Dr. Alexandra Crosswell is an Assistant Professor in the Department of Psychiatry and Behavioral Sciences at the University of California, San Francisco. She’s an expert in psychological stress, and has recently completed a leadership role with the National Institute of Health, where she led a large initiative to improve stress measurement across health research. Alexandra’s research focuses on understanding how stress impacts health and well being, and how spiritual practices like yoga and meditation can combat the negative biological effects of toxic stress. (Our conversation has been condensed and edited for clarity.)


What is the definition of stress? And how would you measure stress? 

Many of us know what stress feels like, but might describe it in different ways. As psychologists we say that stress occurs when the demands of the environment outweigh the resources you have to adequately cope with them. For example, let’s take work stress, which is when the demands of the work environment build up so much that you don’t have the resources, the support of colleagues, or the right tools to actually meet those requirements. That’s when the scales get tipped and you report the perception that you’re under a high amount of stress. 

Many people also say you can measure stress with biological indicators like cortisol. But as stress experts, we push back against that, because cortisol actually goes up naturally throughout the day, regardless of whether you’re stressed. Even if you’re on vacation, or at a meditation retreat, cortisol still goes up. So what this means is that there’s no biological indicator that is specific enough to show that you’re under stress. You need both the perception, the feeling of stress, and to know biologically what’s going on, if you want the full picture. 

Do you think that’s why it’s taken us so long to understand the relationships between stress and the onset of disease? 

I think that’s a PR issue! We’ve actually known for over 50 years that stress leads to increased rates of diabetes, cancer, cardiovascular disease, etc. The problem is, there’s no drug that’s going to fix it. So there’s no incentive for medical institutions to go out and really preach about the connection, because there’s no quick fix to address it. 

Getting back to the how, can you describe the effects of stress on our body and on the onset of disease and ageing?

This is a really exciting area of work that over the last 20 years has had very compelling scientific literature outlined in both human and animal models. I work with Dr. Elissa Epel who, along with Dr. Elizabeth Blackburn, discovered that chronic stress accelerates the biological aging that’s occurring in telomeres, which are the caps on the end of a chromosome; stress causes them to fray at a more rapid pace. 

Before this telomere discovery, the most well studied link between stress and our physiology was the autonomic nervous system. The autonomic nervous system has two branches, the sympathetic branch and the parasympathetic branch. The sympathetic nervous system is what is activated when you’re under an acute stressor like when you get in an argument with someone or you are about to ask your boss for a raise. It’s when your system is revving itself up to cope with an intense demand. You start to sweat, your palms get kind of sticky, your heart starts beating and your blood pressure increases. This is a core part of the physiology of stress. It’s the fight or flight response that was designed evolutionarily to help us escape a predator. So back in the day, if we were worried that we were actually in danger, our system would rev up and start pumping blood out to our muscles so we could run away really fast. Now if you’re about to walk into your boss’s office to ask for that raise, your body actually produces that same response, because it thinks that there’s a stressor that’s about to occur and it’s trying to prepare you for that stressor.

Is all stress bad for you? Can you differentiate between good and bad stress?

One of the coolest and most applicable research findings in this area to people in their everyday life, is that a stress response can be good for you. What it does, in addition to pumping blood into your muscles, is it also pumps blood to your brain. And when your brain gets more blood, it gets more oxygen. And when you have more oxygen in your brain, it functions better. So the stress response helps you focus better, perform better, think quicker, and make better decisions in the moment. 

Making sure that the stressor does indeed lead to a positive outcome is very psychological – you have to interpret that stressor as a challenge instead of as a threat to yourself. This is based on research by Dr. Wendy Berry Mendes at UCSF. For instance, when you’re walking into your boss’s office to ask for that raise, you psych yourself up by saying: “This is a great challenge for me.  I’ve built a really great rapport with my boss. I’m coming with a really thoughtful argument for why I deserve this raise and how it’s going to be more in alignment with salaries of comparable colleagues. This will be a great challenge for me.” 

When you have a challenge versus a threat response, your actual physiology is different. When you’re in the challenge response, your body opens up its blood vessels, so more of that blood and oxygen get to your brain. Then you have a threat response, you still have the blood pumping, but it’s constricting so you are limiting the amount of blood and oxygen that’s reaching your brain. 

It’s important to note that you don’t want the sympathetic nervous system response to happen all day every day. When this happens, stress turns toxic. When you’re constantly in a high threat sympathetically-aroused state, your systems get burned out. It’s that system burnout, called allostatic load, which eventually over decades leads to increased risk of cardiovascular disease and cancer.

This is really fascinating. So what you’re saying is, it’s not the stressful event in and of itself that is harmful to our bodies, it’s our perception of the stress and the event?

That’s right. Much of the impact of stress on health is about our own perceptions and response to the stressor. I think it’s important to have a caveat though. I published a study that showed that using the app Headspace every day decreases perceptions of stress and anxiety. But I like to make the argument that while it is true that perceptions of stress and anxiety levels did decrease for the people who used the Headspace app, it doesn’t mean that we can place all the onus on managing stress on each individual person. Most of the stress-relieving changes in a workplace need to happen from the top. If somebody just has too much work, and they don’t have the time, the resources or the tools to get that work done, that has nothing to do with whether they can cope with it or not, it has to do with the institution making changes to balance it out. We have to be careful with blaming the victim and balance that with the fact that a lot of times people are in situations that are really untenable.

What do you think workplaces should be doing to combat the negative effects of stress and make happier and healthier places to work?

I read that there are three things that play into high levels of work stress in corporations. The first is not being verbally acknowledged for the contribution somebody is making. The second is not being financially compensated or rewarded to the point that feels adequate for the amount of effort somebody is putting in. And the third is not having the social support needed to get through the difficult time. Leaders should be thinking about how they utilize one, two, or all three of these levers to decrease work stress and increase employee engagement.

What is your top tip for reducing stress and cultivating wellbeing in the workplace?

Appreciation and acknowledgement. There’s been so much research on the benefits for an individual of cultivating gratitude. I like to take it to the next level and say, how can we make gratitude a tool for greater connection to others? How can you take that gratitude or that sense of appreciation, and give it as a gift to other people so that they can inherit the energy through saying thanks for doing this, you really did a great job on this. Feeling seen and acknowledged for the high level of work that we’re putting in can reduce levels of work stress, and improve overall well-being.


  • Reeva Misra


    Walking on Earth

    Reeva is Founder and CEO of Walking on Earth, a digital wellness platform. She is a certified Jivamukti Yoga Teacher in London and Founder of Vahani Scholarship. She holds a BA in Experimental Psychology from Oxford University and a MA from the Jackson Institute for Global Affairs at Yale University.