158 - David Almeida: Can Stress Be Good For You?

0:00Welcome back to the Stanford Psychology Podcast. My name is Jane, and I am a PhD student at the Stanford Psychology Department. Today, I am excited to share my debut episode as a co-host on this podcast, where I had the pleasure of chatting with Dr. David Almeida, a professor of human development and family studies at Penn State University. Dr. Almeida is the principal investigator of the National Study of Daily Experiences, the largest longitudinal diary study of daily experiences and health in the United States, which has surveyed over 3 ,500 individuals over 20 years, encompassing over 42 ,000 daily assessments and counting.

0:42Dr. Almeida's work examines how daily experiences of stress are associated with health and well-being. On the podcast today, we talk about how people experience and react to stress in their daily lives, who is more likely to experience and react to daily stress, the implications of daily stress on health and well-being, tips for managing stress, and even some unexpected upsides of experiencing stress in daily life. So without further ado, here is our conversation.

1:35Hello and welcome, Dr. David Almeida. Today, I am excited to talk to you about your work on the National Study of Daily Experiences from the Midlife in the United States Study. Could you start by telling us a bit about this project, why you were interested in it, and what the central aims were? Sure. First of all, thanks for inviting me to be on the podcast. It's an honor for me to be part of this effort. Like you mentioned, I've been directing the National Study of Daily Experiences now for three decades. The main goal of the project is to characterize the daily lives of adults as they traverse through adulthood.

2:14I would say the thing that distinguishes my work from a lot of psychological work is that my unit of analysis is the day. So rather than trying to understand and characterize a person, what I try to do is just try to understand and characterize a day. And so what we do is daily telephone interviews asking participants about what happened to them in the past 24 hours. So we started the study in around 1995. At that time, doing nightly telephone interviews was seen as the best way to get a daily experiences. Obviously, times have changed, and we charter daily lives through mobile devices all the time, and I can get to that.

2:56But on a general level, we ask participants every night over a series of eight consecutive nights what happened to them in the past 24 hours. So a bunch of structured questions. This includes things about how you spent your time, physical health symptoms that you might have had, your mood, people that you hung out with during the day. a lot of information about your activities, and then some very focused questions about daily stressors that you might have experienced in the past 24 hours. More recently, we've also become interested in good things that happened to you in the past 24 hours. So now we have a list of daily positive experiences that happened to people in the past 24 hours.

3:37And so, like I said, every night we ask our participants to tell us about their day. We do them again around nine years later and go through the same protocol. Then again, 10 years later. As it stands now, the National Study of Daily Experiences is comprised of around 3 ,500 individuals, over 42 ,000 days in the lives of those individuals, and it spans around 20 years. All right, wonderful. Thank you so much. And my first question with that is, why is the day your primary unit of interest? Why not the week, the month, the year, the person level, or within the day? Why not measure every three hours?

4:21What makes the day of particular interest to you? Yeah, I think a day is a really sort of convenient window of information. So oftentimes we live our lives day to day. And so we plan our lives out day to day. We wake up in the morning, think about what we need to do, get to work doing those things. and then we go to bed. And so it's this nice specific unit that has a fairly standard start and a fairly standard end as well. So that's one reason. So the convenience of that time metric is one that's meaningful to me. It's also, there's a rhythm to our days as well. I'm very interested in sort of what goes on throughout the day, but really the day is interesting to me.

5:04I'm also very interested in trying to understand and characterize minor mundane experiences that people have. I'm mainly a stress researcher and a lot of stress research focused on big events that happen in people's lives. So you can think of like a marriage, divorce, starting work, stopping work, a death in the family. All these things are what we would call major life events. And they obviously have a big impact on who we are and who we become, but they don't happen that frequently. So I think that characterizing daily experiences could have an impact just because of their frequency that they happen.

5:41And so a lot of my work has been trying to articulate and understand how these daily experiences not only occur, but their effects on our development. All right, wonderful. I think this is such interesting and important work, because I think if you asked anyone, they would be able to point to a recent stressful activity, though I think also in your work, some people would not be able to, and I'm excited to talk about that more later. But could you start by giving us a working definition of stress? How do you think about it? What does it look like in the body? How does it look like in behavior, in the mind?

6:18Yeah, good question. This is the definition of stress has plagued stress researchers ever since the field started, really, and it continues today. And so I view stress as being comprised of at least, at the very minimum, two components. a stressful event or a stressful occurrence or a trigger or a stressful stimulus, what I call a stressor, and then a stressor response. What is our behavioral, emotional, even biological response to that stimulus? And so for me, in order to accurately characterize and measure stress, I want to have at the very least two components, two dimensions. And so what stress looks like, you could think about the stressor part.

