Doctoral Student Rosie Perez Discusses Her Work in the Heat and Hydration Optimization Lab in Latest Short Talks

Hardin Young: Welcome to Short Talks from The Hill, a podcast from the University of Arkansas. I’m Hardin Young, a research and economic impact writer. This month we’ve invited Rosie Perez, a second year Ph.D. student in the Department of Health, Human Performance and Recreation, to come in and tell us a little bit about her ongoing research. Perez is based out of the Heat and Hydration Optimization Lab, also known as the H2O lab, run by associate professor Brendan McDermott, an authority on the factors contributing to, and the consequences of, heat illness. Rosie, thanks for coming in.

Rosie Perez: Thanks for having me.

HY: First off, what does the H2O lab look like and what kind of work are you guys doing down there?

RP: Well, we do a wide variety of work. Since there are three doc students in there, we each have a little area of research we are interested in. My lab mate Sean, he’s very interested in how endurance performance is impacted by heat. So, we do a lot of sweat testing. He’s going to gear up to do some work with, hopefully, the women’s track team and see how that plays a role and if there’s any ways we can improve their nutrition to impact how they perform. Then my other lab mate, Jack, he does occupational health. So, we take guidelines like the NIOSH (National Institute for Occupational Safety and Health) guidelines that have like heat guidelines that tell us, ‘okay, in this climate, how much work can they do? And then what rest do they have to do to follow up and then how much do they have to drink?’ And so he looks at how that plays a role, because if you can’t work you’re not going to be productive. And then I am the last one and I get to merge my background of working with tactical athletes, so firefighters and law enforcement, and kind of see how environmental physiology plays a role in their jobs. Since I have a strong background in strength and conditioning, I get to apply that physiology standpoint I look at here and then apply it into how I program for them so that they’re more prepped for what they’re going to do.

HY: To study this you need people. So do you have subjects coming into the lab? How does this work in practice?

RP: A lot of the time we recruit students on campus because it’s an easy access point for us. We’ll have them come into our environmental chamber and we’ll set it to a certain environment. So typically we look at either a warm, humid climate or a hot, dry climate just to see if there’s differences there. With my research, I get to partner up with local fire departments and actually bring their firefighters in, which I enjoy because I get to see them, but I also get to ask them questions, like, ‘Okay, how can I help you with your research?’

HY: I read the news and there’s always requests for test subjects on campus. You know, they want you to do taste tests or they want you to do sleep tests, but this actually sounds like it could be a little grueling. Seems like you’re going to be testing people’s endurance and their capacity to withstand heat, things like that. Is it difficult to get people to come in?

RP: Sometimes it is. One of our safety components is a rectal thermometer. And so we have to have them use that so that we can measure the core temperature in case they get too hot. So that usually turns a lot of people away. And then the other one is we’re lucky that my lab mate Sean, he knows a lot of people who do ultramarathons and those high endurance activities. And they’re like, ‘we’ll come in and participate,’ so that helps a lot with his studies. What I’ve learned with tactical athletes, they’re very interested in helping with research if it benefits them, because they really want to get better, they want to be able to do their job with less injury. So, it’s usually pretty easy to ask them to come in.

HY: So let’s get into that. How did you end up doing research with Professor McDermott? And you know, what path did you take to get here?

RP: I was a freshman at Oklahoma State University and they have a service learning component of their courses. And so we had a brand new professor start that year. And he had started doing research with the ROTC program. And so we would go out there and help with their P.T. and training. And I just loved it as growing up in a military family, I saw how much the military impacts the body, and so it was a nice way to do that. And then I started to become an EMT because I was potentially looking at med schools. And once I became an EMT, I worked with some firefighters and one of them was taking fertility drugs while she was doing it. And from my knowledge of fertility drugs, one of the things it says is to stay away from excess heat. But as a firefighter, your job is to fight excess heat. So I was like, ‘how do we protect them and allow them to still do everything everybody else gets to do, with the precautions they need?’ And so that started making me realize that med school might not be what I wanted to do. And so I started looking at Ph.D. programs where I looked between tactical labs and then like thermoregulation labs. And that’s how I stumbled upon Dr. Brendan McDermott. And I sent him my CV. I read some of his articles that he published, and I was like, ‘hey, these are really interesting. Would you like to meet up?’ And so we did. And he was very impressed by my CV. And so it gave me like hope that I can do it. And so after going in and out throughout the last year of my masters, I ended up confirming to come here and it’s been pretty great.

