Reframing exercise: How simple physical activity boosts health

0:13 [AUDIO LOGO] GRETCHEN REYNOLDS: Hi, and thanks very much for joining us. I'm Gretchen Reynolds, a health columnist for The Washington Post, and I'm today's moderator. Joining me is a really amazing group of speakers from research, clinical, and athletic perspectives. And we're going to do our best to demystify the links between exercise and health. And hopefully we'll also debunk some myths along the way. But first I want to introduce our panelists. We have Brooke Forde. She's an Olympic silver medalist in swimming

0:59 and a project coordinator at the Harvard Chan School. I-Min Lee is an epidemiologist and a leading researcher on physical activity, health, and longevity. Mia Sanchez is a marathoner and a very newly minted graduate at the Harvard Chan School in environmental health. And Meagan Wasfy is a sports cardiologist at Massachusetts General Hospital who studies how exercise influences heart health. So I want to start with a rapid fire question for everyone, which is, why do you exercise? I-Min, do you want to start? I-MIN LEE: Yeah.

1:44 So I'd like to quote Professor Ralph Paffenbarger, the late Professor Ralph Paffenbarger, who was my mentor and one of the pioneers in the field of physical activity and health. He said exercise adds years to your life and life to your years. Full disclosure, I have an additional reason why I exercise. Now, I'm not athletically talented like our other four panelists, so I need a little bit more of a push to get myself to exercise sometimes. And when that happens, I tell myself I have to exercise in order to give legitimacy to the work that I do. I can't just do this research and not do what I tell people to do.

2:31 GRETCHEN REYNOLDS: And Meagan, do you want to-- MEAGAN WASFY: There is some practice of what you preach, I-MIN LEE, that keeps me consistent. But I'll say, I have been more competitive versus others in my youth, and I get the urge to go back to that racing mentality intermittently now in midlife. But mostly, now running, for me, my preferred sport, is more about feeling strong, healthy, and peaceful. And so that's shifted for me over my life. GRETCHEN REYNOLDS: Yeah. Brooke. BROOKE FORDE: Yeah, similar. I mean, for a while, the reason I exercised was because it was my job. My whole focus was achieving new goals through pushing myself physically. But now, even after retiring from competitive sport,

3:18 it's still such a big part of my identity. And as others have said, it's the time when I feel most like myself, most confident and most at peace. GRETCHEN REYNOLDS: And Mia. MIA SANCHEZ: Yeah, similar to what the other panelists have said, especially what Brooke just mentioned about your sport being your job for a long period of time, that's how I felt running competitively in college. And it's just so ingrained in who I am as a person. And now exercise is this outlet for me to spend time outdoors, either by myself or with my friends and family.

4:04 I know GRETCHEN REYNOLDS: For myself, I'll reiterate what I-Min said, which is, I'm an exercise columnist. And so I feel like I have to exercise, although I spend a lot of time writing about exercise and not doing it. But one of the big issues is, do we know why and how exercise actually affects health and why it's so important for our health? Can you start discussing that? I mean, I know it's a big question, but it's also really fundamental to the whole topic of, does exercise affect health? I-MIN LEE: Yeah, so exercise, physical activity,

4:52 we know from a large body of data, that this way of life improves almost every aspect of our lives. So, as I said, it helps us to live longer, in part because it reduces the risk of developing many chronic diseases. Physical activity also helps us to function better, both physically and mentally. It improves our quality of life, in part, because it reduces anxiety and depression and helps us to sleep better. It's also important for weight control, weight maintenance. It builds strong bones and muscles. So I think that's why moving is so important for our health. GRETCHEN REYNOLDS: But do we know at this point how much exercise we actually need?

5:41 I mean, there's a really entrenched myth, that you know very well, that we need at least 10,000 steps a day. Can you talk a little bit about where that myth came from and then what the reality is, not just of steps, but of physical activity, the amount of physical activity that we need? That would be great. I-MIN LEE: So I'm just going to start with a word exercise. We say exercise. And when we say exercise, usually, we mean the kinds of things that you guys do, running, rowing, going to the gym. And this is a little bit daunting to many people

