Summary
Many fire fighters pass their fitness tests, train hard, and feel strong—yet heart attacks still happen to people who look perfectly healthy. In this episode of Listen Up L27, host Jen Pennington sits down with Dr. Marcie Hamrick of the Station 2 Clinic to unpack the gap between being “fit” and being “metabolically healthy.” Dr. Hamrick explains why most heart attacks come from small, unstable plaques rather than major blockages, how chronic inflammation—driven by shift work, disrupted sleep, smoke exposure, and diet—sets the stage for cardiac events, and why Zone 2 training may matter more for long-term heart health than high-intensity workouts alone. It’s a candid, practical conversation about what’s really happening inside the body, and what fire fighters can do about it.
Key Takeaways
- Fit doesn’t always mean metabolically healthy. High fitness levels (like VO2 max) are linked to longevity, but plaque buildup in the arteries can still develop even in highly active people.
- Small plaques cause most heart attacks. An estimated 70–80% of cardiac events come from smaller, unstable plaques—not the large blockages people typically picture.
- Inflammation, not cholesterol alone, is the root driver. Inflammation makes artery walls “sticky,” attracting cholesterol and destabilizing plaque. Sleep disruption, repeated stress surges, smoke and toxin exposure, and ultra-processed foods all add to the inflammatory load fire fighters carry.
- Zone 2 training is the missing piece. Moderate-intensity exercise (roughly 60–70% of max heart rate, where conversation is still possible) trains the body to use fat efficiently, improves insulin sensitivity, and lowers blood pressure and cholesterol — benefits high-intensity training alone doesn’t deliver.
- Consistency beats intensity. About 150 minutes of Zone 2 activity a week broken into short walks and combined with strength training and attention to sleep, stress, and nutrition builds a stronger foundation than hard workouts alone.
Transcription
[00:00:03] Dr. Marcie Hamrick: It’s actually the presence of inflammation that makes the walls of the arteries sticky, and for cholesterol to be attracted to the wall of the vessel and cause plaques to be there.
So cholesterol alone, although it is certainly predictive of risk, it’s really the underlying inflammation that is even at the root of the disease itself.
[00:00:31] Jen Pennington (Host): Hey, Seattle fire fighters, welcome back to Listen Up L27.
And today we’re going to be talking to Dr. Marcie Hamrick from Station 2 Clinic. And we’re going to be talking about why fit fire fighters can have heart attacks. Most fire fighters might say that they’re in pretty good shape. They train hard, they push themselves, they carry weight, climb stairs, and work under stress. So when we hear about a fire fighter having a heart attack, it doesn’t always make sense.
So today we’re going to dig into that question. Why can someone who looks fit still be at risk? So welcome, Dr. Hamrick.
[00:01:08] Dr. Marcie Hamrick: Hi, Jen. Thank you.
[00:01:10] Jen Pennington (Host): Let’s say a fire fighter is working out and they’re passing their fitness tests and they feel strong.
How is it possible that maybe they’re still at risk for a heart attack? What are we missing when we equate fit with healthy?
[00:01:25] Dr. Marcie Hamrick: Yeah. So fitness and heart disease are related, but they’re not quite the same thing.
So we know that fitness, like in the form of VO2 max, for instance, is strongly associated with lower mortality. The more fit people are, the longer they live in general.
But we also know that plaque that builds up in arteries that causes heart attacks and strokes can still develop even in these highly fit individuals. So studies have shown, looking at athletes, that these highly active people still have plaque in their arteries, sometimes even more calcified plaque than inactive people. It’s kind of an interesting paradox in cardiology — again, we know fitness improves survival, but it does not fully prevent the disease of plaque buildup. So someone can be operationally fit but metabolically unhealthy. And that’s the gap that we’re missing.
[00:02:32] Jen Pennington (Host): Something we were talking about prior was it’s not always a large plaque buildup in the arteries. It can be small plaque buildup that can lead to heart attacks. Can you talk a little bit about that?
[00:02:45] Dr. Marcie Hamrick: Yeah. It’s interesting because 70 to 80% of cardiac events actually happen from smaller plaques rather than the big ones.
I think historically we thought about it like a hose getting increasingly clogged over time, and then the flow of that hose getting less and less in a slow, incremental process over time.
What we know now is that sometimes even a small plaque in an artery where there is inflammation present, that plaque becomes what we call unstable, meaning that it’s at risk of creating an inflammatory event that leads to a heart attack.
