Your Parasympathetic Response
Your parasympathetic nervous system is responsible for getting you back from your high state of arousal, allowing your cognitive functions to come back online, your digestion to resume functioning, and lowering your breathing and heart rate to more comfortable levels. Clearly, when we are in conflict or negotiation, this is a much-preferred state to be in.
The Vagus Nerve
However, there is one response that is governed by the PNS, specifically the vagus nerve, that can really throw you off. When we sense threat, one branch of the vagus nerve (the dorsal vagal branch), sets us up for a very primitive protection response. This is one of the oldest responses that we have and which we often see in animals who are on the verge of being eaten by a predator: playing dead.
Playing Dead
Depending on the acuteness and level of the threat, as well as the general state of our nervous system, this response can vary between mental and emotional disconnection from the social environment to a disembodied “not being here”, to actual physical collapse. This extreme depression of our normal responses to environmental and social cues serves to trick the attacker into thinking that we are already dead, so no point in trying to kill us. Generally, not a useful response in situations of social conflict and negotiation.

If you think that this must be a rare occurrence, think again. Most of us live stressful lives where our mental and emotional reserves are often on the verge of depletion. In this situation, the level of threat that we experience from relatively minor conflicts and other threats can be enormously magnified.
Most of us, at one time or another, have experienced a feeling of complete deflation and a desire to crawl under the covers for days after a nasty remark from a powerful or important person in our lives. At other times, in a conflict situation, we may experience a feeling of complete intellectual and emotional shutdown; not knowing what to say or how to respond to something while in hindsight you know exactly what you should have said or done!
In short: when we are in a situation of prolonged conflict with seemingly no way out, we are at higher risk of dorsal vagus reactivity, and therefore despondent behavior and intellectual shutdown.
Consequently, when we look at conflict from the perspective of the sympathetic nervous system on the one hand and the para-sympathetic on the other, we want to cultivate the ability to stay in -or otherwise return as soon as possible to- a balanced performance between these two branches of the autonomic nervous system. What does this look like? We want to have enough arousal and energy coming from the SNS to be able to energetically make our point, but also enough calm, intellectual and emotional openness, through an optimally activated PNS, to effectively engage with others in a process of emotional give and take.
It is important to realize that your conflict partner(s) deal with the same processes and what’s more: they can feel where you are in your process, if they have learned to be aware of their own and other’s physical expressions of sympathetic and para-sympathetic arousal.
Shortcuts to Rebalancing the Autonomic Nervous System

So, what can we do to balance our sympathetic and parasympathetic arousal? While we are unlikely to fully control these autonomic responses, there are a few techniques available to us that can dampen high states of arousal. The most practical and useful techniques that I use are a combination of a certain breathing pattern and a focus on specific physical sensations. Granted, these are not techniques that will be available to you without a significant amount of practice, but they are well worth the effort.
The breathing technique is to inhale deeply, and very slowly release, taking at least twice as long for your out-breath as you did for your in-breath. This technique will decrease your heart rate and increase the oxygen supply to you brain.
Focusing on specific physical sensations involves choosing an area of your body, such as your legs, buttocks, hands or shoulders that you monitor for increased tension with the intent to keep those body parts as tension free as possible. This technique will allow you to notice when the tension is rising and relax before the stress levels get so high that you cannot influence it anymore. Do not focus on anything that you can’t actively relax, such as your heart trying to explode out of your chest, or your churning guts or your splitting headache. Using these techniques will also allow you to decrease the threat of tunnel-vision that we referenced in our discussion of the sympathetic response, thereby regaining our ability to think creatively about solutions to our conflict.
Good luck with you practice!