6:27 because they're not exercise people. We've increasingly seen, with a large body of research, that it's not just exercise, but any physical activity that is helpful to health. So to give a little bit of context, in the past, when we did research studies on physical activity, the only way we could assess physical activity-- I shouldn't say the only way, but a major way that we assess physical activity was to ask people about their activity. And, of course, people remember exercise things better than say, washing teacups yesterday or cleaning the house, because that's less regular. You might not report it as well. So our recommendations, currently, the latest recommendations for public health, are from 2018 in the US

7:14 and 2020 in the World Health Organization. They rely on a body of data that largely used self-reports of physical activity. As you all know, over the last period of time, variables are becoming increasingly common, and we've started to collect data on variables in health. So we can use these variables, which don't rely on our memory, but it can. The variables can actually measure physical activity in smaller quantities. And it's very encouraging to see that the dose of physical activity we need for health is actually quite low. Even light intensity physical activity like slow walking, as I said, doing light housework, washing dishes has been shown to be helpful, particularly in older people. And I like the 10,000 steps question that you asked

8:00 because it's very conventional. It's a nice number. It's easy to remember. But if we look at the history of this, the 10,000 number actually originated in the mid 60s in Japan. Japanese were the first people to sell commercial pedometers. And at that time, they sold pedometer which we called the Manpo-kei. Man in Japanese means 10,000. So the manpo was 10,000 step meter. And it's got a nice sound to it. Easy to remember. And Gretchen, as you know, you covered a study that we did some years ago when we wondered, do you really need 10,000 steps? And so we published one of the first studies to ask this question specifically, do you need 10,000 steps to be healthy? And the answer was actually no.

8:47 So what's encouraging is that some is better than fewer. More is better. But at some point, the benefits taper. And it makes sense. You can't live forever. You can't lower your blood pressure to zero. So the tapering of the effect based on steps depends on possibly the population, how old they are, and what outcomes you're looking at. So for example, if you look at cardiovascular disease and cancer, among older people, the benefits probably start to taper around 6,000 to 8,000 steps, which means if you've got 10,000 steps, great for you. But you probably no better off than someone who took 7,000 steps. GRETCHEN REYNOLDS: And Meagan, as a cardiologist, how important is--

9:33 whether we find it as exercise or just physical activity, or not sitting for heart health? And are all of those the same? I-MIN LEE: It's a really great question. I love the way I-Min frame things, as you got exercise, which is like the structure, and you have a goal to it. And then in research, however, you want to think about the broader lens of physical activity, which could include housework or commuting or many other ways we move our body. And now that we have more and more information from accelerometers that are nihilistic, they can't tell whether you're biking to get to work or biking for exercise. The summary is from the heart, but I think also from the whole body. It doesn't know what shoes you have on your feet.

10:20 You can't tell the intention. There's probably subtleties there. When we think of binning it separately as exercise, it may have more of that mental health benefit than physical activity done for getting from one place to another around the home. But from a heart health perspective, that total amount of human movement is what we see strongest relationships with. And really to emphasize the message that any movement adds to health, which should be empowering. The idea that you don't have to get up to 10,000 steps, though, that is a modest goal and many people can achieve it. But even improving from something very low, like 500 or 1,000 steps today, up to several thousand, or if you want to think of it in the terms of minutes from zero minutes up to even a half hour or an hour of movement a week, is better than no movement at all for patients that are really

11:06 exercise or physical activity deficient. And then dosing from there, our guidelines hit a sweet spot. We're aiming for around 150 minutes of moderate intensity physical activity a week. Both has really great health benefits, both to longevity but also specifically heart health, but from a public health perspective, is very achievable and doable for many people. GRETCHEN REYNOLDS: Is it possible, on the other hand, though, to do too much? Is there good evidence about-- is there a plateau that you shouldn't go past? We have our athletes here who would probably know too, but Meagan, do we know if there's a point at which you

11:52 could be doing too much? I-MIN LEE: I'll speak first to the question of a plateau, which a lot of this has been I-Min's work, where if you're looking at a dose response, there is the idea you can't exercise yourself to immortality. You're seeing these massive improvements in longevity and reductions in cardiovascular disease, but you can't reduce those risks to zero with physical activity. It just stands to reason. And those plateaus tend to occur around several multiples of our bare minimum recommended physical activity doses, so around three to five times that bare minimum of 150 minutes of brisk walking a week. Or you get double credit if you're doing anything more intense. So you're not really seeing further health benefits if you go beyond that dose.

