By the time she was just eight years old, Sharon Bergquist had already lived a lifetime of stress and trauma.

(Chanting in the protests)

She was a young child growing up during the Iranian Revolution.

There was genuine fury here. Thousands of Iranians, most of them young, rampaged through the streets of Tehran, shouting "Down with the Shah, Death to the Shah."

In 1979, really beginning 1978, the rapid pace at which the country went from a very peaceful situation to just utter, just turmoil.

7000 have been killed. Emotions over the dead and the rumors of dead are high.

Protests in the streets. Food being rationed. It really became very evident that we were not safe. So we left everything and fled as quickly as anybody could get out of a country. I vividly remember being at the airport, we were the last plane to leave before Khomeini came. The airport was incredibly packed. I remember the whole process of trying to get through security and just the mass of people that were there, and how we got onto the runway, every step of it. The plane stopped in Kuwait. Because we are Jewish, they threatened to kill my father. It was a layover because they were trying to take as many people out of Iran as possible and then take us to our final destination, which was England. The airlines had to intercede on our behalf. So to save my father's life. And at every juncture, they separate men from women and children and threatened to kill the men.

Now, that type of stress, I think, for so many of us, is just unimaginable. But thankfully, Sharon and her family did make it safely to their final destination and eventually settled in Atlanta, Georgia. But even then, Sharon faced and overcame a new series of setbacks.

In eighth grade, I could not write a paragraph in English without a lot of struggle, it would take me all night. I graduated valedictorian.

Wow.

But what is really amazing to me, and the reason I wanted to sit down with Sharon, is how she reflects on all of this today.

I view it as a gift to have encountered that in early life, because it puts so much in perspective later in life of what is considered a quote, bad day.

Sharon says it was those early experiences in childhood, combined with the support of her parents, that made her more resilient. She went on to attend Harvard Medical School, and today she's a stress researcher and a practicing physician who continuously uses what she learned to now help her patients.

And what I've learned from it is something that can help other people because ultimately it triggered this obsession for me, of why is it that some people grow and thrive from these experiences and others don't? And the amazing part of it, is that what we need to become resilient is in all of us. Like, there's nothing special about me or my family. We all have this gift in our DNA to become resilient in the face of stress. Most people just don't know how to summon that ability.

She's got a new book called "The Stress Paradox", and in it, Dr. Bergquist goes so far as to say that certain types of stress can help us, help us prevent disease, help us even with aging.

Yes, too much stress harms us, but not enough is actually just as harmful.

Look, it's a bold claim and flips a lot of what we've known about stress right on its head. So today I'm going to ask Dr. Bergquist to make the case for why stress can be a good thing. I'm Dr. Sanjay Gupta, CNN's Chief Medical Correspondent, and this is Chasing Life.

Just going back to childhood for a second, how much of your career then your focus on stress, you're writing a book about stress does go back to what you experienced as a child?

I think the seeds of it were there. I think in retrospect, when I connect the dots, I think that influence is huge. I don't think I made that realization until in my professional career, I became really interested in this question of is all stress harmful? Because I work with a lot of professionals that are very driven, but are also so passionate about what they do, and I would put myself in that category, and so I could not help but wonder, is that a bad thing or is that a good thing?

That's a good question, because as you're saying that, I'm thinking that kind of describes me.

Right.

I live a pretty high stress life, but I'm generally pretty engaged, energetic and happy.

Yeah.

But I would describe myself as stressed.

I would, now knowing what I know, call that good stress. Which I think has a very different effect on our bodies than the harmful stress that has become almost synonymous with what people describe as stress. So for me, it's led to a complete reframing of our relationship with stress. I think I can now say with a comfortable level that, that type of stress releases a biochemical profile that is actually health promoting. We release, for example, dopamine, serotonin, oxytocin...

In response to stress, you're saying.

In the response to stress. And that biochemical response is so different than the simplistic stress response that we think of,

Cortisol and adrenaline...

