Maggie McKay (Host): We hear a lot about heart health, but what are the new trends in prevention? Exercise, for starters. Today, we'll talk with leading cardiologist, Dr. Michael Sills, to find out more.

Welcome to HeartSpeak, the podcast from Baylor Scott & White and Vascular Hospital, Dallas Fort Worth and Waxahachie, joint ownership with physicians. I'm your host, Maggie MacKay. Joining me today is Dr. Michael Sills, cardiologist on the medical staff of Baylor Scott & White Heart and Vascular Hospital, Dallas and Baylor University Medical Center, to talk with us about the importance of keeping a heart-healthy lifestyle.

Dr. Sills has a series of HeartSpeak podcasts on how we approach heart-healthy eating to maintain a heart-healthy lifestyle. The first in the series is titled New Trends in Preventive Heart Health. The second podcast in the series focused on food, The Latest in Eating Trends and Nutritional Insight from a Cardiologist's Perspective. The third in the series with Dr. Sills will focus on how exercise impacts the heart. We'll talk about the basics of the anatomy and the importance of keeping blood flowing. In addition, Dr. Sills, you'll touch on the importance of taking steps to reduce our stress levels. All of this information should help us lower our risk for heart disease.

Welcome, Dr. Sills. We're so happy to have you back. Would you please introduce yourself?

Dr Michael Sills: Thank you, Maggie. Delighted to. I'm Michael Sills. I'm a cardiologist at Baylor University Medical Center and the Heart Hospital with a specific interest in prevention. We spend a lot of time treating the manifestations of heart disease. One of the things that interests me is trying to help people find ways to avoid becoming one of our patients.

Host: We've heard that exercise is important for our heart's health. But from a physiological standpoint, help us understand the true why behind this.

Dr Michael Sills: So, it's very interesting. It's been a relatively recent observation that exercise makes a difference. And it starts back in the 1950s when, in England, a couple of public companies noticed that as they were getting their patients involved in the public health service, the English healthcare system, that they noticed some discrepancies.

First, the bus company noted that the bus drivers were much more likely to have a heart attack than the conductors. And they realized that those double-decker buses gave the conductors a whole lot of exercise every day. And for the first time, someone asked, maybe exercise matters. So, they did a comparable study for the post office and found that the phone operators were three to four times more likely to have a heart problem than the postman who is active. And all of a sudden, It became clear that a sedentary lifestyle carried a markedly increased risk of developing coronary artery disease and congestive heart failure. And, alternatively, being active significantly reduced the risk of coronary artery disease. But the question that then came up, and what we'll try and talk about today, is how much exercise is good for you, and try to dispel the notion or maybe necessarily clarify, is too much exercise a bad thing for you?

Host: Wow. What does the American Heart Association and the ACC say? What are their recommendations on exercise?

Dr Michael Sills: Well, it gets a little confusing, and some of this is because of context. People exercise for one of three reasons. They're either trying to maintain health and fitness, they're trying to rehabilitate from an injury or an illness, or they're trying to train for an event. And I think it gets a little confusing to look at all three of those scenarios and try to extrapolate what the ideal amount is.

The 2008 Physical Activities Guideline Committee report suggested 150 minutes per week of moderate intensity, or 75 minutes per week of vigorous intensity. But it also is helpful to try and understand what is moderate, what is vigorous. And so, what's been very helpful is something called METs, or metabolic equivalents. And that helps you understand what is considered moderate, what is considered vigorous. And then, you could even intensify it a little bit further to look at MET-hours per week, which helps you understand not only just the minutes, but also the intensity of that and how it affects your cardiovascular benefits.

Host: What about if you want to start small? Is that a good way to go? Because you were saying there is such a thing as exercising too much. But just getting started, what are your tips for that?

Dr Michael Sills: A few things. I think, first of all, you have to try to decide what am I trying to accomplish? Am I trying to improve my 5k time or am I simply trying to reduce my risk of developing coronary artery disease? There was a really great study that was done here in Dallas, the Cooper Clinic, where they looked at people who are just walking to see what kind of benefits that conferred over a longer period of time. It's over 15,000 people, over a five-year period, and what they found was walking, even relatively small amounts of walking and not sitting, had up to a four to five time reduction in the risk of what we call major adverse cardiac events. So, starting small, walking, even for brief periods of time, confers significant benefit.