12:38 And that's relevant to me in my practice because I see, mostly, athletes who are sometimes orbiting way above that dose. I always like to anchor to them, what's their why, make sure that individuals understand that beyond that given dosing, on average, you're not seeing health benefits. We have to acknowledge we don't actually know, in an individual human, what their personalized, optimal dose of physical activity is. And as I-Min pointed out, it stands to reason, even over your lifespan. That probably changes from a younger person, for example, to an older person. The best studies we've had looking at the tail end of the dose response curve is that responsibly we can't say there's too much physical activity. I-Min's been part of studies where they've aggregated data from over half a million individuals. And yes, you can see mortality goes down, it plateaus,

13:24 and then there's a numerical uptick. But it's very few people that are doing those super high levels of physical activity. And so when you see the uptick, in scientific sense, we're not sure if it's there or not. It's not, statistically, been shown that you can see an uptick in risk as too much exercise. But we do know there is this paradoxical idea, which is that physical activity and exercise, overall, lower our risk of sudden heart events, but that an hour spent in exercise is riskier than an hour spent at rest. And that's obviously stands to reason for people that, unknown to them or maybe known to them, harbor cardiovascular disease risk-producing conditions. So for individuals where there is a condition or a diagnosis, it's really a subtle and personalized discussion

14:10 for them, what's the too little, just right, too much? GRETCHEN REYNOLDS: Well, I'm really interested in the athlete's perspective on this for two reasons. One is, did you, as athletes, ever worry that you were doing too much? And then also, as you've moved from being athletes to being more like the rest of us, how have you transitioned from working out for performance to working out, presumably, for health? What was that process like? So, Brooke, do you want to answer both of those? BROOKE FORDE: Definitely, yeah. These are things I think about all the time.

14:57 I mean, as an athlete, definitely. It was actually quite a fine line in terms of, are you doing enough or versus too much? And it may be not so much from a cardiovascular perspective, but more from a overall mental and physical perspective. I mean, the commonly used term among athletes is burnout or overtraining syndrome, things like that, which I saw in several of my competitors and peers as I was training. And it really is, I think, difficult to know for each person. And it can be different at different times, what actually leads to that, whether it's more cumulative or there's one really hard workout on a given day

15:43 that really just wipes you out. And so it came down to a lot of using intuition, which is hard to develop as an athlete because you're so used to relying on numbers, on feedback, like times, for your performance, and using that to determine how much is enough. And the intuition piece actually is what I've really had to work on as I retired from competitive sport to know, again, as we were talking about, what's too little, just right, too much exercise. And it's hard, I will say, not having a coach telling you exactly what to do and not having a specific set amount of time that you need to exercise and really just having to feel like, when does my body feel the best and the healthiest and what set of exercise movements

16:31 is going to lead to my best version of myself where I need to be at life right now? And I think one of the hard parts of that as well is setting new goals for yourself that are realistic for where you're at. And for me, one of the craziest things that somebody told to me, or most, maybe, revelational things that somebody told to me after I retired from swimming, was that exercise doesn't have to hurt. And really, it changed my whole mindset because as an athlete, really, believed that unless it was really uncomfortable and painful, I wasn't getting better. And to change my mindset to exercise can really just be like a pleasant walk.

17:18 That feels great and that's still good for you and that's enough on some days. GRETCHEN REYNOLDS: And Mia, for your part? MIA SANCHEZ: Yeah, I would say that balance was definitely something that I struggled with, my progression as an athlete to now more of just someone who's enjoying exercise. It's been a journey to find that balance. In college, I was running and training at a very high intensity, and it developed into an obsession with exercise, and it pushed me to the point of getting a stress fracture, which led me to be completely off of exercise

18:05 and immobile for eight weeks. I couldn't walk on my leg at all, and I didn't get to run for three months after that injury. And during that time, it was really hard, but it was a moment when I was able to stop and reflect on my why of exercise and how I could find that balance. And then moving on from college and into graduate school, there wasn't as much time for that high, intense training that I was so used to for so long, but I was able to find that love for not only running, but other forms of exercise. Going outside and playing volleyball or soccer

18:53 with my friends became exercise for me too. And through that process, I found that my running now, in the marathon long distance level, I was able to get stronger and even faster than what I was running in college, even though in college I was doing much more intense workouts. So finding that balance, I was able to understand that less exercise, in a more conscious way, was able to be better for both my performance overall and my long-term love for exercise and running. GRETCHEN REYNOLDS: I'm interested, both from you