Exactly. Our stress response is so much more complicated, and different types of stress trigger a different biochemical response. The stressors that are harmful are generally ones that are not predictable, and they're just unavoidable because there's so much uncertainty that leads to some of the harmful effect that is downstream. And often these stressors are not brief and intermittent. They're much more a chronic, continuous, and those are generally the ones that are harmful. When you look at resilience as this muscle, a lot of childhood events, for example, people have dealt with a lot of different forms of adversity in childhood, and there's a lot of literature on how childhood adversity can lead to long term harm throughout life. But that's your passive resilience. When you choose your stress, you are shapeshifting, an active form of resilience, because resilience is incredibly dynamic, just like building muscle is. So when we take on these good stressors, interestingly enough, the hormones we're talking about here, the dopamine for the reward for doing something meaningful, the serotonin, that joy that comes from accomplishment. The oxytocin from contributing to the greater good. That is the trifecta that mitigates our cortisol level. It literally builds our resilience to stress so we don't have to fear it all.

So at the same time, you have stress, you're also building more resilience. It's like a workout I guess, if you're thinking of it from a muscle metaphor.

Resilience is a muscle. And our ability to shape our resilience and to shape the downstream effect of that passive resilience from those childhood exposures. Is like when we could not have ever imagined. So I think that we all have this ability to choose some stressors, these good stressors, and that helps us handle the types of stressors that are unavoidable. And it's really a shifting from kind of playing defense of always trying to curb the chronic stress, fight, wrangle, draw boundaries around stress to one that is playing offense, right? So we are just going to become stronger so we can handle more stress in the future.

If you don't stress yourself at all that that's bad. I mean, you're not going to get out of bed in the morning. You're not going to study for an exam, things like that. But the idea that there's all these biochemical processes that are happening in your body, that wouldn't be happening if you never challenge yourself at all. I think is is the point that you're making. You need this.

I think it's because we understand stress so much better now. In the last two decades, we have cellular and molecular based technology that is looking at what happens down to a very granular level in our bodies. The stress response we're all familiar with is fight or flight, right? The release of catecholamines, the cortisol. But we have this layer of stress responses in our cells, we actually have seven cellular stress responses. And these stress responses in our cells activate our ability to moderate inflammation. So how we understand stress has changed so much. And the key really is that our stress responses are there to help us. They're there to help us adapt to our world. They've, for our entire human history, been how we have survived and thrived. But the things that help us activate those stress responses have been removed from the fabric of our lives. At no time in human history, until the last hundred years, have we removed the natural stressors that were in our environment that were built in like food scarcity, needing to survive on edible plants, needing to have moments of intense exercise, exposure to extremes of heat and cold, mental challenges that forced you to think beyond the horizon. We have increased our lives in a way that have made our lives very comfortable, and we can get a lot of gratification very instantly. We can have access to food 24/7. The introduction of a lot of these comforts has removed our connection with the natural environment that we live in, and the ultimate need of our physiology to express the genes that activate the cellular stress responses. We are essentially handicapping ourselves because we are not allowing our bodies to do what they are so capable of doing.

It's, it's it's interesting. I think anybody who says, hey, I'm going to read a book about stress, they're probably thinking I'm going to read a book about how to mitigate or reduce my stress. And in some ways, doctor, you're making the argument that go out and find yourself some.

Yeah!

But the right amount of stress. The point is the right amount of stress, maybe even more so than calling it good stress or bad stress, because good or bad are attributes that are very much dependent on how much you're getting.

That is such a critical point. This science of what I'm calling good stress is hormesis, it's the science of good stress from this Greek word, to excite is how hormesis was derived, and it is mild to moderate stress followed by recovery. It is not, what doesn't kill you makes you stronger. I would actually say that that is not good stress. The goal is to do stress with the small s, not capital S, and it's those little incremental exposures that ultimately make us stronger. Cortisol is not a good or bad hormone. Cortisol is just telling our body we need energy. You know, exercise can evoke it or we can evoke it through job situations we don't like, financial hardship. I mean, these chronic stressors that lead to your baseline level of cortisol being elevated, which is a very different scenario. So it's not that our body has a moral code. It can our body is just responding to the inputs. And if we can just change the inputs, we change the output.

