Hello and welcome to everyone today for joining us for today's webinar presented by AECOM and AIHA, Enhancing Workplace Health and Safety with Physiological Monitoring. We're thrilled to have you join us for today's important and timely discussion. Before we begin, let's cover some housekeeping details. There are two features available for communication during this webinar. We have the chat feature, which you may post general messages in the chat. Messages can be shared with either the panelists or all participants. Use the drop-down menu to select that audience, and you can do so by starting to introduce yourself and letting us know your role or where you're located from. We will handle questions at the end of today's presentation via the Q&A box. Questions from the panelists should be submitted through the Q&A box located on the bottom of your screen. This is the best way to ensure your questions are seen and addressed. Please avoid posting questions in the chat. Also a reminder, today's webinar is worth CME credit. You are required to have an AECOM username and password. Following this webinar, I will send out instructions on how you can claim that credit. You'll need to complete the evaluation, and more details will be shared at the end of today's presentation. And now I'd like to introduce and welcome today's speakers. We are delighted to have Dr. Maggie Morrissey-Bassler and Dr. Kenji Saito as our faculty today. They'll be giving us a more in-depth look on today's topic, and I'd like to welcome them and do a quick introduction. Dr. Kenji Saito is immediate past president of AECOM and past president of NECOM. He's assistant clinical professor at Dartmouth and on faculty at the University of Penn and Harvard University. Kenji enjoys training the next generation of leaders in occupational health, safety, well-being, leadership, and organizational development, digital health, innovations, data analytics, entrepreneurship, Medco legal consultant, and bioethics. He is a consultant and advisor for employee health and wellness to several national and global companies in consumer products, marketing, transportation, manufacturing, pharmaceutical industries, and working with various government and regulatory agencies. As a physician, he continues to practice clinical occupational health, seeing pilots as a senior medical examiner for the FAA, and as an attorney, he is barred in the Commonwealth of Pennsylvania. During his spare time, he enjoys serving as one of the founding board members of the Kids Chance of Maine, Maine Medical Association, and House of Delegates to the American Medical Association. Dr. Saito is currently the global chief medical director of Owens Coring and previously a senior director of global wellness at P&G. Welcome. Dr. Maggie Morrissey-Bassler is assistant professor of the health and sciences at Providence College and the senior advisor of occupational heat safety at Corey Stringer Institute housed at the University of Connecticut. She has over 35 peer-reviewed publications on heat stress, worker health, and hydration. In 2020, she led a 51-expert roundtable on strategies and resources to protect workers' health, safety, and productivity, which resulted in a consensus document used to inform OSHA's heat stress regulation. She serves as the chair of the Thermal Stress Working Group at AIHA and a subcommittee member of the recently published ANSI-ASSP, a 10.5 heat stress construction voluntary standard. She has consulted with numerous organizations such as UPS and Delta Airlines to improve their heat stress management plans. She has dedicated her career to providing evidence-based guidelines to protect underserved working populations from heat stress through the research and education initiatives. And I'd like to welcome and we'll have Dr. Saito kick us off today. Wonderful. Well, good morning, good evening, good afternoon, depending where you are in the world. Looks like we have a great attendance today from all over the world, looks like from the chat I'm looking right now briefly. So I'd like to get started. I'm going to ask you to take out your phones or if you're on your computer you can do this and actually leave it on. This is going to be very interactive. As you give me feedback, I'm going to tailor a talk specifically to what your needs are and hopefully we'll have a good discussion at the end, really tailored to what you're looking for out of this talk today. So there's a QR code you can see at the bottom right and left here. It's also in the chat. Please go ahead and log in and let's get tested and see if this was working or not. And we'll make this very interactive. So here are some of my conflicts of interest and disclosures. I do have different employment and consulting as well as private equity and different businesses as well. So let's see. I always like to start off with this question. So not only is it an icebreaker, get an idea of what we look like in the field that we work in, whether it's in occupational medicine, occupational health and safety, and you can see here we have a lot of seasoned folks, right? I'm not saying your age, I've learned not to say old, I've learned to say more seasoned because it is about seasonality, especially in the field of what we work in and relate to heat stress, heat strain, managing what we do for protecting worker safety around the world. The experience level, and I've seen this all over, is that it's quite mature. You can see about almost half of us are 21 plus years. The question is, when you're ready to retire or step away, is the next generation ready to pick up where you left off? And this worries me a little bit, right? We need to focus on our future generations of trainees. And I'd like to share this data back later on and we can see how this might change with time. But I think this is an opportunity like today, sharing a webinar between AECOM and AIHA, this is our second in our series, hoping to do more of this so we can start educating the world around worker safety and protection. So thank you for what you do and continue doing the great work you do. This next question really asks not only of your experience, but what do you do? This is more like a social media. So if you're a safety professional, click the thumbs up and I'll count you in. If your profession is not in here, please go ahead and type it in and let's get the vote going and see how many industrial hygienists are here today as compared to some of our physicians, safety professionals, our nurses, nurse practitioners. We have physician assistants, it looks like, some safety professionals. So this is wonderful. It looks like a majority of us are industrial hygienists, which is great, right? This is why we have Dr. Morrissey on with us today. I'm really honored to be on a panel with her, with her expertise in heat stress and heat related impacts on the workplace. I think it's going to be really good that we tailor it to them. So I'll keep the medical lees and the sort of legal lees to more of a simple, basic foundational knowledge base. But we'll focus a lot of our talk today for our industrial hygienist friends. So I'm glad this partnership between AECOM and AIHA is working very well. I hope to do more of this. So wonderful. As people kind of log in, just remember, we're trying to use a lot of the live polling. You can see the QR code top right, or you can type into your browser or use your phone. But it seems like it's working pretty well. We have a good attendance today, and I think we have over 700 people who registered for this. So let's get us going. Now that I know, so most of us, what we do, how about what industries do you work in? Same here. Let's get people used to the system as well. What industries do you serve or you work in? It seems like some of us are consultants as well, so you probably have a lot, but I'm just curious to see what industries, kind of majority of what we do. And I assume, since the numbers aren't changing, that there might be some sort of hiccup in our system. Let me just see if I can move forward a little bit, and I'll bring it back here. And let's