In this episode, Seth McCarthy, (he/him) a PhD student in the Department of Kinesiology and Physical Education at Laurier, and is part of Dr. Tom Hazell’s Energy Metabolism Research Laboratory. His research focuses on the role of lactate, a substance produced in the body when we exercise, and when/if/how we experience hunger after exercising.
The episode features:
WLU Research Chat S03 Seth
Unknown 00:00
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Shawna Reibling 00:04
Welcome to the third season of Research Chat. In this season graduate students share the challenges of their research work.
Shawna Reibling 00:14
In this episode, Gabe Massarotto will interview Seth McCarthy about his research. Thank you to both for chatting with me today. First, I'll introduce you and then I will turn the microphone over for your interview to begin. Gabriel Massarotto, who uses pronouns he/him, is a current Masters of Science and Kinesiology student at Wilfrid Laurier University, where he received a Bachelor of Kinesiology. Gabriel's primary research interest is exploring the effect of exercise on functions of the brain such as memory and learning. He was awarded two Undergraduate Student Research Awards, which allowed him to complete research projects during his undergraduate degree. One project included conducting a literature review regarding the effects of various types of exercise on the health and functioning of individuals diagnosed with mild cognitive impairment or MCI. Gabriel is actively involved in the community working alongside organizations that provide physical activity programming to populations experiencing cognitive and or physical impairments in their everyday lives. He previously worked at Supporting Neurodiversity Through Adaptive Programming or SNAP, which is a support program affiliated with Brock University. At SNAP, developmentally appropriate physical activity programs are designed and then administered to children and youth with disabilities. In addition, he is working with the Alzheimer's Society. The Alzheimer's Society, like SNAP encourages individuals who experience cognitive impairments to become physically active through their minds in motion program while connecting with their peers to enhance their overall well being. Gabriel hopes to further his education and practical experiences in Rehabilitation Sciences to assist individuals living with disabilities. Seth McCarthy, who uses pronouns he/him, is an exercise physiologist and nutrition researcher who's pursuing his PhD in Kinesiology at Wilfrid Laurier University, a specialist in appetite regulation and how it is affected by exercise. Seth has over five years of experience working in the Energy Metabolism Research Laboratory supervised by Dr. Tom Hazel. While Seth's work is mainly focused on improving our understanding of exercise induced appetite suppression in hopes of using exercise to suppress appetite and lead to weight loss. He has also studied how exercise affects post exercise metabolism and blood pressure, as well as how different types of exercise training can improve fitness in adults. Seth received his Bachelor of Human Kinetics from the University of Windsor in 2018 and his master's of Kinesiology from Wilfrid Laurier University in 2020. He currently holds the Alexander Graham Bell Canada Graduate Scholarship at the doctoral level from the Natural Sciences and Engineering Research Council of Canada and has previously held the Canadian Institutes of Health Research Canada Graduate Scholarship at the masters level, as well as Ontario Graduate Scholarships at the masters and doctoral level. In addition to Seth's research ventures, he has worked as a contract teaching faculty member in the Department of Kinesiology and Physical Education at Wilfrid Laurier University Teaching exercise nutrition to third and fourth year undergraduate students as well as speaking to different audiences about exercise and nutrition. Thank you so much for chatting with me today. I will now turn the microphone over to you Gabe to interview Seth.
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Gabe Massarotto 03:34
Hi Seth, thanks for chatting with me about your research today. I'm very interested to hear about your research project and some of the experiences with your grad school.
Seth McCarthy 03:42
Thanks, Gabe. I'm looking forward to sharing a little bit more my research and chatting with you today. So we obviously share the same research laboratory but, can you tell me a little bit more about how you fit in it, as well as how your research fits into the particular program? Yeah, so I am a member of the Energy Metabolism Research Laboratory, or I'll call it EMRL for short, and this is run by Dr. Tom Hazel. Now the main focus of the EMRL is looking at how exercise affects appetite. However, we do do other work looking at adaptations to different types of training, as well as how exercise affects metabolism during and in the hours after exercise. My research specifically is focused on one specific mechanism for how we believe exercise affects appetite, and that is lactate. If you listen to Gabe's podcast, you'll have an idea of what this is otherwise, we'll get into a little bit more detail on this later.
