Humans generally think of themselves as highly evolved creatures, but when it comes to stress, our fear response is as primitive as the tiny beasts that fled predators 500 million years ago. Though lifesaving, this fight-or-flight system is also triggered by modern concerns such as political Facebook posts or being stuck in traffic. Over time, psychological stress can build into an internal time bomb.

While some suggest humans have outgrown their stress system, studies show there are ways to teach that old brain new tricks, helping to calm the angst that comes with contemporary living.

Ryan McLaughlin, assistant professor in the Department of Integrative Physiology and Neuroscience at Washington State University, studies the impact of pervasive, day-to-day stress and how it contributes to a rising prevalence of anxiety disorders.

Ryan McLaughlin
Ryan McLaughlin (Courtesy Researchgate)

Referring to Robert Sapolsky’s entertaining book, Why Zebras Don’t Get Ulcers, McLaughlin says, “Our stress system has been passed down nearly intact for eons—we have the same machinery to respond to imminent danger as a zebra does. Birds, reptiles, fish, the lowest level of vertebrates—all have a similar cascade of events to produce the fight or flight response. But today’s stressors are different than those our stress system was originally designed to handle.

“Now, life moves fast. With phones in our pockets, our contacts, colleagues, jobs, and responsibilities are with us every moment,” says McLaughlin. “With more connectedness comes less time to take a break from the trials and tribulations of everyday life.”

Add family problems, financial woes, or an accident, and it can trigger a downward spiral that’s tied to physical problems such as diabetes, high blood pressure, digestive disorders, suppressed immunity, and impaired brain function.

Behind the scenes, several brain centers interact to regulate these reactions to stress. Two of the key players are the amygdala and prefrontal cortex (PFC).

The amygdala is involved in the creation and memory of emotions, notably fear. The PFC coordinates complex behavior, impulse control, and emotional reactions. In a healthy system, the two balance each other like yin and yang.

McLaughlin says trouble comes when the wary amygdala is bombarded by present-day concerns and responds with alerts like, “You’ll die if you don’t get more money or fix a relationship!” He says it’s the PFC’s job to calm the amygdala down—telling us, “You’re not going to lose your job or your wife. Take a breath and make an appropriate decision.”

But if stress continues, the brain begins to change. As we focus on negative concerns, we strengthen those neural connections, setting up an endless cycle of rumination. The amygdala responds by expanding and adding connections to other brain cells, all while sending out warnings that create even more anxiety.

At the same time, the PFC shrinks, losing connections and its ability to control the amygdala. As a result, it gets harder to control your emotions.

McLaughlin says you’re essentially reverting to the childlike state when you couldn’t regulate your emotional brain centers. You find yourself feeling irritable, angry, tearful, overwhelmed, and unable to cope.

Some scientists suspect the amygdala can even become “stuck” in a hyperfunctional state—such as PTSD where the primitive fear center tries to keep you alive at all costs despite the side effects. Researchers in Europe have also linked hyperfunction to chronic illnesses like chemical sensitivity, chronic fatigue syndrome, and fibromyalgia.

Thankfully, most stress-induced brain changes are reversible once you intervene and break the negative cycle.

“It takes some time to recover from a bout of intense stress—about a month or so,” says McLaughlin. “That’s why we need vacations to be a few weeks. We need that time to really revitalize our brain, re-engage the PFC, and get a different perspective.”

Mindfulness training is one way to engage the PFC and quiet the amygdala. In fact, McLaughlin says any sort of novelty, social interaction, or change of routine can help reset the brain and give you a fresh outlook.


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