Kelly McGonigal, author, Stanford University psychologist and pioneer in the new field of “science help” – translating academic science into practical use – challenged the conventional view that stress is bad with her viral 2013 TED Talk, “How to Make Stress Your Friend.”

In her new book, The Upside of Stress, McGonigal argues that stress can “transform fear into courage, isolation into connection and suffering into meaning.” She explains:

Q: There are a host of studies showing how stress is bad for our health. Stress has been associated with high-blood pressure, cardiovascular disease, diabetes, inflammation, cancer; newer studies are showing it can shrink the brain. Yet, you argue there’s an upside to stress?

A: It’s not that the research that stress is harmful is all wrong. But, it really needs to be put in context. That science is largely based on animal studies that are largely based on a model of torturing animals – depriving them of social contact, restraining them. They’re designed to create a defeat response. And when stress shrinks the brain, damages the heart, I argue it’s not from the stress itself but from a toxic relationship to stress.

Q: A toxic relationship to stress?

A: When stress feels against your will and out of your control, if it’s completely devoid of meaning and if it isolates you from others, that’s what I mean by having a toxic relationship to stress. And if you have that kind of stress, then it really is associated with the consequences that we fear.

Yet, there is as much or more research that shows stress doesn’t increase the risk of depression or other harmful health outcomes when you have a different relationship to it. It’s how you think about stress that determines how it affects you. And, many times, how we think about stress is the only thing we can control.

Q: What changed your mind about stress?

A: The first real trigger for me was a study published online in 2011 that showed that having a high level of stress only increased people’s risk of mortality when it was combined with belief that stress was bad for health. The same was not true among people who had high levels of stress but didn’t believe it was bad.

That study confused me. It was a real existential crisis for me because my mission as a health psychologist is to help people. I’d been indoctrinated that stress is the enemy, and we need to reduce or avoid stress. ... There’s no hope there. Then, you’re more likely to isolate and withdraw, and practice avoidance coping, like drinking.

That sent me on a journey to find out if that was right. That’s when I found several other studies that show it’s how you think about stress that matters. For instance, the Whitehall study in the U.K. showed that stress increases cardiovascular disease only if you believe stress is harmful.

The other moment that convinced me: I began teaching in my science of stress class how embracing stress can help you handle stress. And the look on my students’ faces – I had never seen before. I began introducing research that shows stress can be helpful in high-pressure situations to enhance performance. And the more you take that mindset, the more stress and anxiety can propel you to greater success. Afterward, people thanked me for the lecture.

But what made me commit to making this switch is not only that the science is good, but in my first book on chronic pain, The Willpower Instinct, my scientific work on compassion, the underlying premise of all of those is the more you try to avoid and resist the suffering, the worse it gets. The more you mindfully accept it, the anxiety, the suffering, the stress and take action anyway, the more it improves your own well-being.

It takes shifting your stress mindset.

Q: How?

A: Think of stress as a signal of meaning, not that you’re inadequate to the challenges in life. Trust your human capacity to transform stress into something good. People who are more stressed out, who worry more, surveys show, are also more likely to say their lives are meaningful.

For instance, last night, I got this email. It made me really sad and disappointed. It took me a few moments, but then I realized, the disappointment and sadness were signs of how much I cared. And once you recognize that, it’s important to stay engaged, and to think about what action you can take that’s consistent with your goals and values.

That is the mindset shift. Instead of seeing stress as a sign that something’s wrong, and then choosing a response that’s more destructive – like thinking, “I’m not cut out to be a parent” or “this job is too much for me” – think, “OK, I’m angry right now. I’m overwhelmed because something I care about is at stake. So what do I want to do about that?”

Maybe you feel like you’re in a bad place and you care about your health, so you decide to practice self care. Or you want to stand up for yourself. Or apologize to someone because the relationship matters.

Even the anxiety that comes with stress – research shows that if you choose to believe that anxiety can help you, that it’s part of your body’s way of trying to give you energy – that can help you meet peak performance challenges.