Catastrophic Breakdown of Mental & Physical Performance. (HR > 175)

Since Grossman writes primarily to an audience of special operators, police officers and SWAT personnel; he encourages these warriors to reach and maintain Condition Red during combat.  Although reaction times and gross motor skills seem to peak in this Readiness Condition, it comes at the expense of fine motor control.  This is NOT where the professional fighter pilot wants to be for a majority of in-flight operations.  Instead,  the fighter pilot’s required combat skill-set is much more suited to Condition Yellow where fine-motor control is maintained.  Once the HR climbs from 115 -145 bpm, fine motor control begins to be rapidly lost and the pilot’s ability to make simple inputs into their avionics, radar, and combat technologies degrade.  Shoot for Mellow Yellow!  Maintain your HR below 115-120 if at all possible, or thru intentional training learn to extend Condition Yellow (fine motor control) into greater heart rates.

Owen Wilson in Behind Enemy Lines
Owen Wilson in Behind Enemy Lines

There are times when a fighter pilot will actually want to enter Condition Red.  During and after a bailout situation, Condition Red and stretching Condition Gray will be necessary.  This is even more important if you were to bail out into enemy territory and had to evade.  The key in this situation is PREVENTING Condition Black.  In this setting, fine motor control will not be as important as the added benefits that Condition Red allow- increased visual and cognitive reaction time, athletic surge, and increased gross motor skills.  It is now time to survive.  Your SERE training actually uses Grossman's technique of stress inoculation to prepare you for this exact scenario.Grossman later quotes research that show thru specific training strategies (see below), warriors can maintain peak performance at heart rates usually into the next Readiness Condition.  The studies he quotes demonstrate maintenance of Condition Red into increasing heart rates that define Condition Gray.  This is where the combat professional needs to be training.  Stress inoculation leads to stress acclimatization.  Tactical breathing allows the warrior to voluntarily lower the heart rate and optimize performance. These will be covered in more detail below.


During times of extreme stress, the body's sensory and cognitive equipment may not behave in the same way that you are used to.  As one enters Condition Red, Gray, and ultimately Black; your body devotes more and more of its limited resources to the most basic survival mechanisms and parts of the brain.  As a consequence, many perceptual distortions have been reported by those frequently operating in life-threatening environments.  Below are some of the most commonly described examples of this phenomenon.

  • Diminished Sounds (Auditory Exclusion)
  • Intensified Sounds
  • Tunnel Vision
  • Heightened Visual Clarity
  • Temporary Paralysis
  • Slow-Motion Time
  • Fast-Motion Time
  • Memory Loss for some or all of Events/Actions
  • Memory Distortions
  • Intrusive Distracting Thoughts
  • Dissociation (Detachment)


The more you swath in training, the less you bleed in battle. ~ Irwin Rommel

Unified-Stress Performance Model
Unified-Stress Performance Model

Stress Inoculation

The military makes good use of this valuable training strategy from basic training through specific job preparation.  As a fighter pilot, this is your life.  When you're not deployed flying combat sorties, you are training to do so.  Through the exposure of stressors that simulate real-world combat, you become better prepared to physiologically remain calm and collected when the real threats exist.  If you can maintain Condition Yellow during training, you will be much more likely to do so in combat. The SERE training you have experienced prepares you to the extreme stressors of the rare, but realistic possibility of bailing out in an enemy territory teaching you not only the skills of survival, evasion, resistance and escape; but also the mental toughness.  The word, inoculation, comes from vaccine technology.  By exposing one's body to manageable volumes of germs, the body can build up a long-lasting immunity to the real threat of that disease.  An exposure to controlled amounts of stress does quite the same thing.