The converse is that when you look at people who are runners, 25% of runners will report an injury that limits their exertion for more than one day over a three-month period. So, there's pretty clear evidence that, while you may get more cardiovascular benefit from running, you get a lot of benefit from walking and a lot less likelihood of injuries.

Host: Do you remember Jim Fixx who wrote the book on running, and then didn't he die of a heart attack?

Dr Michael Sills: So, I've actually had the privilege of talking to Ken Cooper about Jim Fixx, because I was always fascinated. So, the story with Jim Fixx was at a relatively young age, he was diagnosed with severe coronary artery disease and Fixx was stubborn. And up until that point, if you had coronary disease, you were told basically, "Sit still, don't do anything." and Fixx said, "I don't think that makes sense to me. I'm going to start exercising and prove that I can feel better with exercise and maybe reduce my long-term risk." And actually, Fixx was one of the first people to point out that you can have medical issues, coronary disease, and exercise. The problem is Ken Cooper has told me that Fixx probably developed more coronary artery disease symptoms, what we call angina, and actually died while running because he was too stubborn to admit that he really needed something done. But Fixx really proved that you can prolong the interval for need for a bypass, or these days a stent, by exercising, and that it's safe. But you have to, at the same time, be cognizant that when people get more symptomatic they need to get something done. But Fixx is a real trailblazer for us.

Host: And what about sedentary lifestyle? Well, obviously that's not good, but is that equivalent to smoking?

Dr Michael Sills: It's just about as bad. It's interesting. If you look, for example, standing more than two hours a day is associated with a 10% risk of all-cause mortality. There was a neat Australian study that looked at people over the age of 45. And if you just look at how much they walk versus stand, there was remarkable reductions in cardiovascular mortality just from not sitting. We are not meant to sit, and sitting is really bad for us. So, that's why your Apple Watch will remind you periodically, "Stop sitting, get up and move around." And even just five minutes of moving can really reduce that risk of adverse cardiac events.

Host: Okay. Now, maybe this is obvious, but I don't know, is it possible to reverse-- let's say you've been sedentary for years and then you turn 30 and you say, "I'm going to start exercising." Can you reverse damage done, previously?

Dr Michael Sills: That's a really good question. We don't really know the answer. We know, for example, that you can look at calcium scores, the amount of calcified plaque you have in your coronary arteries, and we can actually measure that with a calcium score. What that reflects is the total amount of plaque you have throughout your heart. The greater the amount of plaque, the greater the likelihood that you're going to have a heart attack.

What gets a little confusing is if you take a statin, or you get onto an exercise program, it'll increase the coronary artery calcium score, which is a little bit concerning or confusing too, because wait, that means if I'm taking medicine that's supposed to lower my cholesterol or I'm really exercising, the calcium score goes up. But what it reflects is the fact that you may not reverse the plaque, but what you do is you stabilize it. In other words, it's the non-calcified plaque that's most likely to rupture and cause a heart attack. So if you look at a couple things, if you look at distance runners or cross-country skiers, they tend to have a higher than normal expected calcium score, but they have a much lower incidence of heart attacks.

And if you look at the calcium score, for example, in patients who are exercisers, for example, of the mild to moderate risk calcium score, 1 to 399, those who have no exercise are four times more likely in that same group to have an acute cardiac event than those who don't. So, it may be that you can't necessarily reverse it with exercise. But clearly, you can stabilize what might be an unstable plaque and reduce your risk of having a heart attack, which is in the end, the most important thing that we're trying to do, is prevent adverse cardiac events.

Host: So, I know they always say, "Check with your doctor first before you start anything." So, does that apply here too, before you start an exercise program?

Dr Michael Sills: Yeah. I think that you have to think about how aggressively you're going to exercise. I think if you're talking about a walking program, there's no need to necessarily talk to your doctor before you do that. Certainly, somebody who's had a heart attack, somebody who's known coronary disease, a genetic predisposition to heart arrhythmias, for example; somebody who's basically under the care of a cardiologist, yes, absolutely should discuss what the safest way to proceed.

