Strictly speaking, stress doesn’t cause ulcers. A bacterium does. Robert Sapolsky, author of the highly influential book Why Zebras Don’t Get Ulcers, has been clear about that. But his famous phrase was never really about ulcers. It was about something more fundamental: why the human stress response is so easily, and so chronically, activated—long after any real danger has passed, and even in the absence of any danger at all. Unlike zebras, we humans get stressed by the mere thought of future threats—events that haven’t occurred and may never occur. And while the zebra stress response is primarily triggered by real and immediate threats to their physical survival (e.g., a lion or other predator), we humans also get stressed by threats to our psychological well-being—a verbal slight, a conflict with our partner, being ghosted on a dating app, or a humiliation at work. We even get stressed by situations that are simply inconvenient but not actually threatening, like sitting in traffic, waiting in line to get a new driver’s license, or missing a bus.
We have become masters at becoming stressed and remaining stressed for long periods of time. That may sound harmless or merely annoying, but it’s far more serious than that: Chronic stress weakens the immune system, leaving us vulnerable to illness and premature death. It increases the risk of substance abuse and chronic insomnia, impairing everyday functioning. Neurologically, chronic stress is related to the death of neurons in the hippocampus, a brain structure critical to healthy memory. And it has been linked to shortened telomeres, the caps on our chromosomes that protect our DNA. Telomere erosion leaves us vulnerable to a host of age-related diseases. And finally, stress harms our relationships, because when we are perpetually stressed, we are much more likely to lash out in anger and less able to respond to our loved ones with patience and warmth.
Chronic stress is toxic.
A Tiny Primer on the Stress Response System
The human stress response evolved to help us survive short-lived, high-stakes threats. Faced with predators, violent conflict, or natural disasters, our bodies mobilize rapidly and effectively: hormones surge, attention narrows, energy is diverted to the muscles, and the odds of survival improve markedly. When the danger passes and the stress response shuts down within minutes or hours, most people return to baseline functioning with little lasting harm. In fact, research shows that most people exposed to potentially traumatic events do not develop long-term psychological disorders—a reminder that, as a species, we are far more resilient than we often assume.
This is such an important point: We usually recognize potentially traumatic experiences as worthy of our attention and of meriting support, whether from friends and family or from a mental health professional. But we generally downplay the effects of chronic everyday stress until we find ourselves incapacitated by anxiety or depression, or having a panic attack, or in a doctor’s office seeking help for a stress-related illness.
When Protection Becomes the Problem
If acute stress shows us how well our stress response system works, chronic stress reveals where it breaks down. Problems arise not because the stress response is poorly designed, but because it is so easily and repeatedly activated in modern life.
Once a situation is perceived as threatening, brain systems involving the amygdala and prefrontal cortex set off a cascade of physiological changes: adrenaline surges, digestion and growth are put on hold, and the body prepares for fight, flight, or freeze. A second wave of hormones, including cortisol, is then released to help shut the system down and restore balance. This sequence works beautifully when stress is brief and escapable. But when stressors are chronic or inescapable, the system is forced to stay online—and the very processes that once protected us begin to erode our health instead. The problem, then, is not stress itself—but its duration and repetition, and the lack of recovery. This is not a failure of biology. It’s a mismatch between an ancient and highly evolved stress response system and the conditions of contemporary life.
What We Can Do
If chronic stress is an adaptive system stuck in the “on” position, then reducing stress means either helping the system shut down—or removing the conditions that keep it activated.
Problem-focused strategies entail changing the situation that is causing us to feel stressed—that is, altering the stressor itself. This could mean:
- leaving a stressful job
- moving out of a high-stress neighborhood
- getting out of an abusive relationship
- working more frequently from home to avoid a high-traffic commute
Other examples include seeking couples therapy to reduce conflict and strengthen intimacy, or joining a running group to lower the stress of loneliness. Problem-focused approaches to lowering stress are powerful in that they target the source of stress rather than trying to minimize its harmful effects.
Of course, we can’t always change the sources of stress in our lives. Emotion-focused approaches focus on changing how we make sense of and respond to stressful situations rather than altering the stressor itself. Meditation, yoga, dance, and exercise are all excellent, evidence-based ways of dialing down the stress response.
Sometimes, however, the biggest source of stress is our own tendency to interpret situations in ways that leave us feeling highly stressed. This is especially common among people whose self-esteem has been negatively impacted by early life adversity. Mindset approaches focus on changing how we interpret potentially stressful situations—for example, if we tend to feel easily slighted, we might challenge ourselves to consider a broader range of reasons for other people’s behavior. Did that person arrive late because they don’t care about me, or because they’ve had a rough and hectic day? Or if we tend to catastrophize, we might work on changing that—for example, if I miss a bus, is it truly a disaster? Or can I simply take the next bus and apologize for arriving late?
A Cautionary Note
The subtle dangers of prioritizing mindset and other emotion-focused approaches are twofold. First, there can be an unintended but harmful message of personal failure if we still feel highly stressed despite repeated attempts to meditate or change our stress-related mindset. It may simply be that we need more guidance, or a different strategy. For example, over the years I’ve learned from my students and clients that meditation is not for everyone, and have found that there are infinite ways of incorporating stress-reducing mindfulness activities into our lives other than sitting on a cushion in Zen-like stillness. More pernicious is a focus on emotion-based solutions to stressful situations that really can be changed. For example, I’ve been asked to provide stress management training to the stressed-out staff of organizations where the primary causes of their stress were poor management, excessive workload, and a punitive work environment. All the mindfulness training in the world wouldn’t have lowered employee stress in such conditions.
Zebras don’t get ulcers, not because they are calmer, wiser, or better at managing stress, but because their stress response does exactly what it evolved to do: turn on in the face of real threat, and turn off when the danger is past. We humans, in contrast, respond to threats both real and imagined, and contend with a host of ongoing environmental and psychological stressors that can leave us continually stressed. Learning to live well in such conditions requires more than calming our minds. It requires helping our bodies return to a state of calm, and, where possible, changing the conditions that keep our stress response stuck on high alert. The lesson from the zebra is to appreciate the incredible survival value of our stress response system while minimizing its unnecessary or prolonged activation.