see if you're able to type in and work and see this as well, and if not, that's okay. Okay. It's working. Wonderful. So most of us are in manufacturing, healthcare seems to be a big one, as this will tailor, right? So working in heat, especially in construction, it's quite different if you're in an indoor setting. If you work in healthcare, seeing these workers, manufacturing, I think is going to be huge. Yes. It seems like some majority of us are working in manufacturing, government is another. So policymakers, which is excellent because we need help right now, especially around how to regulate heat, impact of heat for workers around the world. I just had some really good opportunities this year to actually try every single continent except for Antarctica and speak about topics around not only heat, but any kind of work hazards that we're seeing. And we can see now it's changing quite a bit in the landscape of that, but it seems the majority of us are either manufacturing and healthcare, meaning we're probably offering some advice to near-site or on-site clinics. So we'll definitely build this into our talk today, gearing towards a lot of folks in industrial hygiene, working in manufacturing, and more of a seasoned workforce as well. Wonderful. So this one is actually going to use a little bit of AI. We're going to use the idea of synonyms that you can use. And as you type words in here, words that come to mind when you see or hear the word heat strain, what does it mean to you? What words do you connotate that with? Does that kind of share the experiences in a different way? And it seems like we're having a little hiccup here too, so I'm going to go ahead and move over here and then go back, and it should refresh hopefully the page, and then you should be able to start typing it in here because this will give us an idea of a word cloud that kind of generates thoughts around what we mean by heat, what does that impact mean to us overall? And it seems like we're having a little bit of a technical difficulties, but that's okay. We'll get through this and let's see if this restarts. If it doesn't, that's okay. We can definitely get through the talk without it. But as words come up and you have thoughts around this, I want to share some sort of common misperceptions around heat and what does it mean to different folks? How do we manage the idea of working in an environment that can be quite stressful for our employees? And in my part, I'll talk more about the physiologic response, the medical kind of lookouts that we need to have, the organ system that can affects, and how does that really change the way we kind of look at work, especially when it involves heat or other things as well. So it seems like this might not be working, but we'll go ahead and move forward. Eventually it should pop up in your browser. If it doesn't, then it's okay, we'll get through it, but I just want to go ahead and type it in and we'll come back to this at the end of the talk as well. So overall, understanding heat, the physiological response is going to be very important. What do we mean by it, first of all? How does it impact what we need to do? And what kind of organ system might it impact as well? So let's see if this is back online now. What kind of organ system do you think will be impacted by heat overall? Is it going to impact different body parts more than others, or are there opportunities for maybe some ideas of what's going on? It seems like our browser is probably not working, so let me see if I can reset this as well. It was working fine, so it must be something else going on, and it seems like it must be something in our system. So I'll go ahead and continue and say it's actually all. It's the brain, the heart, and the kidney. And I'll go through organ by organ and making sure that we understand and speak in a terminology that we can at least understand and hopefully be able to improve upon that as well. And then we'll save the questions and discussion towards the end, so feel free to continue to ask your questions in that modality, and after Dr. Murthy is done, we'll both have enough time to actually go through a conversation and talk about this as well. So let's talk about the impact of heat on the human bodies, and I talk about how it affects your neurological system, it impacts your cardiovascular system, as well as your renal system. And we're going to talk about some management around that and gear it towards some of our safety professional friends and industrial hygiene friends is, what do you do as a non-medical professional to be able to help impact this in this workplace and protect the workers as well? This is a great summary of the physiologic response. It really gives you an idea of what kind of impact heat can truly have on your body and how it could be multi-systematic and systemic in that it can really impact not only the brain, the heart, your kidneys, your vessels, but your body is really resilient in multiple ways as well, depending on how you hydrate yourself, how much fluid you're losing, and how much thermal strain is really impacting it. So I think this pictogram that came out of the study is actually a really good summary and depiction of what we need to do when we're involved with different kind of heat environment as well. And this is a summary of what I'm going to talk about over the next five minutes or so and how it really impacts each body organ. I just want to understand the why and the how, and that will help you understand just in general, I'm not going to teach medical school the eight years of training or so into like the next five, 10 minutes, but at least gives you an idea of how to impact the workplace by designing programs that you can recognize that when people have physiologic response to heat, you can recognize the symptoms and get medical professional help at that time. But in general, this is how it affects your body overall. So let's go through each of the organ systems and really figure out how this might impact them. How does it change what we need to do? The cognition, you know, how are you thinking? And especially if you know someone, is it impacted in the brain a different way? Are you definitely having coordination? Are you stumbling? Are you walking in a really strange way? You're starting to get a little dizzy or starting to have imbalance when you're walking, definitely does impact overall your response time. So if you're operating kind of heavy equipment, definitely do not want you doing that when you're starting to have these kind of systematic feeling around what that looks like when it's impacting your mind, your body, and especially what you're thinking and your process of coordination. And these are things you kind of see, these are symptoms that you kind of recognize. And even non-medical professionals should be able to see this. And I'll talk about what we can do in emergency responses. But dizziness, you know, is one of the most common systems you kind of start to see confusion and in worst case scenario seizures, which I've seen sometimes in the ER when they're coming in post a really severe heat stroke. And I think there's a lot of confusion there around how to manage that. And we'll talk about that when we go to the clinical management piece of it. So a lot of different damages to the body, right? Different damages to the neurons and how do you recover from such effects from it? It's sometimes a one-way street, but a lot of it is preventable. You know, you got to look at how heat stress can really impact the damage it does due to the elevated temperature. Our body is, again, it's quite resilient depending on where your reserves were beforehand. Talking about the oxidative stress that it might have on you as well. And then how do you recover from that? So let's go to the heart. The heart responds in very unique ways. Your heart rate definitely starts to increase when you start to have some sort of heat impact on your body. And luckily, a lot of us are wearing wearable devices now. We'll talk about that in the physiologic monitoring, but heart rate is one of those things