But the good news is exercise is so safe, especially walking. If you look at, for example, the risk of having a heart attack or a cardiac event, we know that in cardiac rehab, for example, looking at people who've had heart attacks, the risk is about 1 per 200,000 of a serious cardiac event in people who start exercising. So, it's extraordinarily rare. For the average healthy person, starting a walking program, no problem. But again, if somebody has had a known cardiac issue, or is under the care of a cardiologist, it would be appropriate to check. The one exception to that is somebody who is sedentary. And decides they want to go climb Mount Everest, or wants to do backcountry skiing and has never done that before. I think for somebody who's going to go to an extreme, I think then, yes, we would consider doing a stress test, calcium score, or something, just to make sure that they're going to be okay. But, for the average person doing reasonable exercise, walking is fine and safe.

Host: Are there benefits to walking or exercise in general when it comes to lowering your blood pressure?

Dr Michael Sills: Again, Cooper did a really interesting study about that. They sent out a flyer to the North Dallas Administrative Assistance Group and said, "We will give you a free pair of sneakers and a membership to the Cooper Center," where they have a beautiful track, "if at the end of your workday, you come and walk on our track for 30 minutes."

Now, you can imagine that there was a lot of chatting and gossiping and conversation that occurred. But what was fascinating is they did walk, maybe not fast, but they walked. And at the end of the trial period, most of the patient's blood pressures had dropped up to 10%. And this is not a lot of exercise. This was simply just getting up out of a chair and walking. So, we know that even relatively small amounts of exercise, five to 10 minutes of exercise at a time, maybe done multiple periods of time during the day, has clear benefits in lowering blood pressure, lowering cholesterol, and also some of the interesting things is lowering some inflammatory markers, which are also predictors of heart attacks.

So clearly, even relatively small amounts of exercise will do. For example, people seem to think that unless you're wearing very fashionable athletic garb, that you can't go out and walk. I've encouraged people, "Look at your lunch hour. Instead of sitting at your desk eating. even if you have to return calls, just get up and walk for 15, 20 minutes. You can return your calls as you do if you want." But just that little bit of getting up out of a chair and walking has tremendous health benefits.

Host: Dr. Sills, I don't know about you, but I'm a big advocate of walking with somebody. Because, number one, it goes by much faster and, number two, you always learn something and it's just more fun. If you can find a partner to walk with, do you think that helps?

Dr Michael Sills: It does, it motivates you. I think knowing that your partner expects you to be out there even though you may be a little tired, maybe a little cold. I think it's a real motivating factor to know that somebody else is expecting you to get out there. So, that's why running clubs are so effective in helping people train. It's just being part of a group and feeling like there's an expectation to get out there because there are lots of mornings people feel like, "I've got better things to do. It's too cold. I'm in a rush. But if you know that partner's going to be out there, you'll go.

Host: We touched on this a little bit, but I think it's worth repeating. Don't start out too crazy because then you'll be prone to injury, right? You don't want to go all out when you first start exercising again, whether you have issues with your heart or not.

Dr Michael Sills: Exactly. And I think, especially if you've got any kind of joint instability or muscle tightness, you've got to learn how to stretch, got to learn the messages your body is sending you about what is and what isn't safe. So, I think starting off slow is really important. We do talk about MET-hours and how much energy you're expending over a period of time. But really, you get a lot of benefit from relatively small amounts of exercise. So, starting slow, rather than not starting at all, is incredibly important.

Host: Dr. Sills, I don't know which is right because I've heard both, so maybe you can shed some light on stretching. You mentioned stretching. Do you do it before you work out or after or both?

Dr Michael Sills: Both. Stretching before helps you avoid overly tight muscles, ligaments, tendons. You can't do much for your ligaments and tendons. But certainly, you can loosen up your muscles. And what loosening up really translates is you increase the blood flow to your muscles, which helps get them more energy efficient, and it also tends to prevent overly tight muscles from being excessively stretched and tear. So, that's really an important way to avoid injuries.

Cooling down or stretching after is also really important for a number of reasons. Number one is you've got all this blood flow going to your muscles. If you cool down and stretch a little bit, it helps gradually reduce the blood flow. And for example, the biggest risk of cardiac rhythm issues or heart attacks occurs in the period immediately after exercise. Because what happens is people still have all this blood flow going to their muscles, diverting blood flow from their core, all of a sudden they stop and all that muscle activity, which is supporting your blood returning to your heart and keeping your blood pressure up, stops. Blood pressure falls, and it increases the risk of cardiac events. So, it's really important to cool down and stretch to let your muscles go back to their normal resting state.