19:38 two as athletes and also our researchers-- we have the World Cup coming up and there'll be tons of kids watching the World Cup. It's not easy nowadays to get kids to be active. I'm a parent. It wasn't easy to keep the kids away from screens. Do you have any advice for parents who might want to use sports in particular to get their kids active without getting them burned out, without making them specialize and hurt themselves, without the parents going crazy? Do you have any advice for how sports might be an entry point, and do you think it's a good entry

20:26 point for kids into, hopefully, lifelong physical activity? And, Brooke, can we start with you? BROOKE FORDE: Yeah, sure. I mean, I'm not a parent, but I am thankful to my mom for throwing me in a pool when I was six months old. And the rest is history for me. I think it completely changed how I grew up. Just the fact that my family was active-- and it wasn't like I was being sent to go do a sport. It was always like, the family is going to do exercise together. And so from that standpoint, I think it's really important to make it-- the exercise shouldn't be a chore, it shouldn't be used as a discipline or a consequence or anything for kids when they act out.

21:12 I think it really has to be seen as something the family does together or something the kids get to do with their friends that's more of a reward or something like that, just to make it sustainable. And like you said, there's no need to specialize or put any pressure on performance, things like that. And I think that's, at least in athletes, the ones that end up doing better long term are always the ones that have had less childhood pressure, because they choose, of their own accord, once they're older, to continue doing it and to continue, falling in love with sport and exercise. GRETCHEN REYNOLDS: Would you agree, Mia? MIA SANCHEZ: I agree. I'm not a parent, but I am the oldest sibling out of five.

21:58 And I can say that for my younger siblings, watching them grow up in sports, what really helps is differentiating between sports. So we're not one sport household, although running is very centered to all of our exercises. We do like to do different sports throughout the seasons, and that kind of balances out what my siblings like to do and prevents that burnout for long term. And I think, again, using sports and exercise as something that's fun and that they have the privilege of doing shows my siblings that this is something that's good for them

22:45 long term, that they can do for years and years to come together or by themselves. And they're proud of the work that they do through exercise. As a little anecdote, my youngest sibling is just starting out with summer track, and he's not the very best on his team. But in his most recent meet, he ran a personal best and he told my mom, he's like, I see the work that I'm doing and it's working. I'm getting faster and I'm getting better. And I think that lack of pressure, but still enjoying what he's doing is going to be beneficial for him long term.

23:30 GRETCHEN REYNOLDS: And Meagan, I know you work with a lot of athletes, including NFL people. Would you say too that starting sports at a young age is a good way into physical activity? And then how do you transition back out of it at the end? MEAGAN WASFY: There's research on these topics. But one thing about the research is if what you really care about is keeping physical activity levels high over a whole lifespan, anything we can say about a generation before, because this is a very-- we have a very rapidly evolving society in this regard, you always have to question how it bears relevance in current day. I mean, I think the best we can tell for our current youth, because this is just ambiently less physical activity,

24:16 less playing outside more screens, that a lot of their physical activity does come in structured ways, either through school or through sport instead. So we have to think of those as available tools that we have. One thing, I think, we see consistently, and hopefully across generations, if you have exposure to a lot of different ways of moving your body, you're more likely to find one that sticks. And you still enjoy through midlife, which as an adult cardiologist, that's what I want to continue. And so who knows what makes someone enjoy running versus swimming versus dancing, right? But if you get exposure to all those things, you can think of it as that's your toolbox to pick out from for the rest of your life. So I like that concept. And sports specialization, as such, is a really hot topic in the sports medicine community right now. Because if you narrow down that exposure to just one thing, you might not be exposed to other forms of moving your body.