where it's universal, right? We're all human. We have a heart that beats and it beats in a certain way that increases when you start to have different kind of flow. Sorry, let's turn off. Let's turn back on there. And it really talks about how does that flow impact your cooling mechanism, right? Your heart rates increase, your decreased blood flow to try to cool yourself quickly. But what does that mean to your overall stroke volume? Meaning how much volume is being pumped out in the heart is actually decreased now, right? Because if you think about it, when the heart rests and it gives you time, the blood starts to fill in the heart. But if you're pumping quickly because your heart rate's going up, you don't have a lot of that cardiac output now. Because of that, your brain's not going to get it and your body, the rest of your body is not going to get the blood either. And because of that, that's why you see all the systemic impact to it. So that's why heart rate is so important when people ask, well, what's the one thing you want to measure? I would say your heart rate because that will give you so many pictures of what it would look like and what's going on inside your body as well. So I think it's going to be really important to talk about dehydration as well. You know, what do we do when people don't have enough fluids in their body? Does it affect your blood pressure? Does it affect overall health? How do you monitor that? Right. And we'll go into that when we talk about some of the physiological monitoring to this as well. We'll talk about the severe cases, just like seizures. It causes those sodium imbalances and gate channels that kind of sends the voltaic images and electrical conductance in your brain, your heart, similarly. So you're going to be at risk of arrhythmias, right? So when you exacerbate some of these things that we talked about with a decrease in your stroke value, your cardiac output, it's going to really cause you to have heart go to really funky ways where it's perhaps not beating the right way it needs to be. Imagine if you already have a heart condition to begin with, you're already at a low reserve. So a little bit tip and the heat impact would definitely change it in a different way. And the last piece on organ I'm going to talk about among some of the others are the kidneys. Kidneys are really impacted when it has dehydration. It's a very resilient organ as well. But sometime when you leave it, it can really cause some acute kidney diseases and injuries that we see. We can measure this in the blood through a creatinine. We can actually look at through different modalities. But ultimately, this is one of those other organs that help maintain the homeostatic balance between what you need to do between what your heart does and pumping the blood and the kidneys maintaining that as well as keeping your hydration status. And one of those ways you can track how you know your dehydrated is looking to color the urine, for example, and this is why, because we know the kidney is one of those things that concentrate the water before it leaves your body and excreted that way. So the kidney is one of those important organs that we kind of don't want to forget about when it comes to that heat impact on the workers. So these are things I talked about, you know, your susceptibility really depends on your pre-existing conditions, if any. And sometimes you don't know, right, because some of these workers come in and have certain diseases that you don't know about, but they're sometimes not accommodated because they don't tell you. So you don't know whether an accommodation or need or not, but you'll know when it's out in a hazardous environment where the temperature starts to impact your physiologic and body responses to this. So I think it's really important to have a good, strong early detection for it. And long term, it can become more of a serious problem with the kidneys as well. So I think that's when I put one of those organs on there and really talk about why it's so important. So to gather all those three organs together and talk about symptoms now, and how do you classify that? So the easiest one you kind of see for medical professionals is a heat rash. Non-medical professionals, I know it's a little harder. People are like, what? That looks like a heat rash. I didn't know. But yes, that's usually one of the first signs you're starting to see that there is some sort of perspiration occurring and some blocks, sweat ducts can do this as well. Then you start developing some heat syncope, you're starting to feel faint about it. This is when your blood flow to your brain is starting to decrease, your heart rate is starting to pump quickly. So your overall sort of blood being pumped out is less. And then your brain is the one that senses the quickest and the most. And then your muscles start to have some issues as well, right? Lack of oxygen, like I said earlier, when the heart pumps so quickly, it doesn't have time to fill up the blood to pump it out to the body. So now you have less blood going out to your muscles and extremities. And that's when you start to have these symptoms there as well. Then you start looking at heat exhaustion and stroke, right? Those are more severe things, but definitely you need to start getting them into the emergency rooms or having an emergency response, track that and keep that accordingly. And using sweat is usually not the case anymore. And I'll show you an article we published just a couple of months ago around how to act hastily around this. And we can talk about doing a clinical management. But I want to share and spend some time around this topic. And luckily, this has been published through our ACOM Practice Guidelines. So you should be able to see that here. The citations will be in the chat. So you can see that click on the URL there and then you'll be able to pull this article up and take a look at it. And this gives you a really good idea for the non-medical professionals as well to design a program around how to prevent kind of heat related injuries that we see, especially in occupational settings. And it goes to and outlines a very well detailed thought around this that we kind of pulled a consensus around at ACOM overall. So I encourage you to go read this article and give those who are not working in this field or understanding a little bit of what we need to do to respond to some of these related injuries as well. So this is kind of overall kind of looking at how do you surveil for certain issues and understanding those pre-existing conditions that might occur for people who are working in these heat conditions. How do you send people back to return to work afterwards? We'll talk about physiologic monitoring over the next 20 minutes and then we'll talk about other measurements we can look at, maybe ask some questions along the lines during the Q&A sections. The next couple of slides was more designed for folks in the medical professions overall. So I saw we had some physicians and advanced practice providers as well that we can share. But I'm just going to go through it just briefly because I think it's a little bit too much for the non-medical professionals as well. But it gives you sort of an idea. And all this is outlined in the article that's posted in the chat right now. So you can click on it, take a look at it, read it. And this really gives you an idea of how do we impact the ideas of heat stroke, heat exhaustion? What do you do when you start developing heat cramps? What does it look like in terms of muscle spasm? How do you pass out? What happens when you faint? What does that mean and why does that occur? And then the heat rash that we talked about earlier as well, when it turns really red or if it gets a little itchy or if you're starting to get vessel, how do you recognize that as an early sign and send them to the medical professionals immediately? How do you deal with dehydration that we talked about? These are more sort of symptoms and things you need to look for, something that the emergency responders should at least get a clear understanding