Now, I want to jump in for a second and make sure you got that, Dr. Bergquist is saying that when we choose to challenge ourselves with intentional bouts of stress that can help us become more resilient to future stressors that may be outside of our control. And to be clear, although we've been talking mostly about psychological stress, Dr. Bergquist also points out that challenging our bodies can be beneficial as well. Like fasting, for example, or intermittent high intensity exercise, hot or cold therapy like saunas. They can all be ways to harness the power of good stress.

Finding tools that are accessible that awaken our natural defense against chronic disease. And I mean mental and physical chronic disease, anxiety, depression, diabetes, heart disease. To me, the fact that we can all access our body's innate defense mechanisms if we just knew how. And that stress is, interestingly, the most powerful lever for doing this became something that I felt more than just my patients needed to know about.

Coming up after the break, Dr. Bergquist helps us create a life full of good stress.

For me, doc, and I think for our a probably a lot of people, I could experience the same stress on a Tuesday and feel defeated by it, whereas on Wednesday I'm emboldened by it. And I don't always know why that is. It could be that I slept well the night before, I had a good meal, I don't know, but it's the same exact stress. And one day it crushes me and the next day I feel fueled by it. How do I summon? How does anyone summon the resilience when they need it the most?

The recovery is a really big part of this day to day variation. So you hit the nail on the head. It is how much you slept the night before. It is also a combination of what did your body go through that same day, right? If you also exercised that day, you ate fairly healthy. All these variables impact day to day resilience. So how much stress a person can handle is not just different person to person is different for the same person from day to day. So I think we can all just make note of what helps us on the days that we can sail through it. Um, the recovery piece, of course, is critical, but looking at other factors, you know, did exercise play a role? Did the amount of sunlight and how you sync'd your circadian biology make a difference? What was that first meal like? I think we could drill it down. I think most of us don't spend the time, you know, doing that kind of human experiment to figure it out.

But so what do you tell somebody in that situation who comes in who's probably a pretty high stress individual and yet loves, loves what they do? How do you guide them, doctor?

I think the key is strategic recovery because our bodies are designed for brief, intermittent stress. That is how we grow. But our bodies need that period of recovery. So when we go through brief intermittent stress in stress mode, our bodies are getting the signal down to ourselves to become more efficient. We do a lot of repair housekeeping functions. It is in recovery that we actually reconfigure and reshape our bodies in a way that helps us handle future stress better. If you go through a period of stress and you don't allow yourself that recovery, you miss that opportunity to actually grow from that exposure to stress. So the key for people who are driven and high functioning is the stress is okay. Do not fear it. Embrace it, but plan for the recovery. And I think that that is ultimately the blueprint of how we become our strongest self, right? Stress. Recover. Repeat. Stress. Recover. Repeat. Because our bodies work through bioplasticity. And in the brain that's neuroplasticity. And we know that when we are exposed to cortisol in a mild to moderate range for a brief transient time, that tells are synapses to make stronger connections like we bind different receptors in our brain depending on the amount of cortisol. The short term, we bind mineralocorticoid receptors. That sends a signal to grow within the communications between our neurons at a high amount. In the chronic state of stress or a very intense amount of stress, cortisol starts to bind the glucocorticoid receptors, which actually prune those synaptic connections. So you want to straddle this kind of Goldilocks amount of stress followed by recovery. So you are benefiting from the stress. And what's really fascinating is yes, too much stress harms us, but not enough is actually just as harmful.

That's really fascinating. But how do you know when it is too much stress, though?

I think intuitively we know. When it's bad stress, we feel exhausted, depleted. We feel we're on the verge of burnout. We want to escape. When it's good stress for energized, for motivated. We're creative. Like we just feel like it's effortless. I think we just have to tune in to our bodies, and I think we just have that knowing. And I think that that's a really good framework for every type of stress. You know, we've been talking so much about psychological stress. I will extend that to the physical stressors in the foods we eat, the type of movement, I mean, stress in a technical sense is anything that challenges your body. And whether your health habit is health promoting or taking away from your health is ultimately how do you feel afterward?