Stress Acclimatization

This phenomenon develops via the process of Stress Inoculation described above.  The human body has an amazing ability to adapt and acclimate to a variety of unique conditions.  Physiological changes occur allowing climbers to acclimate to the low oxygen densities encountered on Mount Everest.  Long distance ultra-marathoners acclimate to extreme heats allowing races across the Saharan Desert.  Similarly, thru increased stress inoculation, the body acclimates and becomes conditioned to perform optimally even during times of extreme stress.  As your training proceeds from initial pilot training, to aircraft-specific training (B-course in the USAF), various upgrades and weapons school; stressors intentionally increase in a controlled fashion to make you better.  This is stress acclimatization.  The key is to provide the most high-fidelity training possible.  Upgrade sorties, local inspections, and large military exercises like Red Flag do a good job of replicating real-world threats, but you may still have uncertainty of how your body will react when a real SAM is launched at your aircraft.

  • Understand that although you are HIGHLY acclimated tothe in-flight stressors of combat, until you are exposed to these life-threatening weapons in combat, there exists some uncertainty of how your body will react.  Train with this in mind and consider which condition your body is operating from when exposed to training threats.

The Debrief

Pilots have almost perfected the debrief.  Many other operators on the ground do not do this as well or as frequently as pilots.  Obviously, this is where the real learning of tactics and the opportunity to improve occurs.  In On Combat, Grossman discusses the importance of discussing one's emotional and physical reactions to stressors during debrief.  I have sat thru enough fighter debriefs to know this does not frequently occur.  Although, most sorties will pass without a serious mishap or life-threatening occurrence, there are often times when things go wrong and a near miss occurs.  Aside from just discussing what broke down tactically to allow this to happen, it is also important to discuss how you responded to this threat.  Did you feel yourself momentarily lose control?  Were you hyperventilating?  Were you hands shaky?

  • Debrief physiologic responses to both real-world and simulated threats.  In the event of a near-miss one's response to fear should be evaluated verbally and a discussion of how the response can be improved in the future should take place.  Which Condition were you operating from?


Tactical breathing is a technique to control your self-regulated sympathetic (Fight, Flight, Freeze) response.  As mentioned above, the only two responses of the ANS that you can control is your breathing rate and blinking of the eye.  Special Ops personnel have to demonstrate tactical breathing in their training by intentionally slowing their heart rate from a stress-induced high to a normal resting rate within a few minutes.  Controlling cardiac output with breathing should come easy to a fighter pilot, as the Anti-G Straining Maneuver (AGSM) does the same thing, but in this case to maintain blood perfusion of the brain and prevent G-LOC.There are two instances where this technique could be useful to a fighter pilot.  In the first case, you may find yourself in-flight and moving from Condition Yellow to Red, Gray, or Black.  If you begin to tremble and find that although you are mentally vigilant and responsive,  you are losing your fine motor control, you need to get your HR down and re-establish Condition Yellow.  If you suffer such a close call that you are literally incapacitated by fear, you will need to bring your HR down from Condition Black at least to Condition Red, then Yellow so that you can fly the jet safely.  The setting in which a pilot is more likely to enter incapacitating Condition Black is after a bailout.  This is due to the relatively infrequent training for this scenario.  Although, a pilot always knows this is a possibility, it is common for one to go an entire career without an ejection.  Due to the significantly less specific stress inoculation, you are at risk of losing control of your physiologic response in this setting.  Use tactical breathing to reassert control of the overwhelming sympathetic response.Although the actual ideal frequency and duration of the breaths require further research, Grossman teaches a 4x4x4 technique.

  1. Breath in through nose for a slow 4-count.
  2. Hold breath for a slow 4-count.
  3. Breath out through the mouth for a slow 4-count.
  4. Hold breath for a slow 4-count.
  5. Repeat cycle 4 times.

Practice this technique out of the jet first, just like you should practice your AGSM in the 1-G environment until it becomes habit.  See the youtube video below for additional explanation and a demonstration of this technique.



1. On Combat: The Psychology and Physiology of Deadly Conflict in War and in Peace (2nd ed) by Loren W. Christensen Dave Grossman.  Warrior Science Group Inc (August 28, 2008).

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