What a Physician and Resilience and Healthcare Innovator Shares About Nervous System Regulation
By Lienna Wilson, PsyD | Vagus Vitality
Regulation Is Not the Absence of Stress
Eva Selhub, MD, has spent nearly three decades studying how stress physiology, neuroscience, and relationships shape human health and performance. As a physician, an executive advisor, and a resilience expert, her perspective is a useful counterweight to some of the more reductive claims circulating about the vagus nerve. For Dr. Selhub, regulation is never about one nerve or one hack, but about the flexibility of an entire interconnected system.
“To me, nervous-system regulation is the capacity to move flexibly among different physiological states in response to what life requires, and then recover when the challenge has passed,” Dr. Selhub says. “It does not mean remaining calm all the time. We need activation to focus, perform, protect ourselves, and take action. Regulation allows us to mobilize without becoming stuck in overdrive, and to rest without collapsing or shutting down.”
She also describes the nervous system as fundamentally trainable. “The nervous system is adaptive and trainable,” she explains. “Through repeated practices and experiences, we can expand our capacity to tolerate stress, recover more efficiently, and regain access to clear thinking, connection, and choice. The vagus nerve is an important part of that process, but regulation reflects the coordination of the entire system, not one nerve or pathway.”
Leading Under Pressure
Dr. Selhub is direct about what sustained pressure does to the brain. “Under sustained pressure, the brain and body begin organizing around perceived threat,” she says. “Attention narrows, ambiguity becomes harder to tolerate, and people are more likely to react defensively or make decisions from urgency rather than discernment.”
The vagus nerve has a role here too, but she is careful to keep it in proportion. “The vagus nerve contributes to the body's ability to regulate arousal and recover after stress, but it is part of a much larger network involving the brain, autonomic nervous system, endocrine system, immune system, and cardiovascular system. Effective leadership depends on the flexibility of that entire system.”
Her definition of strong leadership pushes back on a common assumption. “The strongest leaders are not necessarily less activated by pressure,” she says. “They are able to remain engaged without becoming overtaken by the activation, and to return to equilibrium once the immediate demand has passed. That flexibility preserves access to perspective, empathy, creativity, and sound judgment.”
The Gut, the Brain, and Leadership Capacity
“The gut and brain are in constant two-way communication through neural, hormonal, immune, and metabolic pathways,” Dr. Selhub explains. “The vagus nerve is one important route, but it is not the only one. Stress can alter digestion, intestinal motility, microbial activity, and immune signaling, while disturbances in the gut may, in turn, influence mood, energy, cognition, and stress reactivity.” That two-way traffic between gut and brain, running through neural, hormonal, and immune channels, is well documented in the broader research literature (Cryan et al., 2019).
For someone in a leadership role, she says that can look ordinary on the surface. “For a leader, this can appear as brain fog, irritability, fatigue, reduced concentration, or a shorter emotional fuse.” But she is careful not to overreach with the connection. “I would not suggest that every leadership difficulty begins in the gut, but we cannot meaningfully separate physical health from cognitive and emotional performance. Leadership capacity is embodied.”
What The Love Response® Describes
Dr. Selhub developed The Love Response® to describe “a physiological and psychological state in which the system is no longer organized primarily around protection and survival.” “In that state, we have greater access to connection, trust, curiosity, flexibility, compassion, and healing,” she adds.
She is explicit that this is not simply another name for vagal activation. “It is related to vagal regulation, but it is not simply another name for vagal activation or relaxation,” she says. “Love can be quiet and soothing, but it can also be energizing, courageous, and deeply engaged. The Love Response® reflects an integrated shift across the brain and body, involving autonomic regulation as well as neuroendocrine, immune, emotional, cognitive, and relational processes.”
Her closing point on this is one she returns to throughout the interview. “The vagus nerve helps support our capacity for regulation and social engagement, but love cannot be reduced to a single nerve, hormone, or physiological pathway.” In one study, increases in perceived positive social connections helped account for the relationship between positive emotions and vagal tone over time (Kok et al., 2013).
The Slow Slide Toward Burnout
“Burnout is often described as exhaustion, but the process usually begins much earlier,” Dr. Selhub says. “When demands repeatedly exceed the opportunity or capacity for recovery, the body adapts by remaining mobilized. Stress hormones, autonomic activity, sleep, immune function, metabolism, attention, and emotional regulation can all begin to shift.”