If you feel like you've you've, you're in a bad stress or call it too much stress for sort of keeping this Goldilocks metaphor that what do you, what do you, you want to make sure that you're going into the stressor as sort of ready as you can be, having slept the night before, eating and all that. But if you're in that situation now where you feel like it's too much stress intuitively, you know, what do you, what do you do in that moment?

I think that is your signal that you need recovery. Like when you reach that point where you feel that, you know, if you picture your cortisol level as the metric, if you just feel that is just so high that you're not even functioning effectively, you need to step away. I mean, it could be a walk outside. It could be connecting.

You know, I read this book, which I really loved. I'm sure you've read it as well. It's my second favorite book next to yours, the the it's called "Why Zebras Don't Get Ulcers", Robert Sapolsky. And the point that Robert makes, I'm sure, and you read in the book is like for zebras, you know, they can be chased and while they're being chased, they're the cortisol levels and all this stress stuff goes way up. And then as soon as they're not being chased, milliseconds later, their stress levels come back down. They're happily grazing, whatever. We humans don't quite have that luxury, in part because of this phone that I'm holding up and just all the various things in our lives, so we don't get a break from it. It's that relentless nature of it. Have you seen that worsening in your own practice?

You know, in primary care, 60 to 90% of visits are stress related.

Really?

Yeah. Across the country, national surveys. And I would echo that that would hold for my practice.

60 to 90% stress related.

Stress related illnesses that may manifest as headaches, irritable bowel. It comes in different forms, but that stress plays a big role in the manifestation.

And has that gotten worse over time?

I think that it ebbs and flows. I do think that we are at a period of heightened stress right now. I think, um, that is clearly a big contributor to a lot of illnesses that we're seeing.

Too much TV, too much politics.

Haha. It is and too much information and very hard to know how to put the information in a larger perspective of whether it's just current state or whether it's just that we now have the awareness about a lot of things that our parents dealt with, but we just didn't have the same level of awareness.

Right.

Right? So, it's the access to that information.

Yeah. I mean, look I say this in part in jest, but also someone who works in the news business, it's a lot. Um, it's a fire hydrant of information and a lot of it's not good. And I think just to be completely immersed in that all the time, even as someone who's in the business from a medical standpoint, you can recognize that that's not good. Finding breaks from that. By the way, are your parents still living?

My mom is. My dad passed away November of 2022. He was a man of very few words, but what he would choose to say always carried a lot of weight because it was always very thoughtful and reflective. And the book truly is dedicated to him. It's in his memory because he had this unbelievable acceptance, stoicism and resilience and handled everything that came his way with unbelievable calm. And I now term that resilience because we know at a biochemical level that people who have that kind of resilience emit an energy that invites calm instead of chaos, that attracts rather than repels, that inspires instead of evokes fear. And my father had that. And for me, this is a way of breaking down, defining and putting terms to what is it about people like that, that become this, you know, people would describe my father as whatever corner of the room he was at, that is where you could find peace and serenity. And people would just gravitate towards him when, you know, people were in a scenario at a party or an event where they needed that sense of calm. And I feel that now I understand what is it about people who have that and the amount of synchrony in their body, in their soul that emits that type of energy. And I think we're all capable of it, and I think that we can get to that point if we are willing to go past our comfort zone, even for brief amounts of time, again followed by recovery, because that is the path of getting there. That is how we create this positive, virtuous cycle in our world. And I hope that everyone makes that investment in themselves, because ultimately it's an investment in other people.

That was Dr. Sharon Bergquist and her book, "The Stress Paradox" it hits bookstores this week. Chasing life is a production of CNN Audio. Our podcast is produced by Eryn Mathewson, Jennifer Lai, Grace Walker, Lori Galaretta, Jesse Remedios, Sofía Sánchez, and Kyra Dahring. Andrea Kane is our medical writer. Our senior producer is Dan Bloom, Amanda Sealey is our showrunner, Dan Dzula is our technical director, the executive producer of CNN Audio is Steve Lickteig. With support from Jamus Andrest, Jon Dianora, Haley Thomas, Alex Manasseri, Robert Mathers, Leni Steinhardt, Nichole Pesaru and Lisa Namerow. Special thanks to Ben Tinker and Nadia Kounang of CNN Health and Katie Hinman.