on earlier on. But for the safety professionals, industrial hygienists, I just want to let you know, this is sort of the medical conditions we're looking for when you put the lens of a health care professional on and looking at heat exhaustion and looking at avoiding kind of heat stroke scenarios as well. How do you look at laboratory work to understand when you're truly dehydrated or not? What are the signs and symptoms you can look for in those cases? All this is in the article. So it's summarized here for you. Like I said, this is more geared towards some of the the medical professionals who can be managing with some of the ideas of the heart, the brain and the kidneys specifically. I just want to call out, you know, we have workers out there right now that have unknown etiology, meaning they don't know why you have kidney disease. And this should be on a differential, meaning as a physician or a nurse practitioner or a PA in the US or a physician globally, you know, these things you want to ask if there's any kidney problems because they've been exposed to heat for so long. And this is when you start developing long term kidney disease as well. And it's quite prevalent. An article goes through how often that is. The key is this is all preventable, right? The key is how do you prevent this from happening where there's an engineering control you can put in administrative and ultimately some of the PPE, the hydration is going to be the key as well. So just remember, the hierarchy control is really important as we look at this and the timeliness of response that is going to be key. So this is one of those articles we publish and the Harvard School of Public Health is willing to share this. I'll show you the next slide. You can take a screenshot, but this one is more from the article and I'll share your citation of this in the chat right now. And thank you, Nikki, for doing that. So you can see that the link will take you to the article and talks about how do you respond to this? How do you design a protocol now? So we kind of give you an outline in this editorial and a great work of my residents back at Harvard and a shout out to Dr. Barry Juice. And I think he did a great job putting this together. He was willing to share this idea. What do you do when you respond to heat and heat stroke? Respond with haste. Look at the heat exposure. See what's going on in the individual. Are there any altered mental status? How do you start cooling them almost immediately and it's time to call 911? And it truly is an emergency and don't delay because it can truly impact a body in a very unique way. So feel free to take a shot of this if you have that. And you could also look at it through the article as well, through our journal, through ACOM, which is the Journal of Occupational Environmental Medicine. And here is the sort of brief outlook at that. And this was just published just last year. So you can take a look. It gives you a really good updates and prevalence. So you can use some of this data as you put your protocol together as well. But ultimately what it really means is that how do you recognize and see what heat stress can do to your body? And what's the role of our physicians and APP colleagues in responding to this? And how do you be vigilant, be informed that even though traditionally we always look at sweating and not sweating as a criteria, people who have exertional heat stress truly does have a very different way. So even if they're sweating, that doesn't mean they're dehydrated. So keep that in mind. I think that's really important as we look at that. And really this is preventable. So I think we're gonna come back to questions and discussions at the end. So please go ahead and type stuff in there. Unfortunately, this didn't work earlier, but I just wanted to go back and talk about what does it mean to have kind of heat stress and heat strain? And if you're able to see this now, you can feel free to put it in and I'll be happy to share it later on. But if not, I'm gonna pause here, turn it over, and we're gonna really focus on how to make recommendations around physiologic monitoring with Dr. Morsi. Over to you, Maggie. Awesome. Thank you so much for a wonderful presentation, Dr. Zaito. It really sets the stage for us to discuss physiological monitoring to assess heat strain. So I'm gonna share my screen and we will get started. Sorry, everybody. All right, hopefully everyone can see it okay. So I am, as I was introduced earlier, Maggie Morsi Basler, Assistant Professor of Health Sciences at Providence College, but also the Chair of the Thermal Stress Working Group at AHA and very honored to be part of this webinar with Dr. Zaito. And so what I'm gonna be talking about specifically is the physiological monitoring piece. And so the information that I'm gonna share is coming from a white paper that we just published. It's a AHA white paper. The QR code is attached and I feel very honored to be the Project Chair and lead the effort for this paper, but had a tremendous amount of wonderful collaborators. So I wanna share their names as well. And so what I'm gonna discuss today is a few different things, is really first starting with what's the purpose of physiological monitoring when we talk about assessing heat strain? What are the benefits? What are some challenges? And overall, what are some considerations? I think there's a lot of questions about what variables should be assessed and what are some limitations? And I hope to outline some of these and also hope to get some amazing questions following the presentation. And so before I start, I do wanna highlight the difference between heat stress and heat strain, which Dr. Zaito alluded to or started with in his presentation. And the reason I do is because I see the terminology used interchangeably, but really they're very different and they quantify different things. And so when we're talking about heat stress, we're really trying to quantify heat exposure. And so that would be the environmental heat exposure, metabolic heat production that the body produces as they perform work in the heat and also clothing that can increase heat exposure as well. And so to quantify heat exposure, we tend to use environmental monitoring. So a lot of times it uses the environmental data such as wet bulb, low temperature, heat index, and more, and uses adjustment factors for clothing and metabolic rate. But when we're talking about heat strain, that's when we utilize physiological monitoring. So what heat strain is telling us is how the worker is responding to that environment and really that level of heat exposure. And so there are many benefits of monitoring heat strain, especially with physiological monitoring is first, it tends to be a real time and continuous data that tends to go to a cloud-based system. It's very individualized. And in most cases, it tends to be very easy to wear. And so what the big benefit I would say that assessment of heat strain through physiological monitoring does is it addresses some pitfalls of environmental monitoring. And this is not to say that environmental monitoring is not a critical piece of a heat stress prevention plan. I think that physiological monitoring should always be utilized among many other prevention strategies. But what physiological monitoring can do is it really can account for that intra or inter variability that you see among different workers and how they respond to their environment. So some examples of some things that causes variability is sex, age, disease state. So many workers may have hypertension, diabetes, obesity. This changes their physiology and how they may not respond or respond differently to the same level of heat exposure as someone who doesn't have this particular disease state. And hydration status, heat acclimatization, medications are all ones as well. So again, some of the benefits of using physiological monitoring is accounting for that variability. And there are multiple different methods or reasons you can use physiological monitoring. And I say the first one that most people think about is use of it