HY: Just out of curiosity, did you take any time between your undergrad and master’s or between your master’s and here?

RP: I’ve been straight through for all of it. I had a really good scholarship that gave me five years of free schooling, so I ended up paying for my undergrad and my masters through that.

HY: And you were an EMT almost that entire time?

RP: The last three years. So my last year of my undergrad, and then my two years of my master’s.

HY: You’ve talked about it a little bit, but let’s dig into it. What is the subject of your Ph.D. here?

RP: So my subject in my Ph.D., I have two areas. So one, I look at how heat stroke is being handled out in the real world. So, kind of with that, I recently published a paper saying that exertional heat stroke and classical heat stroke, even though they show up in different populations, their pathophysiology is similar and so we should treat them the same. And so that kind of goes into a little bit of why are they not being taught the same? Part of it is looking at protocols. So their states might have a certain protocol that they say they use. And then when you start looking at actual agencies, not all of them follow that protocol.

HY: Can we back up just a tiny bit? Can you just define exertional heat stroke and traditional heat stroke? Because I think most people probably just think there’s only one kind.

RP: So exertional heat stroke means that we have a physical activity. So typically we see in athletes they produce a body heat above 40°C, so about 104°F. And so they typically will end up passing out. They lose some consciousness. After a while, they become very combative because they don’t know what’s happening around them. And so the point is to cool them. And then with classical heat stroke, we’re going to see it’s passive. So when there’s a heat wave, like down in Texas, and it’s above 100 degrees all week long, they don’t have access to air conditioning, then they can get exposed to that 40°C, so that high heat and that causes them to get a classical heat stroke.

HY: And you said these have been treated the same way typically or different ways?

RP: Different ways. So with classical, a lot of people, since it happens in either pediatrics or older adults, they’re like, ‘oh, if we immerse them in cold water, then they’re going to go into shock because of it.’ And as we’re starting to see, there is data showing that actually immersing them in cold water gives them their best shot, so it lowers that mortality rate. And then the other one, it gets them cooler quicker. So that’s what we really want is to have them cooled so that they don’t cause any more damage.

HY: Getting back to your thesis, you said that’s one part of it…?

RP: And then my other part is looking at how heat stress plays a role in tactical athletes. Right now, I do it predominantly working with firefighters because that’s who I have the most access to. And so we currently are looking at how cardiovascular disease is a common development in firefighters. So we want to see how can we mark when that’s occurring. And so like we’re doing a lot in general study where we have from the youngest being 18 all the way up to 47 and seeing how their cardiovascular measurements are changing throughout time.

HY: So a couple of things here. One, it sounds like Dr. McDermott is giving you a little latitude here on your Ph.D., because that sounds like it’s a little outside of heat and dehydration?

RP: He is. When I came into the program he was very much like you help with the lab, which I do, and then we can help you develop your research niche. So that’s kind of where the cardiovascular measures come in. Partially why I also want to know those is hopefully for my dissertation I’ll get to work at how live fire training impacts them. So we’ll actually see them do fire tasks and look at what’s their physiological heart measures, what is happening there, what is their hydration there. And then even look at their kidneys and see, are they developing any buildup of metabolites in their kidneys that they need to flush out?

HY: People might be able to guess the answer, but when you’re talking about EMTs, firefighters and people kind of in these stressful situations having higher instances of cardiac arrest, can you kind of just talk about why that is?

RP: Well, there’s a lot of factors that go into it. So one of them is going to be sleep because they don’t know when their calls are going to come in. That does impair their sleep. Another one is diet. Sometimes they do have time to make healthy meals and other times they don’t. So it’s interesting seeing how that plays a role. Another thing that’s really high in them is their overuse of caffeine. So, typically we see a high number of tactical athletes using more than 700 milligrams of caffeine, which that puts a lot of stress on your body. And then the last one is their physical health. So are they actually fit for the job? Some of them, they do a great job. They work out. They continue doing what they need to do so that they can do every task of their job, while others they might not because they’re really busy, because when they get home off a shift, they have family, they have children. And so it’s hard to develop an environment that’s always friendly to exercising. And then the other one is when they are at their stations, are they built up for them to actually get a good workout in. Or some of them, if they’re used to being sore a lot after they workout, they might not want to work out because they’re like, ‘well, I don’t want to be sore when I have to go do my job.’ And so it kind of needs to find a way where we can balance all of those markers. And then there’s just genetics. Like if they’re already predisposed to cardiac conditions, then they’re at a higher risk of that.