Gabe Massarotto 04:37
So obviously you're interested in exercise as well as appetite. But what particular question do you when to endeavor or research further?
Seth McCarthy 04:47
So my main research question is to try and determine how lactate affects appetite, specifically in reference to exercise. So during the transition from my masters to my PhD, I worked on a project where we summarized information from a number of different studies. Most of these were done in mouse or rats and some were actually done in cell culture studies, which is basically petri dishes. And from these studies, we've put together a host of information and we hypothesized three different ways that lactate may be suppressing appetite. However, these were just hypotheses, and these haven't been tested yet. So the focus of my project is to test these hypotheses and see if they actually occur following lactate generation with exercise, or following the ingestion of lactate.
Gabe Massarotto 05:33
So obviously, both of us have common ground so, we're both interested in lactate as a molecule. So what exactly is lactate in your own words? And how does this work in the body?
Seth McCarthy 05:45
So lactate is a molecule produced in our body when we're using glucose to create energy. So the faster we need energy, the more lactate we produce, and an effort to create that energy. And when the rate at which it is produced exceeds the rate at which lactate can be used and that is, for example, as an energy source in the heart in the brain, it then begins to accumulate. So for example, during maybe a 30 minute easy bike ride, would likely resulted in little to no lactate accumulation. Whereas if you were to go and do hill sprints, or some sort of hard interval exercise, this would result in significant lactate accumulation. So for my research, lactate is important because it appears to be an important factor in how exercise can suppress appetite, and potentially result in individuals eating less during the exercise.
Gabe Massarotto 06:36
That's very interesting, because, for myself, I typically eat lots of food, and don't really seem to suppress my appetite at any point. But obviously, for our viewers, and our audience, I think it's important for all individuals to understand why or how lactate can suppress their appetite. So going further into that question, how exactly do you plan on exploring this research question?
Seth McCarthy 06:58
So to explore my research question, we'll be manipulating lactate and multiple different ways, and then measuring different markers of appetite. So in studies in which we use human participants, we measure different hormones in the blood that can affect our appetite. We measure individuals perceptions of appetite, like, how hungry do you feel? How full do you feel? And we also measure how much food or energy individuals consume. So this provides us multiple layers of data ranging from something that's very objective, like the hormones in our blood, to something that's more subjective, like how we feel and the food that we actually consume. However, specific to my question, we're a little limited with how in depth we can assess this, because we can't actually measure appetite signals in the brain in humans. So one of my studies will be completed using mice and this will allow us a more in depth exploration of the effects lactate and exercise have on appetite. We can measure different signals and proteins in the brain that are related to appetite. So in this study, we'll measure different hormones in the blood, as well as the amount of different proteins involved in appetite signaling pathways in the brain, we will also measure the amount of food that the mice eat after they've completed the different conditions such as exercising, exercising with a drug that would block lactate production, or after having lactate injected.
Gabe Massarotto 08:23
So I noticed that you touched upon objective and subjective methods. So obviously, qualitative and quantitative methods. In my opinion, sometimes it can be very difficult to branch or merge these two particular fields so, how did you overcome that for yourself? And how did you work your way into a mixed methodology research study?
Seth McCarthy 08:45
So these technically are still quantitative methods, because our end goal, or value or data is still numbers. So when we assess people's perceptions of appetite, we use something called a visual analog scale. And basically, this is a 10 centimeter line with opposite ended answers. And a question like, how hungry Do you feel? One end of the line is, "I've never felt hunger", the other line is the opposite, "I'm not hungry at all". Individuals would put a perpendicular line through that 10 centimeter line. And basically, we have these different questions that we can use to assess appetite from which we can generate an overall appetite score. So still on the quantitative side of things.