7:06So that could be, I would say, like having an argument with somebody, being stuck in traffic, having a grant deadline. That's a common one for us academics. So that would be the stressor part or caring for somebody. But what a stress response looks like could range from irritation, frustration, anger, sadness. Those are all sort of the emotional components of a stress response. But then there are also behavioral components of a stress response. So when I experience this stressor, I might want to, well, my go-to is probably eat things I don't want to eat. Maybe I don't sleep as much as I need to sleep.

7:46Maybe I don't get as much exercise as I want to do. So there are a whole host of behavioral responses to a stressor. And then there's obviously biological responses to a stressor. We've evolved to have a whole cascade of biological responses to a challenging stimulus. And so these can include rather sort of fast-acting biological responses that are sympathetically activated, things like heart rate, blood pressure. And then there's sort of a more slower response to a stressor. These are the more hypothalamic pituitary adrenal, the HPA responses. And these are things like cortisol. And so it's important to characterize each of these components, but it's also very important to try to understand how they're all working together, not just the responses, but how the stressors are characterized by the response.

8:40And then how those responses can feed back into the likelihood of experiencing a stressor as well. As you were describing this, I thought of a tree falling in the woods as the tree falling being the stressor. and then whether or not someone hears it is the stress response. Like being stuck in traffic, some people might be very stressed out by that, but some people might not be. So it kind of depends on the appraisal of the event. Yes, that's right. So when I said that at the very least, we should have these two components of stress, the stressor and the response. As part of the stressor, I'm of the camp of like you need a stressor, then that will then carry forth some sort of appraisal or meaning making of that stressor.

9:27And so we can all agree that the tree fell, but the extent to which we perceive it as a stressor is part of the appraisal process. And certainly if I was going to add more components to my stressor definition, the next component I would put in there is the appraisal process, which is what is the meaning that we're making of that stressor event. And then as we're talking about stress exposure and stress reactivity, I think one of the amazing things about the National Study of Daily Experiences is that it is a lifespan sample, meaning that it includes people of many different ages from younger adults to older adults.

10:06And I think one of the very interesting findings that your work has is the way stress exposure and reactivity changes with age. You also have the benefit of having cross-sectional and longitudinal data to inform lifespan changes in stress. Could you tell us a bit more about that? Sure. So you brought up some of my two favorite components of the stress process, which is exposure, which is the likelihood or frequency of the stressors happening, as well as the reactivity to it. So once an exposure happens, what's the likelihood or the degree to which you change in terms of your response. The main way that we've looked at this so far is looking at the percentage of days people experience the stressor.

10:51That would be the exposure. So on average, our participants report having a stressor around 40 % of the days. We can look at age patterns in this exposure, the likelihood of a stressor happening. And so what is very clear in our data is that younger people are much more likely to experience the stressor exposure than older people are. So younger people, they report having stressors up to 50 % of the days that we talk to them. Older people are getting down to 20 % of the days. In fact, older men are reporting the fewest amount of stressors. And so that's just the cross-sectional look. When we look longitudinally, we have an age range at baseline 25 to 74 years old.

11:35Now we can track those 25 to 74 year olds over the next 20 years of their life. So now they're going from 45 all the way to 95 years old. And so when we look at change, we see the exact same pattern is that as people grow older, their exposure also decreases over time. We talk about this as being older is associated with lower exposure and getting older is associated with lower exposure. If anything, we see that earlier born cohorts have a bit less exposure than later born cohorts. So 45 year old in 1995 is experiencing a bit lower level of exposure than a 45 year old in 2005. So it's a bit of a cohort difference, but the age pattern is the same.

12:22Now we could switch it to stressor reactivity. And so stressor reactivity isn't just having a stressor, but it is the uptick for us in negative affect on a stressor day compared to a non-stressor day. And so when I say someone is more reactive, basically I'm saying that on those stressor days, their negative affect is increasing a lot more than a non-reactive person. And so I sometimes describe these two people as you have the Velcro person, that's the reactive person on a stressor day. The stressor sticks to them. They get very irritated, frustrated. And at the end of the night, they're reporting high levels of negative affect.

13:02Then you have the Teflon person. Their stressors just slide right off of them. And so even though they have a stressor, they're not frustrated. By the end of the night, they're not reporting higher levels of negative affect. And so what we find here is also an age advantage for stressor reactivity. So younger people have higher levels of reactivity than older people do. And then as you grow older, we see a declining of stressor reactivity up to a point. And so with the exposure, people were declining. With reactivity, we see these declines, but then it flattens out. and it flattens out around age 60.

13:44Or what's happening is that as we continue to collect data, we're beginning to see an uptick in reactivity when people are reaching 75, 80, and maybe even 90 years old. And so in general, I would say that the age pattern shows one of age advantage for dealing with daily stressors, lower exposure, lower reactivity. But for reactivity, this age advantage which doesn't continue throughout the entire adult life course. It kind of flattens out around age 50. Okay. You're saying younger people, such as myself, are exposed to more stress in daily life and are more reactive to it, whereas both older people and as people age, they are exposed to less stress and are less reactive until late in life when you see a slight uptick.