25:03 And then there is that sort of question of injury and burnout that might leave you actually, paradoxically, leaving your sport before you even hit midlife. And so those are all evolving questions. And in public health, I think, definitely merits more work. I do see both a lot of current athletes and former athletes. And I think, Brooke, something you said earlier, that's an important thing, whether we have people leaving organized sport after high school or after college or after a long professional career. What's the counseling and how can we do better on making sure it's not an all or nothing? It used to be so competitive, but that the idea is, you could imagine then, there's this, well, it's not worth it if I'm not hurting, as Brooke was saying. Really, exercise is medicine. Doesn't need to hurt, right? So the idea it isn't an all or nothing,

25:49 and that even reducing your physical activity from that of a professional athlete, you have to make sure you don't go down to zero, but end up somewhere that's still in a healthful level of physical activity to promote that midlife health and beyond. GRETCHEN REYNOLDS: Most of the exercise and sports and physical activity that we've been talking about so far would be considered aerobic. But how important also is strength training, and doing it deliberately, just making sure that you're doing some strength training? How important is that? And also I'm wondering, I-Min, you might know this, how uncommon is strength training? I-MIN LEE: Yeah, so our guidelines do include strength training exercises.

26:36 And we've known for a long time that strength training is important for your muscles and bones. And so we've emphasized it in older people. But we're increasingly beginning to realize that muscle-strengthening exercises-- And by muscle-strengthening exercises, I don't mean lifting weights alone. You can do things like lifting weights. You can do pilates, carrying your groceries up the stairs. Those are also muscle-strengthening exercises. These kinds of activities, we've seen, I would say, over the last maybe five or 10 years, more data showing that such activities also decrease our risk of many chronic diseases, heart disease, cancer, type 2 diabetes. But we have a lot fewer data on this kind of activity compared to aerobic activities. So while our guidelines tell us do this two times a week, engage

27:25 the major muscle groups of your body, we don't have as much detail on exactly how long we need to do that, and research is still ongoing. In terms of how many people do it. If we look at national surveys, only about a third of the population engages in muscle-strengthening exercises to the extent that is recommended. So this is based on self-reported activity. And currently, self-reports are what we rely on because our devices do not measure muscle-strengthening activities easily. GRETCHEN REYNOLDS: In terms of both muscle strengthening but also aerobic, is there any evidence that it's ever too late to start?

28:10 We were talking about kids, but for someone who might have managed to somehow get through middle age and suddenly is realizing maybe I should be doing something, is it ever too late? I-MIN LEE: So I'll start with aerobic activity first, since we know a lot about that. There is a large body of research showing that it's never too late to start. And in some ways, you can't bank it either. I mentioned Professor Ralph Paffenbarger earlier, and he did some of the very early studies, which were great. He followed Harvard Alumni, and he looked at Harvard Alumni who had been athletic during college and then followed them up through middle age. And it appears that what you currently do is more important than what you did in the past,

28:56 meaning that the Harvard athletes who were playing a lot of sport when they're in college but became couch potatoes, they actually didn't do as well as the people who did no sport in college but were currently physically active, which, again, makes sense, because we know from studies that if you do physical activity, you improve your blood pressure, your glucose tolerance, your lipids. But it's not like this benefit lasts forever. At some point, the benefit from this bout of exercise diminishes. Then you need to do another bout of exercise. So for aerobic activity, it's clear that it's never too late to start. Studies have shown that even if you start being active in your 70s, it is helpful for you. For muscle strengthening activities, there a lot fewer data.

29:41 So we don't know if you start early, you start late, what the difference is. But we do know that there have been muscle-strengthening exercise studies done in older individuals, particularly to help them with their muscles, their bones, their balance. And in these older individuals, so people who had never done or hadn't done much muscle strengthening, in these older people, muscle-strengthening activities was helpful. GRETCHEN REYNOLDS: One of the questions that I frequently get is about the very word intense. Intense exercise. Even vigorous, the word that's often used in the formal recommendations.

30:26 People don't know what that means, and also don't know whether there's an advantage to sometimes doing more intense exercise or not. And what do we know about that? And do you want to start with that one, Meagan, since a lot of it has to do with the heart? MEAGAN WASFY: It's a great question. It's something that comes up a lot. First, I'd say highly intense or vigorous exercise, in our public health guidelines, is on a scale that I like to call absolute, meaning it's the same for Brooke and Mia as it would be for someone who's never exercised in their life. And that just reflects how we collect information from people.

