Did you know that chronic stress can harm your relationships? It’s true. Studies have shown that when stressed, you are more likely to be anxious, depressed, irritable, stubborn, pessimistic, and have a hard time communicating effectively. But there is hope. Changing how you breathe can reduce the negative impact of stress, and help you interact with others with ease. Here’s what you need to know.
The Autonomic Nervous System
The autonomic nervous system (ANS) is responsible for your body’s involuntary functions, like keeping your heart beating, digesting food, and making sure that you inhale and exhale when you need to. It is also a key player in the fight or flight response. The ANS responds to environmental demands by either mobilizing your mind, body, and brain in response to threats, or by calming your system down to allow your body to rest, repair, and grow.
The ANS is divided into two major branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The SNS is like your body’s gas pedal. When you perceive a threat, the SNS triggers the fight or flight response by dumping stress hormones into your bloodstream that increase heart rate, blood pressure, and respiration, contract muscle, and all but stop non-essential functions like digestion.
Stress and SNS activation also activate the fear circuitry in your brain’s limbic system. When this system is active, the prefrontal cortex and other cortical regions of the brain responsible for planning, reasoning, and effective communication are severely inhibited. This makes you more likely to resort to primitive survival strategies like aggression, avoidance, or withdrawal. This is why you may find yourself snapping at others or avoiding them altogether when you feel stressed.
The other branch of the autonomic nervous system, the parasympathetic nervous system (PNS), is the body’s brake pedal, or its “rest and digest” mechanism. When your life is running smoothly, the PNS signals the body and brain to slow down your heart and breathing rates, lower your blood pressure, and relax your muscles. When you’re relaxed, your brain’s fear circuitry is no longer mobilized, letting you access a more flexible range of thoughts and behaviors. Essentially, when you’re not stressed, your mind, body, and brain return to a state of balance. Here you are more able to relate to others with ease, rather than react impulsively.
The Vagus Nerve
There is one more key player in the ANS that bears mentioning: the vagus nerve. Charles Darwin first noted the vagus nerve and its role in social behavior in 1872. In his book The Expression of Emotions in Man and Animals, Darwin proposed that the central nervous system and the vagus nerve engage in a dynamic, reciprocal exchange of information that influences the spontaneous expression of emotion. In other words, the functioning of your vagus nerve directly impacts your behavior.
The word vagus is Latin for wanderer, and the vagus nerve certainly fits the bill. It originates in the medulla oblongata in the brain stem, and projects to most of the body’s major organs, including the heart, lungs, and digestive tract, independently of the spinal column. This complex system of nerve branches relays signals from the brain to the body (efferent), and from the organs to the brain (afferent). This bi-directional communication is what allows your body to efficiently regulate metabolic output in response to environmental demands.
Activity of the vagus nerve is referred to as vagal tone, and measured by assessing respiratory sinus arrhythmia (RSA). RSA refers to the rhythmic increase and decrease in heart rate that occurs synchronously with inhalation and exhalation. When you inhale, your heart rate accelerates, and SNS activation increases, which decreases vagus nerve (or PNS) influence. Conversely, when you exhale, your heart rate decreases, which stimulates the vagus nerve and PNS. The amplitude of the variability of your RSA shows to what extent your vagus nerve influences your heart. Research shows that individuals with greater variability in RSA are more resilient to stress and less prone to depression, anxiety, and substance abuse.
In his influential book The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication and Self-Regulation, Stephen Porges, Ph.D., examined the phylogenic evolution of the human nervous system, and the role of the vagus nerve in the development of social behavior. In his decades of research, he found that the more recently evolved, myelinated branches of the vagus nerve found in mammals play a distinct role in attention, self-regulation, communication, emotional expression, resilience to stress, and other capacities central to social functioning.
These myelinated vagus fibers, which send signals to the brain more quickly than the phylogenically older, unmyelinated fibers, inhibit these older systems. As a result, the newer, myelinated vagal system in mammals can override the signals of the SNS, a phenomenon that Porges refers to as the vagal brake.
The Vagal Brake and Social Behavior
The vagal brake’s primary function is to regulate heart rate through the rapid inhibition and disinhibition of vagal signals to the heart. According to Porges, when the brake is applied, vagal tone increases and cardiac output is reduced promoting relaxation, self-soothing, growth, and repair. On the other hand, when the brake is released, the SNS becomes dominant, and heart rate increases to catalyze bodily systems in response to environmental demands. When this brake is impaired for any reason, phylogenically older autonomic responses are activated, resulting in a narrowed repertoire of behaviors.
According to proponents of polyvagal theory, the vagal brake plays a pivotal role in the development of appropriate social behavior. Because of its capacity to rapidly depress or recruit the SNS in response to environmental demands, the brake gives us the opportunity to willfully regulate our behavior during stressful circumstances.
Numerous studies with infants and young children show that vagal tone is an important indicator of self-regulation, sustained attention, resiliency, and the ability to calm down after experiencing a stressor. This capacity to regulate behaviors is a critically important function in relationship. Those who are able to think and act flexibly, maintain attentional control, and regulate emotions and behaviors are far more able to respond appropriately to interpersonal stressors and demands than those who cannot.
Here’s the catch. This system only works properly when stress is intermittent. When real or perceived stress is chronic, the SNS “gas pedal” gets stuck, making it more difficult for the vagal brake to be applied.
How does this relate to social behavior? In addition to its role within the PNS, the vagus nerve controls the movement of muscles associated with facial expression, speaking, swallowing, sucking, and, most importantly, breathing. As such, your ability to regulate the vagal brake is directly tied to your ability to regulate your emotions, behaviors, and facial expressions—all essential ingredients for good communication.
Vagal Tone and Intentional Breathing
In addition to its impact on facial muscles, the vagus nerve both controls and is influenced by how you breathe. Here is the key: By slowing down your respiration through deep, intentional breathing and elongating your exhalation, you can activate the vagal brake and begin the process of relaxation almost immediately. What’s more, with the resumption of the relaxation response, brain networks in the prefrontal cortex inhibit your fear circuitry, allowing you to regain your composure and relate mindfully to others.
With time and practice, intentional breathing can be used as a powerful tool to defuse stress and manage daily hassles and challenging interactions. Even better, it takes no special equipment, training, or cost to breathe mindfully, you can begin right now, and you can use it anywhere.
Many of my clients and students report that intentional breathing has been key to regaining their presence of mind and improving the quality of their relationships. As someone who has been practicing intentional breathing for more than a decade, I can’t say enough about how helpful it can be, particularly during challenging interactions at home or work, or when your stress level is off the charts. Give it a try!