Host: Makes sense. What about a heart rate when it comes to exercise and prevention?

Dr Michael Sills: There's a lot of confusion as to, what to do about heart rate. So, it depends on what you're trying to accomplish. Sort of the easy rule of thumb is if you take 220 and then, multiply that minus your age times 70%. So if you're, say, 60 years old, 220 minus 60 is 160. Most people would say train at around 70-80% of that, and that's where you will get ideal benefits.

If, however, you're trying to improve yourself, if you're training for an event, you may want to go up closer to 90%. What we're looking at is your ability to efficiently use oxygen and blood sugar, although it's not as accurate as physiologic stress testing. Kind of the rule of thumb is that 220 minus your age is about the limit that you should safely put yourself before your body becomes less efficient. So, that's, as a general rule, if you're just trying to maintain fitness, exercise between 70 and 80%.

Again, if you're trying to rehab after a heart attack or an injury, you may not want to push that hard. In fact, we recommend not to. if you're trying to bump up what we call your anaerobic threshold, you may want to push it a little bit more. But like I said, 70-80% of 220 minus age is about where you ought to keep your heart rate when you're exercising.

Host: That's good to know. So much useful information. I love this conversation, Dr. Sills. I think I'm probably one of the only people who does not have a smartwatch or a wrist device, but I know they're probably helpful. How do you feel about them?

Dr Michael Sills: You know, it's kind of like getting a program to balance your checkbook on the computer. It's really not any better than it was with a pencil and paper. And you have to buy a computer. Now, if you want to buy the computer, great! And I think it's the same thing with the smartwatch. I think they can be useful if you're not able to monitor your own heart rate.

I think, for example, the Garmin watches and the new Apple watches tell you all sorts of interesting statistics about your level of fitness and your heart rate. But in the end, most people, for most reasons, don't need all that information. You really just want to know, am I pushing myself? Am I getting my heart rate up where it ought to be?

 I think good rule of thumb is if you're walking or running and you can't sing out loud, then you're probably going too fast. And in which case, if your heart rates a little faster than it ought to be or you're feeling like you're a little more short of breath, slow down. You're better off with duration than intensity. So while the smart watches can give you tremendous amounts of information, most of that's only relevant if you're trying to improve your performance as opposed to just staying fit.

Host: I mean, I guess it is more beneficial to walk more times a day. But let's say you walk once, three miles at one time, or is it better to walk three times a day, one mile each?

Dr Michael Sills: It depends on what you're trying to accomplish. For example, if you're trying to burn fat, it actually takes a while for our body to change over from burning sugar that's in your blood, stored sugar near your muscles, and then breaking down fat. So if you're going to break down fat, you have to be active for at least 20 to 30 minutes. If on the other hand, you're trying to achieve all the other benefits of lowering blood pressure, cholesterol, inflammatory markers, strengthening joints, avoiding osteoporosis, that's actually more about activity. So for example, if somebody walks that same 30 minutes, but five times a day, you're going to cheese all that benefit. You may not burn as much fat, but again, if you're simply trying to get a level of fitness and health, it's fine whether you want to do short bouts or longer bouts.

Host: Good to know. Just get out there and do something. What do you tell your patients, Dr. Seals, in general? We're going to talk more about stress and exercise. But in general on this topic, what do you tell your patients?

Dr Michael Sills: That sedentary lifestyle really now is considered one of the major risk factors for coronary disease. Like you alluded to earlier, it may be as deleterious to your health as smoking. So that we're pretty engaged in talking to people. "Do you have high blood pressure, high cholesterol, diabetes? Do you smoke? Do you have a family history? And tell me about how much exercise you do. Tell me about how much activity you do." If you're sitting for more than two hours a day, that's a significant risk factor for the development of high blood pressure, coronary disease, congestive heart failure, kidney disease. All of those are really made worse by a sedentary lifestyle.

So, the whole idea is to give people a reason to be active. But then, it's not about that svelt, great-looking marathoner, that's almost intimidating to people. Well, if I don't have this great clothing and I don't have these expensive shoes, am I still going to get any benefit? The answer is absolutely. You can wear regular shoes. You don't have to have any kind of athletic garb and you don't even have to sweat. It's just simply a matter of getting up, not sitting, and getting active at any level. Once people cross that threshold and they feel like they can walk, then you start talking about, "Let's talk about your goals of what you want to accomplish. Do you want to get more fit? Do you want to lose weight? Do you want to lower your blood pressure? Do you want to lower your blood sugar? Let's then talk." But the first step is just getting people out of the chair and moving.