So a lot of times people may have small plaques and they’re not having any symptoms because it’s a small plaque. They can exercise just fine and be very fit.
But because of the presence of inflammation, that plaque can become unstable and cause an event without any preceding symptoms.
[00:03:59] Jen Pennington (Host): You started to go down the road of metabolism and hidden risks.
So what does that mean in simple terms? Are there things like insulin resistance, and how does that connect to cardiovascular disease?
What are your thoughts on that?
[00:04:19] Dr. Marcie Hamrick: Yeah. So in simple terms, metabolic health is how well your body manages energy.
So things like blood sugar, cholesterol, how your body stores the fat that you take in through your diet. When it’s not working well, you start to see, like you said, insulin resistance. Your body isn’t as sensitive to the presence of insulin anymore. And then you start to develop pre-diabetes, which can progress to diabetes. You start to see higher levels of triglycerides, which are fats that circulate in our bloodstream and increase our risk.
Lower HDL, or “good” cholesterol, can also be a sign of poor metabolic health.
And then we can also see increased amounts of what’s called visceral fat — the fat that’s in our abdominal cavity.
And that is something that we are actually evaluating at the clinic using our InBody body composition machine. It gives a visceral fat score that can tell you how much fat you’re accumulating in your abdominal cavity. And that, medically speaking, is the most inflammatory, the most risky type of fat deposition for our health.
[00:05:46] Jen Pennington (Host): Wow, I didn’t realize that you had that kind of equipment there that can do that. That’s really interesting.
[00:05:53] Dr. Marcie Hamrick: It gives us another tool to help us evaluate someone like we’re talking about — who may look really healthy and fit and can exercise well, but maybe, underlying their lab work and their body composition, reveals higher visceral fat than we would expect just looking at them.
[00:06:17] Jen Pennington (Host): Let’s talk about inflammation a little bit. Chronic inflammation can increase your risk for heart attack.
So are there things about the job — for fire fighters, sleep disruption, stress exposures — that make inflammation worse?
[00:06:34] Dr. Marcie Hamrick: Absolutely.
So inflammation is now understood as sort of the key driver of heart disease. We used to think it was cholesterol. We thought of cholesterol as circulating in the bloodstream and accumulating on the walls of the arteries and causing heart disease that led to heart attacks and strokes.
But what we’re increasingly understanding is that it’s actually the presence of inflammation that makes the walls of the arteries sticky, and for cholesterol to be attracted to the wall of the vessel and cause plaques to be there.
So cholesterol alone, although it is certainly predictive of risk, it’s really the underlying inflammation that is even at the root of the disease itself.
And then, going to your question about fire fighters, I definitely think that the job increases inflammation in a variety of ways.
Sleep disruption is a strong inflammatory driver.
Repeated stress surges — when the bell hits and you have to go in the middle of the night, that’s a huge inflammatory hit.
Exposures to smoke, particulates, toxins — that’s inflammatory. Diet patterns, especially what we call ultra-processed foods, things that you could never make in your own kitchen, or you can’t pronounce the ingredients of — we know those things are inflammatory to our body and promote disease.
And then that visceral fat, which is associated with insulin resistance, is also inflammatory.
So I think it’s often the lifestyle stuff.
And then, on top of that, the acute stressor of the bell hitting, the adrenaline surging, the blood pressure increasing, the heart rate increasing — it’s those acute stressors on the chronic picture of underlying lifestyle and inflammation.
That combination, unfortunately, sets up the risk for events like heart attacks.
[00:08:56] Jen Pennington (Host): Wow, that’s a lot to think about. Something you said before was, you know, just go out for a 20-, 30-minute walk. I think we picture fire fighters training hard, doing high-intensity training, pushing their limits. But we’ve been having a conversation lately about something called Zone 2 training. Can you explain what that is?
[00:09:18] Dr. Marcie Hamrick: Yeah, this concept was actually brought to my attention by a preventive cardiologist that I know and work with.
She was explaining how fire fighters, typically, if they have an hour in their day to exercise, are going to exercise at, say, 150%, you know, heart rate 150 to 200, and really push themselves because of the pressure people feel to be fit enough for the job.
But the problem with that — although that kind of exercise does increase fitness — the kind of exercise that is best for heart health is actually the Zone 2, or moderate-intensity, exercise. It’s usually a heart rate in the 60 to 70% of your max range. So for a lot of people, that’s a heart rate of around 90 to 120, where you can still speak in complete sentences and have a conversation while you’re exercising.