14:35Interesting. That's correct. one way to characterize it is like oftentimes people think there's only bad news when you're thinking about daily stress and i have to say there's one piece of good news with daily stress is that daily stress gets better as you grow older up until point what do you think are the reasons for these age differences that we see yeah so most of the time people think about stresses as an accumulation process so the more stress you have the worse it gets but it was interesting for us, we didn't see this. So obviously, as one girl's older, they basically put more stress in their life course suitcase.

15:09But we're seeing this age advantage. And I would say that the age advantage could be due to two things. One is that, as Laura Carson would say, is that as people are coming to some sort of ending, they're going to maximize the time that they have left. And so it could be that older adults are maximizing time they have left. So they don't have time for stressors. they're exposed to fewer stressors and when they happen, they're not going to be as reactive to them. The other thing that's going on is that one advantage of going through the adult life course is that you learn from your experiences.

15:45And so as I grow older, I learn to know what situations are going to be stressful I can get out of those. Or if the stressful situation does happen, I'm more likely to know how to handle it, resolve it, and move on. And so a good thing about growing older is that you learn how to deal with daily stress better because you've had experience before. Also the social roles that older adults have compared to younger adults. Me, I'm established in my career. I don't have to worry about looking for a job. I'm established in my family role. So I think these larger social roles that you and I inhabit can also be a difference for why we experience different daily stressors.

16:27Yeah, that's a great point. And I think at the very least, a small part of each of those explanations probably rings true and they all come together for a multitude of reasons of why we see these age differences. And in addition to age differences, are there any other individual differences that you see in stress exposure and reactivity? Yes. So first of all, the most consistent individual difference that we see is age. Other important ones are personality. Traits like neuroticism is associated with more exposure as well as reactivity. Conscientiousness is associated with less reactivity. So personality is a big one.

17:06Other sort of sociodemographic predictors, education is kind of an interesting one. People with higher levels of education report more exposure than people with lower levels of education. but people with higher levels of education have lower reactivity. So education protects you in terms of reactivity, but not in terms of your exposure. We've also looked at race-ethnicity differences as well. So people from marginalized racial ethnic groups report both higher exposure as well as reactivity to daily stressors. I would say another really important one. We have looked at how both chronic adversity as well as trauma is associated with daily stress processes.

17:49And just as we would expect, early life adversity as well as current adversity is associated with higher levels of exposure as well as reactivity to daily stressors. That's all very interesting. And the education finding is puzzling. I'd be interested to learn more about that as well to see what you find. And yeah, there could be two, at least two mechanisms going on here. One is that education sometimes brings on more responsibility. And so educated individuals are more likely to have responsibility for more people in their work life. There could be just more facets of your life. Educated people have more time to do volunteer work and things like that.

18:33So that might expose them to more. However, the other thing that could be going on is that we're just not measuring daily stressors' exposures correctly. And that's one that we are working on. Most people who study stress are people who have high levels of education. We came up with these items to measure daily stress, and it could be that we're missing something completely. And so we are beginning to try to find out if there are parts of the daily stress experience that we're just blind to. Yeah, that's a great plug for co-creating research and making sure to include your populations of interest when you're designing samples.

19:12Exactly. All right. And besides aging being one of the things that occurs within a person's life where you see changes in stress processes, when you're looking at longitudinal data, do you see any other changes? And I don't know how many other measures you collect, but for example, do you see maybe someone is experiencing a lot of stress and then you follow up with them and they report a divorce and then they're reporting less stress? Or are there any individual changes? Because you said personality is a big indicator and that is relatively stable. So are there anything, any changes within people that you see?

19:53Yeah. So I should mention that the National Study of Daily Experiences is part of a larger data collection effort called the Midlife in the United States Study or Midas. And so I've been super fortunate to be able to not only collaborate with a whole host of investigators who are interested in other things outside of daily stress. And so we can combine that, but also have access to really amazing data. So everyone who's part of my study has done a whole host of other types of data collection efforts. So I would say the thing that we've looked at most in terms of changes that are happening is the transition to retirement.

20:28And so it's another reason why we would probably see decreases in exposure to stressors It's just that older people are more likely to not be in the paid labor market. And that just basically takes them away from opportunity for those daily stressors. Another big one is when children leave the household, having children in the household is also increased opportunity for daily stressors. And so when children leave the household, that's when we see also a decrease in daily stressors. So yeah, I think it's always good whenever you see an age difference to try to figure out what's carrying that. age is sort of this empty vessel that is composed of a lot of things.