Host: Dr. Sills, we've heard that exercise can help people reduce stress. And I've also read that there's research that's proven prolonged stress is harmful to our hearts. Can you tell us more about that?

Dr Michael Sills: There's a couple of things we've looked at to try and address what we know by observation, that people who exercise tend to sleep better, have less stress. What does that mean?

So, they've looked at adrenaline levels and inflammatory markers. We all exist with a certain amount of adrenaline in our blood. That's what our body uses to help keep our blood pressure where it is, get our heart rate where it needs to be, and lots of other bodily functions. We also have hormones in our body that slow everything down. And we exist in a balance. If you are chronically stressed or sleep-deprived or don't exercise, your adrenaline level tends to be higher. People tend to have a higher resting heart rate. They tend to have a more interrupted sleep. They tend to have higher blood sugars, higher blood pressure. We know that chronic stress is debilitating, but these are actual manifestations. in looking at some of those studies where they've asked people just to do really minimal exercise and looking at adrenaline levels, it turns out adrenaline levels drop with exercise. To make a direct correlation between heart attacks and serious arrhythmias is a little harder. But most of us feel that by dropping your adrenaline levels through exercise, it will absolutely have a positive effect.

The other interesting thing is we know that plaques, which are stable, tend not to rupture and cause heart attacks, but there are times that plaques destabilize. And when they do, they tend to rupture, blood clots occur, and you get a heart attack. And what's really interesting is we can measure inflammatory markers, things that tend to cause plaque rupture. We know that there's certain foods, ultraprocessed foods tend to increase inflammatory markers. Smoking increases inflammatory markers. But in a really interesting way, exercise reduces Inflammatory markers, things that you can actually measure, which we think has a very positive effect on the risk of heart attacks.

Host: What are some of the foods to avoid that you say, spike inflammation?

Dr Michael Sills: We know that ultraprocessed foods are really deleterious to our health, and that is food that has been modified in a way to make it more palatable. And we know that, for example, overly salted foods, overly sugared foods, foods that are heavily involved with monounsaturated fats. We know those are all bad for you. We know from looking at blue spots. We know from looking at areas in the world where Mediterranean-type lifestyles occur, that these people have a much lower incidence of coronary heart disease and cardiac events. So, there's pretty clear evidence that eating a more Mediterranean-style diet, which is very little in the way of animal protein, mostly unprocessed raw vegetables, Fruits, nuts, is clearly of benefit when you look at cardiovascular health. So, that's good diet to emulate. But blue spots, as we've talked about before, are fascinating. These people live longer, they have fewer cardiac events, and they just seem to have an overall better health than people who eat more of the ultra-processed diets.

Host: Well, we have covered so much useful information in this third of the series of the three podcasts on our heart-healthy lifestyles. Dr. Sills, thank you so much. I always look forward to talking to you because I learn so much. And we look forward to having you back. I hope we get to do another one soon.

Dr Michael Sills: we're going to talk more about inflammation and the biochemistry of just what you're talking about. What is behind ultra-processed foods, what is behind the Mediterranean lifestyle that seems to so positively affect things. So, that'll be coming next.

Host: Oh, that's awesome. I can't wait for that. Thank you again.

Dr Michael Sills: My pleasure, Maggie. Thank you for talking with me.

Host: That's Dr. Michael Sills, a cardiologist on the medical staff of Baylor Scott & White Heart and Vascular Hospital, Dallas and Baylor University Medical Center. To find a cardiologist, please call 1-844-600-2342. That's 1-844-600-2342 or visit bswhealth.com/heartdfw.

Thanks for listening to HeartSpeak, the podcast from Baylor Scott & White Heart and Vascular Hospital in Dallas, Fort Worth and Waxahachie. I'm Maggie McKay. If you found this podcast helpful, please share it on your social channels and be sure to check out our entire podcast library for topics of interest to you. Baylor Scott & White Heart and Vascular Hospital, Dallas Fort Worth and Waxahachie, joint ownership with physicians.