That Zone 2 type of exercise — which most fire fighters probably don’t even think of as exercise — is what trains your mitochondria, your body’s energy engine, the part of your cells that use fat efficiently. It improves insulin sensitivity, it lowers your blood pressure, and it actually improves your cholesterol. When you’re exercising intensely, in that anaerobic threshold of exercise, your blood pressure is really high, and it’s actually exerting some stress on the walls of the blood vessels.
And it’s not burning fat — it’s just burning your sugar stores.
So it doesn’t help lower your cholesterol or your triglycerides the way Zone 2 training does.
So it’s that moderate, steady-state work, when done regularly, that can make a big difference in heart health.
[00:11:25] Jen Pennington (Host): So let me ask — there are certainly going to be people who really like the high-intensity part of it. What’s the perfect balance, do you think?
[00:11:38] Dr. Marcie Hamrick: Yeah, I don’t want to dismiss high-intensity training. It’s excellent for building performance. It builds VO2 max, the ability to handle extreme demands like fire fighters have.
Again, we know VO2 max is strongly correlated with longevity, so it is important.
However, I think of Zone 2, or moderate-intensity work, as being sort of the foundation — important for heart health and cancer-risk reduction. And then the high-intensity fitness work sits on top of that. But sometimes people don’t have the foundation of the house — they’re just doing the high-intensity work without that foundation, which can lead to the situation we’re talking about, where people are super fit but maybe not metabolically healthy underneath because of a lack of moderate-intensity activity.
In terms of how much — I think of doing Zone 2 training for about 150 minutes a week. So 30 minutes, five times a week, would satisfy that. And it doesn’t even need to be 30 minutes straight. Studies have shown that walking several blocks, or doing five minutes here and ten minutes there, that cumulative time — especially time not sitting — matters. There are interesting studies on the risks of prolonged sitting; it’s about as dangerous to your heart health as smoking.
So even if you’re sitting and watching TV, or waiting for the next call at work, getting up and walking around for a few minutes has a significant impact on your risk of having a heart attack, even though it feels like nothing to a fire fighter.
[00:13:43] Jen Pennington (Host): Wow.
[00:13:45] Dr. Marcie Hamrick: Yeah.
[00:13:45] Jen Pennington (Host): I mean, that’s incredible. We’ve been talking about walking, but what about weights — working with weights, things like that?
[00:13:52] Dr. Marcie Hamrick: Yeah, I think a good weekly plan can look like lots of different things, but something like five days a week of 30 minutes of moderate-intensity Zone 2 work, maybe two days a week of higher-intensity training for fitness, and then one to two days a week of strength training.
I do think fire fighters often like building strength more than they like doing cardio — just from the majority of people I talk to. And I think we need to flip that a little bit and emphasize how important cardio is, not only for heart health, but for mental health, sleep, and cancer risk — and still do a good strength-training workout a couple of times a week, while making sure you get that solid foundation of moderate-intensity work more often.
[00:14:49] Jen Pennington (Host): So let’s talk about the biggest things a fire fighter should pay attention to beyond working out.
What are some early warning signs or indicators they shouldn’t ignore? And what’s the role of, say, their annual physical in catching these risks early?
[00:15:10] Dr. Marcie Hamrick: Yeah, so I definitely think about metabolic health — your blood pressure, your cholesterol, your blood sugar, your hemoglobin A1c, which is the diabetes screening test we do as part of the exam.
I also think about the things that drive inflammation, since we know that’s really important and at the root of heart disease. So: sleep quality and amount, stress management, nutrition, and minimizing exposures. And then also thinking about how you’re training, like we discussed — not just intensity, but consistency and balance.
[00:15:51] Jen Pennington (Host): I think that’s the big takeaway here, right? Fitness is obviously important, but it’s not the full picture. It’s about understanding what’s happening inside your body. We’ve talked about metabolism and inflammation, and how you can train and make a difference over the course of your career. Dr. Hamrick, thank you so much for being here. It’s always a pleasure.
[00:16:11] Dr. Marcie Hamrick: Thank you so much, Jen, for having me.
[00:16:15] Jen Pennington (Host): Thanks for joining us. Listen Up L27 is a Seattle Fire Fighters HealthCare Trust production. This podcast is produced by the Rhizome Collaborative. I’m your host, Jen Pennington. And until next time, stay safe and stay healthy.