31:12 We can't tell, even through accelerometers, easily whether it feels intense to the person who's wearing the accelerometer. We can just tell how much they're moving. So most of our information about the impact of physical activity on long-term health outcomes is-- what we can say about intensity, it's on this absolute scale, where moderate is brisk walking. And you can generally say anything more intense than that counts, quote unquote, "counts" for double. There's not a triple credit or quadruple credit for high intensity interval training. And from that, and curious I-Min's input, I think that the message we should have the public taking home, about what does intensity mean when we're looking at that absolute scale, is-- what matters is the total amount of human movement, not how we get that dose up, which should make things really

32:00 accessible for our patients. Because whether you're doing things at that moderate brisk-walking level or more vigorous intensity scale, it seems like the health benefits really relate more to the total dose you get up to. It's, of course, more efficient to go faster. You get up to a total dose sooner than to go slower. But that should be empowering for our patients because the details don't matter quite as much. It doesn't matter whether you put it all on the weekend and clump your physical activity together or spread it out throughout the week. Just the total amount you get to is what counts. Now, of course, if you're in a sport and you're training, two things change. One is, of course, your performance is going to vary depending on the intensity of your training. And then we also start to think of intensity in a different way.

32:46 It's all relative to your cardiorespiratory fitness. And that's a very different scale. People talk about things like heart rate ranges or zones. Just know that way of thinking about intensity is divorced from that absolute scale and gets more into sport performance, which is a different space. I-MIN LEE: So can I chime in and say something that's helpful to regular people? So again, not the athletes or people who are training. It's very hard to know what vigorous is if you define it in a scientific context. So if we want to say in an understandable way, what it means to be exercising or being physically active at a vigorous or moderate intensity level, we often use what we call the sing test. So while you're doing that activity,

33:32 you feel your heart going up, you feel yourself perhaps sweating a little bit, and you can't sing, that's considered vigorous. If you are doing this activity, you still feel your heart rate going up somewhat, perhaps you might start sweating, but you can continue a conversation, that's considered a moderate intensity level. So to a layperson, this might be one way that you can figure out what's vigorous and what's moderate. GRETCHEN REYNOLDS: The other question that I get, or comment I get, most often from people when they want to talk about exercise

34:18 is that they started exercising to lose weight, and they didn't lose weight, and now they're never going to exercise again. So I really want to talk about what we know about the role of exercise in weight loss, and then also weight control, which is different, and what people should know about the importance of exercise, whether you lose weight or not. I-Min, can you start with that? I-MIN LEE: Yeah, I mean, weight management is something that's really, really challenging. At a basic level, we know that our weight depends on the calories that we take in, the quantity as well as the quality of the calories.

35:05 And it also depends on the energy that we put out. Now, exercise is a truly dismal and nonefficient way of getting into the negative calorie balance. So I love candy. I can eat a bar of candy in five minutes. But for me to work off those calories, it will probably take me 40, 45 minutes of walking. So thinking that just doing the level of physical activity that is recommended and not being mindful about what we eat, it's really not a good recipe for trying to lose weight. I think what's truly encouraging is we know that physical activity is great for everyone,

35:51 regardless of whether this person has a normal weight, this person has overweight, or this person has obesity. It is very clear, for two people with obesity, that the one who is physically active has a better health profile, risk profile, compared to this other person, with possibly the same weight, who is not physically active. And now, of course, we have the new drugs that help with weight loss. And with the weight loss, there's also loss of muscle, which makes sense, because if you're someone walking around with a larger weight, your muscles are also stronger. And I shouldn't say your muscles are stronger. You have more muscle mass because you

36:37 have to carry that larger body weight. And when people lose weight rapidly, a lot of muscle mass also goes. So I think strength training activities, at that point, is good, because these tasks are relatively new. We still don't know the interplay of physical activity, muscle strengthening with the use of these drugs. But we do know that physical activity and muscle-strengthening activities can help with the muscle loss that occurs when one goes on these drugs. GRETCHEN REYNOLDS: And now I want to return to that very first question that I asked, which is, why do you exercise? And I'm going to expand a little bit on my answer

37:24 because the main reason I exercise, if I'm really honest, is because it keeps me sane. It allows me to deal with stress. And I think there's some really good evidence that exercise has a pretty profound effect on mental health. And I'd really love your thoughts on the role that it's played for you in your mental health and sense of self. And then also any research that we have that buttresses that idea. And Brooke, do you want to start? BROOKE FORDE: Definitely, yeah. I think, for me, one of the most tangible benefits of exercise is just change in mood. And as I mentioned earlier, it's been hard learning