for risk assessment. So can I detect whether or not someone or really have an early detection of having a heat related illness? I do say that if you are utilizing it for this purpose, you have to be very, very careful because again, it sounds like most people on this call are not physicians or healthcare providers. So you shouldn't be using it for medical diagnosis. And if you're using it for risk assessment, you have to be very sure that the device you're using is measuring what it's intended to measure as well as has very strong validity. However, there are different uses of physiological monitoring that I think people often forget that can be really useful. So we can use it for decision-making. When do we need to alter a work environment? Or when do we need to change a policy and procedure? You can use it for assessment of interventions. Say you implement some sort of cooling technology. Is it reducing some of that physiological strain you were previously seeing? And lastly, and again, I think this one is probably the lowest hanging fruit is you can utilize these systems for health promotion and educational purposes, hopefully to facilitate behavioral change. And so it really like if you have a device that a worker's wearing and they're able to sort of check in with their own data or their own physiological responses, perhaps that educates them on when they need to do better at self-pacing or potentially take a rest. So I think there, I wanted to start with this because there's so much more that physiological monitoring can do beyond just risk assessment. And so I wanna talk about some variables to consider when evaluating heat strain. And the reason I chose these three and why in the white paper we chose these three is because these are the three variables that have the most scientific data to support them. I'm sure there's no surprise to anyone here that there's many, many different variables out there, but there's many that don't have strong evidence-based recommendations or validity to support how this variable can assess heat strain. So some of them that I'm gonna go into detail is core body temperature, heart rate, heart rate recovery, I'll more so focus on just heart rate and then physiological strain index or PSI. And so I wanna start with core body temperature because I think when we think about heat strain, this tends to be the primary variable that we focus on. And for good reason, right? Because all these physiological responses that we're seeing to heat strain are primarily driven by changes in core body temperature. So your core body temperature acts within such a narrow window that even a small deviation can cause a physiological response. And if it continues to rise, can be very detrimental. Another reason why it's chosen is because it's one of the two diagnostic criteria for exertional heat stroke. And so Dr. Saito had mentioned this briefly, but for exertional heat stroke, you have a core body temperature above 104, but it's not just core temperature alone. There's also central nervous system dysfunction that is associated with that. So again, when we're thinking about assessment of core body temperature, yes, it's a great variable to use, but you also can ignore signs and symptoms as well. That's why a lot of times when I'm working with different people who are implementing physiological monitoring systems, I tell them that although this can be really helpful having core temperature assessment, you also have to make sure that you are still assessing those signs and symptoms because those are extremely powerful. And so I just want to touch on briefly some proposed physiological monitoring guidelines for core body temperature. So this essentially gives you some information about some decision-making. So if someone's core temperature is at a certain threshold, when do I need to stop work? When do I need to make it a modification? And again, I'm from the United States, so a lot of these are focused United States. There are many others globally out there with different guidelines, but some examples include ACGIH that looks at measured estimated core temperature, increases more than one degree Celsius from a pre-job core temperature of 37.5. NIOSH uses a three temperature fixed threshold, so one being mild and then moderate and critical. And so based on these system thresholds, you would implement a different series of controls or stop work altogether. And lastly, the World Health Organization, their guideline is essentially core temperature should not exceed 38 degrees Celsius when performing. And so the goal of all of these proposed guidelines are for workers to not reach very high critical core temperatures that could potentially be associated with a heat-related illness. And so there's multiple different methods of assessment for core body temperature. One is the direct methods, which are the most valid considered gold standard. So in the field, that would be gastrointestinal pills or gastrointestinal telemetry, excuse me. And then rectal thermometry is another. Of course, these are not always feasible, very costly. So we direct or people tend to direct their attention to other methods, such as indirect measurements. And I have that in quotes for a reason. This would be your oral, oral as an ear or tympanic measurements. When we think about it from a rest perspective, there's, you know, could be a close agreement between the gold standard and these methods. But when we're talking about exercising the heat, these measurements tend to not be very valid. And I'll show you an example in the next slide. There also are estimated measures that are really taking off and as advancements in technology occur. And these are these wearable devices that utilize algorithms or machine learning and use other measures to estimate core body temperature. Again, I say this all, please do not use for medical diagnosis if you are not a healthcare provider, leave that to the healthcare professionals. And so the reason that I caution people from using the indirect methods such as oral or tympanic is because when someone is exercising the heat, there tends to be a very large disagreement between gold standard assessments and these measures. So an example of this is a study that I led back in 2021. We were at a road race and we had the opportunity to measure not only gold standard measurement because these people came into the medical tent with suspected exertional heat stroke, but we also at the same time measured their oral as an ear thermometry. And what we found was there was a really big difference in the gold standard versus those indirect measures, much higher as core temperature got higher. And what I found too is a lot of times when we're looking at some of the research out there, there tends to be very good agreement between different devices and a gold standard as a gold standard temperature is lower, but as you continue to get hotter and harder, hotter, excuse me, that agreement tends to fall apart. And so I am a strong advocate for doing your own research and really following the evidence-based data. And I'll talk a little bit about some strategies to think about what's the best physiological monitoring variable or a device for you without actually talking about devices, I should say. So for them, there's these estimated measurements. Many are curated algorithms. They use Kalman filters, regression and more. Some are machine learning. So they're able to estimate core temperature with a single or multiple variable input. Heart rate and skin temperature are two that are very often utilized. And so this type of estimation is starting to develop very well, but I do say take caution in some of the interpretation of the temperature readings and monitoring alerts as we are continuing to have that technology advance. So next variable is heart rate. So heart rate is a great variable as Dr. Saito had mentioned, because it does reflect physiological strain. It tends to not only really reflect strain earlier than core temperature, but it's been measured a lot of times in research. And so there's been a lot of research that has