The early signs, she notes, are easy to miss. “The early signs may be subtle: disrupted sleep, persistent tension, irritability, reduced concentration, emotional detachment, digestive changes, or feeling tired but unable to settle. Because people can remain highly functional for quite some time, they often override these signals.”
What follows, in her account, is a gradual loss of flexibility rather than a single breaking point. “Eventually, the system becomes less flexible. It becomes harder to mobilize effectively and harder to recover. Burnout is therefore not simply the result of working hard; it reflects a prolonged mismatch among demands, resources, meaning, agency, and recovery.”
A Practice for People Who Insist They Cannot Slow Down
“I would not begin by telling them to slow down,” Dr. Selhub says of people who feel they cannot ease up. “I would ask them to build brief moments of regulation into the life they already have.”
Her go-to version is simple enough to fit between tasks. “One accessible practice is to pause between activities and take several slow breaths, allowing the exhalation to be slightly longer than the inhalation without straining. At the same time, notice the support of the chair or floor, soften unnecessary muscular tension, and orient to something in the environment that feels pleasant or steady.” Slow-paced breathing is central to heart-rate-variability biofeedback and can influence vagally mediated cardiovascular regulation, although its effects depend on breathing rate and individual physiology—not simply on making the exhalation longer (Lehrer & Gevirtz, 2014).
She is careful not to oversell it. “The point is not that one breathing exercise will undo chronic stress,” she says. “It is that repeated moments of recovery teach the system that it does not have to carry the activation from one experience directly into the next. Over time, those small transitions can increase awareness, interrupt accumulated tension, and strengthen the capacity to shift states.”
Redefining Resilience
Asked about the biggest misconception in her field, Dr. Selhub does not hesitate. “The greatest misconception is that resilience means enduring more without being affected,” she says. “Resilience is not stoicism, relentless productivity, or the absence of stress. It is the capacity to adapt to challenge, recover, learn, and remain connected to oneself and others.”
She distinguishes a resilient response from an unaffected one. “A resilient person may feel stress intensely,” she says. “The difference is that the stress response does not have to become the person's permanent operating state.”
And she is unwilling to let the framing rest entirely on the individual. “Resilience involves physiological flexibility, but it is also shaped by meaning, relationships, agency, resources, and environment. We cannot place the entire responsibility for resilience on an individual nervous system while ignoring the conditions in which that person is being asked to function.”
Eva Selhub, MD, is a physician, healthcare innovator, executive advisor, bestselling author, and creator of The Love Response®. She is Chief of Medical Affairs at ForHumanity and formerly served as Medical Director and Senior Scientist at the Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital and as an Instructor in Medicine at Harvard Medical School.
For nearly three decades, Dr. Selhub has explored how stress physiology, neuroscience, relationships, and contemplative wisdom influence health, resilience, leadership, and human flourishing. She is the author of six books, including The Love Response, Your Health Destiny, Resilience For Dummies, and Burnout For Dummies, and co-author of Your Brain on Nature. Her work helps individuals and organizations understand the patterns that keep the body organized around survival—and develop the capacity for greater coherence, connection, adaptability, and well-being.
References
Cryan, J. F., O'Riordan, K. J., Cowan, C. S. M., Sandhu, K. V., Bastiaanssen, T. F. S., Boehme, M., ... & Dinan, T. G. (2019). The microbiota-gut-brain axis. Physiological Reviews, 99(4), 1877–2013. https://doi.org/10.1152/physrev.00018.2018
Kok, B. E., Coffey, K. A., Cohn, M. A., Catalino, L. I., Vacharkulksemsuk, T., Algoe, S. B., Brantley, M., & Fredrickson, B. L. (2013). How positive emotions build physical health: Perceived positive social connections account for the upward spiral between positive emotions and vagal tone. Psychological Science, 24(7), 1123–1132. https://doi.org/10.1177/0956797612470827
Lehrer, P. M., & Gevirtz, R. (2014). Heart rate variability biofeedback: How and why does it work? Frontiers in Psychology, 5, 756. https://doi.org/10.3389/fpsyg.2014.00756