HY: Alright, so the answer is a lot more complicated than just a stressful job. So how much more do you have to go on this? And what do you think will be the next steps?

RP: So, while at the university I have two more years. So hopefully I continue doing studies and looking at different parts of how heat plays a role. And then after this, I will hopefully get to find a postdoc so I can get more grant work experience before applying for faculty jobs.

HY: So where do you see your cardiac disease study going and what’s next?

RP: I would love to continue that. Just because we do need to kind of know when it’s developing and how long does it take. Because then that can help other people program and train them better. And then also potentially help rework their insurance to actually fit more of what they’re going to do. With the future, I really love and hopefully will start getting more into female physiology. I think that there’s a big lack of it. People are starting to publish, people are starting to do more. But in my field, a lot of the times why people don’t use females is they say, ‘well, their hormones impact their thermoregulation.’ So that’s why they didn’t use a female, which isn’t a valid way to do it. And then even though they’re a small number in tactical athletes right now, it’s like 10% of firefighters in the U.S. are females. It’s so little. But if you can apply it to just normal females and then be like, ‘here’s how they respond to the heat, we can apply it to your job.’ So hopefully I’ll start to get into that and start to understand how that’s playing a role.

HY: Let’s just ask some super broad softball questions. First of all, what do people get wrong about hydration?

RP: Well, partially, a lot of people get wrong that they’re like, ‘oh, we have to drink so much water to stay hydrated.’ It varies depending on the person and how much activity you have. And then with athletes, we tell them ‘drink water, drink water, drink water,’ which can be a slight problem because they need those sodium and electrolytes we lose in sweat. And so we want them to actually drink more carbohydrates. We want the carbohydrates with the sodium so that they can actually refuel better. A lot of endurance athletes when they go do hours of work, they’re like, ‘oh, I’m just going to drink water.’ And we’re like, ‘no, no, no, drink some carbohydrates so that you can actually feel better during the workout.’

HY: When you’re talking about drinking carbohydrates, I assume you’re not talking about Gatorade?

RP: Gatorade, Powerade, they all have carbohydrates in it. They all have worked on how much carbohydrates can we take in. So those are actually what we want. We want them to drink those kind of drinks.

HY: With summer coming, what are your recommendations for people who may have to work outside or want to stay active in the heat?

RP: Build up your tolerance before going out. So we have this thing called heat acclimatization. So what this means is each exposure you get to the heat will actually help you feel better. And so it allows you to increase your plasma volume, which you need because that allows you to sweat more. And so we want people to slowly, if they can avoid being out there from like 10 to 2, because that’s when it’s the hottest and try to move towards early in the morning or later in the night. So, they’re a little bit cooler. Another false thing that we talk about a lot is people say stay away from dark colors. There aren’t actually any studies saying that wearing dark colors in the heat is going to cause you to be hotter. So, we’ve seen studies that look at actual like the shirt is hotter, but when wearing it on a human, there’s no study saying that that human is hotter. So it’s like, ‘well, you probably don’t have to worry about that if you want to wear that color, a black t-shirt outside, then go ahead.’

HY: This may be beyond your expertise, but I’ll just ask. Your recommendations sound great for an athlete that maybe can acclimatize like you’re saying, but I see these poor guys in summer doing road work, so what kind of clothes should they wear?

RP: I would recommend them wearing some thinner clothes. So like a lot of dry fit because we want their sweat to come off of them. The evaporation of sweat is what’s actually cooling us, so not trapping the sweat in. They can actually work on exposing themselves. So, before it gets really hot, have them start going outside. Start when it’s a little bit cooler, above that 86 degrees, start staying outside for a little bit longer because that will allow their body to adjust. So that heat acclimatization would occur with them, too. If they can mimic some of the work they’re going to do, they can also do that prior to them getting into the long hours, and then with those long hours, making sure they’re drinking enough electrolytes. So the Gatorade is going to be important for them. Water is going to be important for them. So, making sure they have enough fluids to stay hydrated.

HY: Rosie Perez, thank you for coming in.

RP: Thank you for having me.

HY: Short Talks from the Hill is available wherever you get your podcasts. For more information and additional podcasts, visit ArkansasResearch.uark.edu, the home of science and research news at the University of Arkansas. Music for Short Talks from the Hill was written and performed by local musician Ben Harris.