shown the strong validity between heart rate wearable devices and the gold standard. And so, and it's also great because it's associated with global temperature and core temperature. And some of the ways you can utilize heart rate is by looking at peak or max or average heart rate. Both of these can be useful depending on the context, but I'll touch on momentarily. It's very, very important to not just look at heart rate in a single moment. Heart rate is a very transient variable in nature. So you have to be able to look at it to stained heart rates or high heart rates. You really get a true picture of physiological strain. So similar to core body temperature, there's a few organizations that provide a heart rate recommendation. So ACGIH, they recommend a sustained heart rates that exceeds 180 beats per minute minus the individual's age and years. And this is of course for someone who has normal cardiac response. And then the World Health Organization has just a small recommendation of 110 beats per minute for an allowable maximum at low metabolic rates. So they don't really have a recommendation for higher metabolic rates. And again, ACGIH has sustained in their language for a reason. And so that's why I wanna mention some caution to some fixed heart rate thresholds because heart rate is, or peak heart rate I should say, is very transient. And there's a lot of different stimuli that can change heart rate. So if you having some sort of psychological distress, that's an example that can increase your heart rate and sometimes doesn't always reflect the physiological strain. So again, I think as like a method to think about is think about a sustained heart rate rather than just a short sort of burst in a peak heart rates. And again, there's many different variables that affect heart rate. Age, fitness, body comp are some examples of that. Last variable I wanna touch on is physiological strain index or PSI. And so what this does is it combines core body temperature and heart rate together into a easy to use scale. So here on the slide is an example of one that was created by Moran in 1998. And there's also been some revisions. So instead of having 180 beats per minute as a max, you can actually input your own heart rate max. And so this is what the scale looks like. So zero to 10, zero side of the scale is low to little heat strain, but the nine to 10 is very high heat strain. So again, pretty easy for people to understand when it's put on a scale. So there's many benefits to it. It's easy to calculate. And this particular PSI, cause I will say there's many different PSI out there. I'm just using the one that's by Moran as an example, because this particular scale has been studied in many different climates, hydration levels, sexes and ages. But however, there's some limitations. One being that it is scaled within a certain core temperature and heart rate limit. So it's a max of 39.5. So anyone who's experiencing a core temperature above that, it's difficult to have a true representation of that physiological strain. And also people that are physically fit have higher core temperature thresholds. And what that means is they're able to tolerate in most cases, higher core temperatures than someone else who is not as physically fit. And so again, this is just highlighting some limitations that you could come across with PSI as a variable. And as term of variables, I just wanna end with some emerging variables to assess heat strain. And I say that they're emerging because we, again, we don't have a lot of research to not only support the validity of the variable and measurement of it, but also the validity of the decision. So for example, at what energy expenditure is too high or things like that. So some examples be hydration, energy expenditure, blood pressure, sleep quality and quantity, heart rate variability. These are just some that you may have see soon as an assessment of heat strain. Next, I'm gonna talk about some limitations and I'm sure that some of these are no surprise to everybody, but I do wanna leave at least 10 minutes of questions. So I will go through and happy to address at the end, but cost is a huge limitation, especially because for wearable devices, everyone has to have their own devices. And not only is it cost of the device itself, but there's work that goes on to actually understand the data. So it's the data collection, the interpretation, the management of that data is costly. You need someone to be able to do that. Also user acceptance is another limitation. Many people don't want their data collected because they don't know where it's going. They don't know what it's being used for. They don't want it to be used to determine their employment status. So recommendation would be to use an opt-in, opt-out or sort of like an informed consent process. So people can choose to do it if they want to. And they know really where the data's going, what it's being used for. And really just overall making sure that there's no additional penalties if someone needs more rest because that physiological monitoring device or variable told them that they need to do that. Limitation again is data analysis, interpretation and management. So a lot of times people will get these devices, but they don't have people to actually interpret it and manage it. So this can be challenging if you have very small numbers of employees or it's a small company to be able to sort of utilize this team approach. And most importantly, I think it's really important to have someone who can interpret the data, who understands physiology in the context of heat and how it affects the body, right? So, and it sounds like everyone on this call has a somewhat of a background in physiology, which is great. And that there's also time because a lot of times you're assessing a case by case review of data. So for example, you're seeing one employee whose data is always showing that they're having this, their peak heart rate throughout an entire day. So you're going to have to spend time evaluating that data. Lastly, and sort of sometimes no pun intended, a hot topic is data privacy. So there's concerns about ownership of data, sharing data, who's using the data. So I would recommend if this is at all a concern to have some sort of privacy agreement in place or really consult legal or regulatory professionals. So we talked about a bunch of limitations, but I wanna end on a limitation, which is the physiological monitoring performance. So what I mean by that is the validation of the method. So assessment of core temperature, heart rate, et cetera, but also importance of the validation of the decision. So like essentially at what core temperature should this person do X? So I'm gonna just talk about the validation of method in today's webinar, but really what that means is is this variable measuring what it's intended to measure? So is it accurate? Because if it's not accurate, it could lead to these false positives or positive negatives that can be detrimental. And so the reason why validity is so important is because there's a lot of conditions, especially when we think about heat that affect the validity of an assessment. And so a hot human environment can affect not only potentially an algorithm output, but the performance of the device itself, activity changes that clothing, individual characteristics can all affect validity. And so this is just some things that I like to think about when I'm looking at a study that evaluates the validity or agreement between a gold standard and a variable coming from a device, an estimated measure, is like to see who are the participants, the work environment, is it actually in an occupational work setting? What is it saying? Is it actually valid? Because a lot of times there's data out there that's showing really great agreement. However, it's not in an occupational context. So it's someone who's working under very low metabolic rates or they're in an office job. And while in their context, that's really helpful, it doesn't really share what we're experiencing on the occupational side. So I say this all to really look