38:12 to use intuition to know which type of exercise to do and really focus on how I'm feeling. And it's hard to-- you come away from a weightlifting session and your body's sore and you might think, oh, why did I do that? I don't feel better, I feel worse. But no matter what type of movement or how my muscles feel after or whether it was cardio or strength or anything, I think I always notice that my brain is just a little bit clearer. I've stopped some of the to-do list running through my head, things like that. Or if I can just get outside and walk in the sun for a few minutes, that's just the easiest thing to note. And so that's one of the reasons that keeps me coming back to exercise on a regular basis is, yeah,

38:58 just the immediate improvements on mental health and mood. GRETCHEN REYNOLDS: Mia. MIA SANCHEZ: I definitely agree. I think, with running being so ingrained in my life, and I've been running since I was 11 years old, so it's definitely become an outlet for me. With school, I would take either 20 minutes or an hour more just to go outside and step away from my academic work and my computer, and it was a great outlet for me in terms of the stress and that balance of exercise in life. And then I think it's been a great opportunity, like social,

39:45 to have teammates that I trained with, but also going and playing volleyball or soccer with my friends, like mentioned before, and having that sort of outlet that way where I'm getting to have time alone, but I can also spend that time exercising with others. GRETCHEN REYNOLDS: And Meagan. But both as a clinician or researcher and personally, what role do you think exercise plays in mental health? MEAGAN WASFY: Oh, I mean, for me personally, it's my calm time and space. And so I can just affirm what others have said. I'm an entirely grumpy human who doesn't function well on any level if I'm not getting regular physical activity.

40:31 And that includes-- I love my running, but also things just a walk around the block or bicycling or anything. So you can see it from any form. And that's where I think capturing people, like having individuals in the public at large, capture what form of human movement just aligns most with whatever that is, what they enjoy The social aspects to sport, we know, in general, what are the lifestyle factors that we can utilize to improve overall health and heart health. I mean, physical activity hits so many of them. Mia and Brooke just hit on some of these things. So we, in general, see associations between stress and cardiovascular disease, quote unquote, "type A" personality. Colleagues of mine have imaged the activation of the amygdala, the emotional center of your brain,

41:17 and shown that relates to the inflammation of your arteries, right. That mind-body connection, you can see it. You can image it. And we know that physical activity can reduce stress, right? We all just said we experience it. And then in general, in societies where we see better social connection, we see better longevity. And it's hard to know the exact mechanisms of that. But if physical activity and doing sport together can help on both those fronts, these things are all interrelated to each other, is what I'm saying. And then you also see physical activity impact almost all the risk factors for heart disease, some more so than others. And what I like to say to patients, because we were talking about weight, is that-- let's say you started physical activity for one goal. You wanted to lose weight. Your blood pressure was a little up. You wanted to avoid blood pressure medicine, something

42:04 like that. And you start up from a couch to 5k, sort of nothing to a good dose. And the thing you're focused on doesn't change, which would be disappointing. Weights the same or blood pressure is the same. Despite those efforts, I always emphasize that physical activity program is impacting all these other things we can't measure. So don't stop. Don't stop it just because it didn't influence the thing that might have been the carrot on the stick to start it to begin with. So whether that's something we can measure in the office or something that's harder to measure, like stress levels or social connection, those are all benefits. GRETCHEN REYNOLDS: And I-Min, would you like to chime in? I-MIN LEE: Sure. So I agree with everything that Brooke, Mia, and Meagan said, and for me personally, this time of year, it's just so great. The flowers are all out. It's bright, when it's not a rainy day.

42:52 The birds are singing. So that's wonderful. And we do have a lot of data clearly showing that physical activity improves your mental health. I'd also like to pick up on some of the points that the others brought up, which is the social aspect of it. So there have been some studies that look at the types of sports and how it benefits health. And interestingly, tennis seems to be the activity that may be more beneficial compared to the other activities. But as Meagan said, I believe it's actually the energy expenditure. And maybe with tennis, it's that the investigators were not quite capturing, perhaps, the social aspect of that sport. And also that this is a sport that you could probably continue until you're older in life.

43:38 So the social aspect of the sport, definitely, I think makes a difference. GRETCHEN REYNOLDS: Well, this has just been a terrific conversation. It's very inspiring. I'm actually going to gather up my dogs and go for a walk after this. So thank you all for joining us. This was terrific.