Gabe Massarotto 09:29
Perfect, I think you answer that question very, very well. So obviously, we have not discussed this yet, but I'm aware that you have collaborated with other researchers. So what are the benefits or insights you've gained from working with other peers across multiple labs within the Department of Kinesiology?
Seth McCarthy 09:47
So I think in our department, there are a lot of nice opportunities for collaboration. Some that specifically I've been involved with throughout my Master's and PhD is with some of the sport and exercise a psychologists in our department, and we've looked at manipulating different types of high intensity exercise, and trying to figure out how we can manipulate exercise in a way that it's still effective but people have greater feelings of enjoyment and confidence following the exercise in hopes of increasing the likelihood that individuals are participating in exercise. So these experiences have been very valuable, as I've been able to see how other researchers approach different problems. And this has really just provided me with different perspectives and different lenses that I can use when I approach my own research.
Gabe Massarotto 10:38
I think what's nice about Kinesiology is that it's multidisciplinary. So we essentially collaborate with other researchers who have very unique perspectives. And at the end day creates a very, very unique research project. Now, obviously, in research, and as researchers, we typically face many, many, numerous challenges. So, can you elaborate on some of the challenges you face during your own research, as well as any challenges that you may have faced during your own field work?
Seth McCarthy 11:08
So as a grad student, one of the largest challenges for me stems from the COVID-19 pandemic. So as the type of work that I do is in a laboratory with volunteers from the community, the lockdowns did disrupt my ability to progress throughout my master's degree and into my PhD. So I spent most of the first two years of my PhD trying to finish up studies and wrap up studies that were delayed due to COVID. However, I was obviously not the only person in this scenario and most other students doing personal research throughout Ontario, and the rest of Canada were affected similarly. But then in terms of specifically the types of methodology we do, the greatest challenge here, I would have faced would have been learning some of the different biochemical techniques that we use to look at the amount of different hormones in the blood samples we take. So just briefly, we have these kits that involve a series of different steps where we add different chemicals and solutions to the blood samples that we've collected. And when there's a high amount of air in the data, it unfortunately can't be used. And then that blood sample that we have, which is limited, and the 500 to 700 dollars, it cost to buy one of these kits is wasted. So it took me a while to be able to refine my technique, and reduce the amount of air to the point where the data that we had was usable. And this was frustrating, because it can be kind of difficult to determine where you went wrong, and how or why the air was so high.
Gabe Massarotto 12:32
So how essentially, did you get over that frustration?
Seth McCarthy 12:36
So part of that was one reaching out for help, and connecting with a prof in our department that had a little bit more experience with the biochemical side of things. And he was able to come in and walk me through things and give me some different tips and pointers. And then the other thing was just practicing, making sure that I was spending a little bit of time every day or a couple of times per week, practicing pipetting in particular, which is generally the reason for higher air. So I was just practicing a lot and making sure that I was consistent and accurate before I began doing more of the different kits.
Gabe Massarotto 13:11
So up until this point, we've obviously had a very thoughtful discussion about whether that be our methods, challenges, and etc. But what are your next steps in your work? And how do you plan on furthering where you are now and extending that further?
Seth McCarthy 13:27
So the next steps in my area of work would be to specifically improve understanding of how exercise affects appetite. There's a lot of research that suggests exercise can affect appetite, and it's different hormones that we measure. But we're specifically interested in how so that we can improve our understanding, which will hopefully allow us to design exercise in a way that can suppress appetite and help individuals lose weight. Specifically regarding my topic or my research question, lactate and appetite, once we better understand the acute effects of lactate and appetite, we'll have a better idea if some sort of lactate supplement, or exercise that generates a large amount of lactate could be helpful to curb appetite, again, with our main focus being on helping individuals maybe maintain weight loss or lose weight.
Gabe Massarotto 14:14
So, springboarding off what you just said, obviously, with the weight loss, how can you place your research in the broader context of exercise for weight loss specifically?