21:04And it could be motivational things like I talked about before, but it also could be these structural changes that are happening as people go through the life course. That's a great point. And my last question before we move on is, what in your data have you found are the health implications for heightened stress exposure and or heightened stress reactivity? Yeah, great question. We've been spending a lot of time trying to suss this out. Early on, we were only interested in the daily health implications. On days you have stressors and stress reactivity, are you less likely to sleep as well? Are you having more physical health symptoms?

21:44Are your levels of cortisol higher on those days? But they're all at the daily level. And I was always so excited about to promote the daily health effects. But I found that other people weren't that interested. It's like, so what? It's just one day. So we started looking at how daily stress is associated with long-term health implications. And so our first paper showed how it's always stressor reactivity that is the driver. The stressor exposure rarely predicts long-term health outcomes. High reactivity is associated with more chronic health conditions 10 years later. And this is even after controlling for current chronic health conditions.

22:24It's also associated with functional health limitations 10 years later. So big general markers of health and well-being. But because we have MIDAS, we can also look at biological markers of physical health. And so we've been able to show how stress reactivity is associated with markers of inflammation. And not only like blood-based markers of sort of cytokines, but also the gene expression of proteins that are associated with inflammation. And then we've also connected daily stress reactivity to cognitive health over time. So people who have higher levels of reactivity are more likely to decrease greater in terms of their cognitive performance over time.

23:07Then the final one that I'll mention is that we've shown how daily stress reactivity is associated with increased risk of mortality over time. And so it looks like higher levels of stress reactivity are associated with these negative health outcomes. And that's where our research has been for, I would say, the past 10 to 15 years. But we have a little surprise now is that we're actually showing that we probably have the wrong assumptions about how stress is working. And so the idea was that daily stress is bad, and daily stress is unhealthy. And certainly, certain types of daily stress are bad and unhealthy, but more and more, we're beginning to see that there's an upside of daily stress as well.

23:53Yes, you transitioned into the next point that I was so excited to talk about so smoothly. That was amazing. Some of your research does indeed focus on people who report no stress in their daily life. Can you tell us a bit about these people and how they compare to the people that do report stress in terms of other characteristics? Yes. So this came about when we were looking at the data, when we do data analysis, because we're so interested in stressor reactivity. The only way to calculate that reactivity is if you report some exposure. And what we noticed was that in our analyses, we were dropping around 10 % of our sample anytime we did these reactivity analyses.

24:36And that 10 % is because around 10 % of our sample never reported having a stressor. And so at first I was thinking that I was wasting my participants' time. They had been part of my study for 20 years, and yet they really weren't contributing to the analyses that we were doing, yet they were contributing their time and effort to the study. And so I kind of wanted to give them a voice. Who are these people? They've never been in my papers. I want to see who they are. And so that sort of started a whole series of analyses looking at the people who report not having stressors, at least not having stressors across the study period.

25:14And so who are these people, these lucky folks that never report having a stressor? And if my assumptions are correct, that stress is bad, stress should be avoided, then these people should be my healthiest people. They never have stress in their life. And on certain outcomes, we did see this. They tend to report higher levels of hedonic well-being. They reported higher levels of happiness. But on other indicators, it didn't look that way. These people were less likely to report having positive events in their lives. They were also more likely to watch television than the stressor group. They had fewer social support exchanges in their lives.

25:53So the people who never experienced stressors also never reported getting or giving emotional support. So then we looked at how are they doing cognitively? and this is what really sparked our attention. People who reported having no stressors in their lives were performing worse on these cognitive tests than people who had at least some stressors in their lives. So then that made us rethink how we were construing stress in general. Like, stress isn't always this bad thing if we see that these stress-free people aren't doing great across the board. Do you think there's maybe something else about these individuals that they're less able to perceive stress or to notice it in themselves?

26:40Yes, absolutely. Great question. I think one of the best things you could do as a scientist and as a researcher is acknowledge limitations that you have in your study. Because I rely on people to report stressors, it could be that we have under-reporters of stressors. And when we look at the sociodemographic characteristics of the stress-free people, they're more likely to be older men. and it could be that these older men are less likely to have stressors, but they also could be just more stoic and not want to admit that they're having stressors. So it's a problem with this type of research. It could be that if I take this finding with cognition, it could be that people who aren't performing well cognitively cannot remember stressors in their lives.

27:26And so that could be an issue that's happening. So I acknowledge that could be a role. One thing that we did that I'm super excited about is that if, you know, there's something that could be beneficial about having some stress, let's go back and take a look at those people who are experiencing stressors. And so we have now begun to reframe our stressor reactivity findings. And so rather than assuming a linear effect of no reactivity is the best, high reactivity is the worst. If there's some benefit of stress, it could not just be on the exposure side, but also the reactivity side. And so we're looking at quadratic effect or nonlinear effects, basically comparing people who have a little bit of stress or reactivity versus people who have no reactivity versus people who have a lot of reactivity.