at the evidence and focus on and really make these decisions based on looking at scientific research. So just quickly, I talked about variables, core temperature, heart rate, physiological strain index, the different multipurpose use and the importance of validity of method and limitations as well. So I'm happy to address some of these more in the questions, but I do just wanna throw up my email here and I think I left 10 minutes for questions. So we're in good shape hopefully. I will stop sharing my screen. Wonderful. So Nikki, how do you wanna handle questions? And while we're doing that, I just wanted to pull up my slide to show you the results actually did come through. So I thought it'd be interesting to show what we thought about in terms of thoughts around what heat strain means to us overall. So I thought this is nice to share. A lot of people thought about fatigue, confusion. We talked about the differences between heat exhaustion versus heat strokes. I think that answer a lot of those questions there. But the idea of fatigue is gonna be one of those things you need to watch for, right? It's like impairment or anything else we're taught to look for in a work setting around safety professionals or physicians or others. I think it's really nice to capture this kind of thought amongst our group here of 700 people or so. What does that look like in terms of heat strain? So I thought it'd be nice to share this with everybody since we're here. And so Nikki, do you wanna facilitate our Q&A? Yes, I'm happy to. Thank you for pulling up that slide. That is great. And I'm gonna go ahead and share my screen just so folks can see Q&A and whatnot. We do have a few questions that have come in. Our first question is what long-term adverse effects does persistent heat stress cause? That's a good question. I think, do you want me to take a stab at it first, Dr. Morrissey? Please, yes, go for it. Yeah. So we talked about this in one of the slides from the physiologic responses. I think that's really important to go back and understand, you know, what does it mean overall? But this one slide summarizes, I think, very well in that you can see that it's multisystemic, right? I'd like to look at it from brain, heart, and kidneys. They're top three organs that you need to really look at. And really, how do we understand overall? What does it mean for us to appropriately respond to that? And I think this slide here really tells it all. And this is the article, it's in the chat as well. You can click on it. It's luckily open source, so you should be able to see it. Like the systemic impact and the physiologic response to that, it's all here. So what happens to your heart? What happens in your brain? What happens to the rest of your metabolic system and your circulatory system? And long-term, that's when it starts to hit the kidney as well. So I'd encourage people to go back, look at this. If you want further details, the article goes into great details about that. But also, you can reach out to your local, friendly occupational environmental medicine physician. They're in the community to help service you and answer a lot of these questions for your workforce as well. Thank you. Our next question is, what is physiological change during heat stress? Physiological change. So if I'm understanding the question correctly, I think what a physiological strain, I would maybe change some of the question to physiological strain under heat stress. But that would be really any changes in some of those variables I had discussed. And from a heat strain perspective, we're gonna see a little bit higher core temperature, higher heart rate, higher PSI. So hopefully I addressed that person's question appropriately. And if not, I'm more than happy to expand. But it sounds like they were just wondering what the physiological change was referring to. Yes. Thank you. Our next question, considering Gulf countries' hot and humid climate conditions, what do you advise the best monitoring system like WBGT, HI, TWL would be in the best in implementation and to minimize the heat stress illness cases? I'm happy to start. Maggie, can you also tell them, can you also let them know what those acronyms mean just in case those of us on don't know what that means, like the wet bulb or temperature? Absolutely. Yeah, so it sounds like they're asking, they're specifically talking about environmental monitoring in this question. So it would be wet bulb, low temperature, it sounded like they had a question, heat index. So I would say those are the two variables that are most often utilized and most often have guidelines for activity modification in the occupational side of things. I will say that wet bulb, low temperature is considered the industry standard in this space. Although some people tend to find that it has some difficulties. AHA actually has an app, not to plug it, but they have an app that estimates wet bulb, low temperature and you can utilize different factors to get a better depiction of that. And if you have any questions about that, I'm more than happy to address it. Thank you. Yeah, so those who are in regulated countries too, where read your regulations because some of them actually addresses which environmental testing monitoring you can or cannot or recommend what you should or should not do. So take a look at that too because sometimes you don't have a choice if you're in certain jurisdictions. Sorry, Nikki, back to you. Yeah, we've had a few questions regarding around this topic. So is it my understanding or is it true that once you've experienced serious heat related illness, you become more susceptible for the reoccurrence? So what steps can we take to mitigate risk for these workers? Maybe I can take this one first. Yeah, please. It depends. I think it depends on where you are and what kind of severity you had in your first incident. Just like your body is like not a robot, right? Because every time you have an impact or an incident to happen, disease process, your body doesn't fully recover back to baseline, right? Unfortunately, sometime when you get really sick, your body kind of adapts in a very different way. If you learn that in COVID, for example, it's a very different respiratory response system, cardiovascular response system. So if you look at our ACOM practice guideline and refer to the return to work section, that goes into some details around like, what does it need to be, what condition should you be back to so that you can get back to work as well safely? And just in general idea, the return to work model is, basically you need to be back at baseline and safe to go back to that job duty. So I think it's really important to think your body can be quite resilient, but sometimes it doesn't go back to what it was before, depending on how much impact or damage you might have on the body. Good example, seizure, right? Unfortunately, one of those conditions where if you had a seizure once, you're likely to have seizure again in the future. And then depending on what damage has been done to the body, it can sometime be resilient and bounce back to where it was before, but hopefully just like our mental mindset, it could bounce forward to where it needs to be to condition yourself to that or decrease those chances again for it to not be bouncing back to where you were. Next question. Yeah, we had a few on this and we'll see if you're able to make the comment, but are you able to comment on medical grade designation for devices that are used or that you would ask for any wearables that are FDA approved or commercial off the shelf fitness wearables? Are you able to comment on that? Yeah, so just full disclosure again, even though I'm an attorney, I'm not an attorney today giving legal advice that please don't get me in trouble, but FDA has really strict guidelines over what they regulate, what they don't. So it really depends on what the intention of you're using that wearable device for. If it's for diagnosis, treatment, prevention, something that's medical in nature, then yes, we'd need that FDA clearance for that. So I'll leave it at that. I won't