Seth McCarthy 14:24
So there's a lot of discussion as to whether exercise is beneficial for weight loss. And there's data that suggests weight loss to exercise is quite variable, and that two individuals could do the exact same exercise intervention and one could see changes in weight and one may not see changes. But much of this research focuses on low to moderate intensity, something like a casual jog or bike ride. These types of exercise, burn a large amount of calories during exercise, but have little beneficial effects following exercise. Whereas high intensity exercise such as doing sprints on a treadmill, or going for a hard run where maybe you can't keep up a conversation with someone you're running with. This type of exercise burns fewer calories during, but has a number of beneficial effects following exercise. So hopefully as there's more long term studies, looking at high intensity exercise and exploring if weight loss is less variable with this type of exercise.
Gabe Massarotto 15:18
So as we begin to wrap up our conversation, if an audience member approached you and said, Hey, Seth, what is the key message of our conversation? What would you say is the key message about our whole conversation?
Seth McCarthy 15:30
So I think the key takeaway for our listeners to remember about this topic is that higher intensity exercise, where for example, you wouldn't be able to keep up a conversation with someone beside you suppresses appetite more than lower intensity, casual exercise. But with that, in mind, the best type of exercise is the type of exercise that you enjoy, and that you'll do. So regardless of whether that is low, moderate, or high intensity exercise, I would suggest that people incorporate exercise into their life, so that they can benefit from all its great effects.
Gabe Massarotto 16:01
So I think, typically, a lot of people fear high intensity protocols. But how can we incorporate a high intensity protocol, but yet ensure that it is still tolerable?
Seth McCarthy 16:11
That's nice question, Gabe, and I think there's a lot of misconceptions with different types of high intensity exercise. So something to keep in mind is generally the higher intensity that you're working at, the duration you're exercising is likely going to be shorter. So generally, we're not working for a prolonged duration. Quite often different high intensity exercise protocols are designed with different durations of work and rest. So for example, you may run for one minute and then rest for a minute. And you may repeat that for 20 minutes in total. Another popular thing right now that we're seeing in the research is very short, hard periods of exercise split up throughout the day. So for example, 15 seconds of exercise, at eight o'clock, 12 o'clock, and four o'clock. And that could be something as simple as running up your stairs two times, or potentially just doing one short lap of your street. So really, I think there's some misconceptions and generally, the harder you're working, the shorter duration that will be for and then you'll have a longer period of rest, which can allow these types of exercise to be more tolerable and things that we enjoy doing.
Gabe Massarotto 17:18
I think you summarized quite well and the need or importance of breaks, sloughs periods for us to recover, because obviously, we cannot sustain these high intensity bouts for extended periods of time. So thank you, Seth, for sharing your research with me today. It is very interesting to see a very different side of lactate and its functions. There's also a very fascinating to comprehend that high intensity exercise may help to minimize our desire to indulge, which I'm sometimes guilty of.
Seth McCarthy 17:49
Thanks for the chat, Gabe. It was nice to share some of my work and have a great discussion.
Shawna Reibling 17:54
Thank you to you both for sharing your research. It's exciting to learn more about how research and memory are related, and how different intensities of exercise can really matter when it comes to maintaining or losing weight.
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Shawna Reibling 18:14
I hope you enjoyed listening to today's discussion. If you'd like to learn more about exercise and memory and how exercise affects the body, listeners like you are encouraged to share these episodes, and use these episodes to discuss the topics with your friends, your family, or as an assignment in the classroom. There are resources, additional readings and details about the work of each researcher on the website wlu.ca/research-chat. The next series of episodes will feature a different pair of graduate students sharing their research experiences throughout their graduate work at Laurier. Subscribe on your favorite podcast platform to be notified of new research chat episodes. Research Chat is a partnership between the Office of Research Services, the Faculty of Graduate and Postdoctoral Studies and the Laurier Library. Thank you to everyone who's contributed to the creation of Research Chat. A gratitude list can be found on our webpage.
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