say in a negative sense of it, but hopefully people get the picture of what I'm saying. Do GLP-1 blockers increase the risk of heat related illnesses? Ooh, the hot topic button of the past couple of months, right, GLP-1s. What do we do in terms of the expenses side of things, the impact side of things, the reality that it actually helps, it helped a lot of people. So I guess I'm gonna give you a lawyer answer. It depends. And the second piece is we don't know yet. There are some studies early showing that there is an impact because it does have different regulatory changes in your metabolism. For those of you who've witnessed the results of some of the GLP-1s medications to potential weight reduction to the tune of 10, 20%, even 30% of your weight loss does change your metabolic system in a very unique way where heat sensitivity would change in your body. So from a physiologic response as humans, it could be a potential danger there, right, because now your sensitivity to cold or even to heat, just like any other changes in your body, needs to be acclimatized appropriately as well. You know, I think both of us didn't really go into acclimatization too much, but I think that's a really important concept. I encourage you to go back and read Dr. Morrissey's article. She's written a lot about this as well. So, you know, I definitely wanna go back and look at that because I think that's an important question that ties into the question I was posed as well. Great. Next question. Next question. What work restrictions do we follow for someone with heat illness? Any accommodations needed when going back to work? Yeah, I'll probably take this one as well since it's a work-related question. So I think it depends, right, because this is really individualized because people respond to heat very differently, like we talked about. Depending on what body, organ, system, and impact. Was it the brain, the heart, the kidneys? So it really depends on that situation. For those of you in the US, you know, I'd encourage you to have some sort of interactive dialogue if sort of required under the American Disabilities Amendment Act. So I think it's really important that we kind of discuss and see what that situation is. And it also depends on what job you're going back to, right? If you're in a position where you can go back to desk duties or any kind of light duty defined by some of the ideas of what that means, what you're doing, whether you're operating equipment, posing any kind of public safety or a safety-sensitive position if you're using DOT terms. So I think it really depends. It really, on a case-by-case basis, you need to look at that, put the lens of a return-to-work model on. What does it mean to be able to go back to that job? Look at a job description carefully. And this is where I encourage you to have discussion with your physician or your advanced practice providers to really go through and understand what kind of job this person's going back to and make sure you get medical clearance that's appropriate to that job they're going back to. Otherwise, accommodate when you can, right? These people still deserve to be able to work, have the opportunity to be able to be productive. So I think getting back to work one way or another, it's better than not, but do it in a very safe way, taking into account your relationship with your occupational and environmental medicine physician. All right, we have time for about two more questions. And we've had a lot of questions come in. So if we don't get a chance to get to your questions today, please share them with either myself, and I'm happy to pass them on to the faculty or reach out to them directly with their communications that they had. But for this one, can you talk more about gastro heat stress monitoring? Is it primarily used in research settings only? Yeah, I can take this question. So gastrointestinal pills tend to be utilized for research because in research scenarios, we're interested in looking at the direct methods of assessment of core temperature. It doesn't mean that it can't be utilized in a work non-research setting. It's just that the pills themselves are expensive. They are about $50 per pill, depending on the company that you utilize. And for that, you'd have to swallow the pill every day, and it can change based on your GI motility. So I think it becomes more difficult. However, in situations where someone may have recurrent heat illness, people have utilized it in that capacity if someone needs to have closely monitored core temperature, but in short, mostly utilized for research purposes. Sounds good. And for our final question, with so many people on stimulants, has there been a significant update in heat stress in the populations? Do you have any recommendations for companies? Hmm. That's a... Do you know, Dr. Morissette? I'm not familiar with the... So like stimulants, I'm guessing they're referring to like energy drinks and things like that. Oh, is that what they mean? I wasn't sure. I think, I think. Yeah, let's ask about that. Like do you have caffeinated drinks? Because that has become very popular in the US and globally, actually. Do you have any foresight on that? Yeah, so I think we don't have a lot of research about the physiological effects of like an energy drink per se and how it affects in an occupational setting. Caffeine really doesn't have a huge impact on thermoregulation unless it's high concentrations or people are, you know, having caffeinated drinks without, you know, having adequate fluid replacement like water. But in terms of stimulants that like energy drinks and perhaps this isn't the one, the thing that people are asking, there isn't a ton of research out there. Yeah. But, go ahead, Dr. Seiko. No, go ahead. Yeah, no, I just want to... Yes, I think overall it's the idea of cyclic AMP activation, right? Because that's what caffeine and most stimulants kind of do. So if you think about it for more of a cellular physiological response, you know, you would think that because of that, you know, they would have some sensitivities around that. But I agree in terms of clinical studies to show that, I don't think that has been done that I'm aware of, but PubMed search can probably give us some answers around that too. Exactly, yeah. Awesome. Well, thank you so much. I think that's all the time we have for questions. So as a reminder, if you have additional questions or we weren't able to get yours, please get those over to ACOM at educationinfo.acom.org or please pass those along to the faculty directly. We'd love to answer as many questions as we can. For the question of the hour, ACOM will be issuing CME credit for this. In order to do so, it is required that you have an ACOM username and password, which you should have have completed this process when you completed your registration. So you'll wanna visit the website above, education.acom.org, log in using that ACOM username and password. Once you are logged in, you'll see my courses and you should see this webinar titled and you'll wanna hit start. And then you will follow through the prompts, you'll complete the evaluation and then you'll be able to claim your CME. And then your transcript would be available under the transcript portion once all those steps are completed. I will send this out via email so you have those instructions as well. If you need any further assistance, please email educationinfoacom.org. Again, a huge thank you to you all. Thank you to our attendees for joining us today. We hope you found this session informative and engaging and very insightful. I'd like to also thank Dr. Morrissey and Dr. Saito for presenting today and taking time. Again, as a reminder, we kindly ask that you complete that evaluation, it is required. It should pop up after today's webinar. And if you have any other questions, let us know. Thank you all and have a great day. Thanks everyone, bye. Thank you everybody.

physiological monitoring

workplace health

heat strain

heat stress

core body temperature

heart rate

physiological strain index

data privacy

workplace safety

heat-related illnesses