Tag Archive for: cardiovascular disease

Yes, Intensity Matters

/in /by

Can you get away with less time exercising and still protect your cardiovascular system? We know from Tuesday’s Memo that more time spent on physical activity will provide more protection. Can we save some time? Or perhaps better stated, can we do something in short bursts of time that can increase the moderate to intense exercise we get?

Before I answer that, remember that physical activity means everything you do that requires movement: walking to the kitchen, gardening, cooking, and the activity involved in your job. Exercise is also a part of your overall physical activity. In the study, all activity was registered by the accelerometer the subjects wore.

Intensity Matters to Reduce CVD Risk

With that in mind, the answer is yes: exercise intensity matters when it comes to protecting yourself from cardiovascular disease (CVD). I must admit that the charts and graphs published in the study were challenging to understand. They used a percentage of calories used per day as the way to measure outcomes. For the exercise intensity analysis, they considered the percentage of calories at moderate to high intensity. They found that as the percentage of activity at moderate to high intensity increased, the rate of CVD events decreased.

Here’s an example. Let’s take a 180-pound guy who uses a low amount of energy in physical activity such as five calories per kg body weight. The total calories he uses daily would be about 400 calories, including any exercise he did. But let’s say the percentage of moderate to severe intensity exercise rises from 10% of total exercise to 20% of that total. His risk of a CVD event would be reduced from 2% lower to 20% lower. He hasn’t invested any more time, yet he gets a jump in benefit just from increased intensity.

What Does That Mean for You?

Does this mean that everyone should be doing high-intensity interval training? Not in the classic sense; what’s high intensity for you may be impossible for your elderly neighbor and a breeze for your kid’s soccer coach. You don’t have to do special workouts such as high-intensity interval training where you’re going to bust a gut for 60 seconds and then take it easy for five minutes. That is intense, but it takes less time overall and you could do that if you want; there’s more info at drchet.com if you decide to try it.

In physical activity, everything counts from housework to walking the dog to breaking into a run to catch a bus. Those would show up as mild or moderate intensity, or high-intensity exercise for the running. It doesn’t mean that all the exercise you do has to be high intensity, but investing time in higher intensity exercise may provide you with additional benefits. Working a little harder is going to reduce your risk of cardiovascular disease and, while not assessed in this study, your risk of type 2 diabetes, hypertension, and cancer would be reduced as well.

Of course, the question is what’s high intensity for you. The chart above is geared toward weightlifting, but it will give you some ways to think about how hard you’re exercising, no matter what you’re doing. If you’re running for the bus, could you run one more block? If you’re cleaning house, do you have enough juice left to go for a bike ride?

The Bottom Line

You must be fit enough and ambulatory enough to actually do moderate to high-intensity exercise. But you know something? I know of one physical therapist who encourages patients to do jumping jacks while sitting in a wheelchair. Of course they can’t do the actual jumping part of it but for 60 seconds, their arms are going up and down, up and down, up and down at a very high rate, and maybe their legs are moving, too—and that’s high intensity for them. For others of you, it may be doing a two-minute walk up a very steep hill. The intensity of the exercise stresses the heart in ways that a nice easy walk does not. And for that, you get additional benefits, no matter where you’re starting.

So check with your doctor to find out your limitations as it relates to exercise intensity, and then get after it. Not to lose a whole bunch of weight, not to win the next 5K, not every day—but often enough to make your heart stronger and fitter.

What are you prepared to do today?

        Dr. Chet

P.S. Happy Canada Day to our neighbors to the north! We’re taking next week off to enjoy the July 4th holiday and hope you do as well (even if you’re not in the U.S.) We’ll be back with new Memos the week of the 10th. Meanwhile, it’s a great time to try increasing your exercise intensity.

Reference: Eur Heart J (2022) https://doi.org/10.1093/eurheartj/ehac613

How Hard Should You Exercise?

/in /by

Exercise is my most favorite thing to talk about—not surprising for an exercise physiologist. There’s no question that diet is important to our health, but if I had to focus on just one habit that people should adopt, it would definitely be exercise first before anything else. I believe we should all eat more vegetables and fruits, take supplements for gaps in our diet, and try to reach a normal body weight. But aside from quitting smoking, the most important thing you can do for your health is to be physically active.

Let’s look at the study. The subjects in the study were a subgroup of people from the United Kingdom Biobank study. The data were collected from 88,412 middle-aged adults, with 58% women, who were specifically chosen because they had not been diagnosed with cardiovascular disease before the study.

The researchers broke the data into three equal groups by activity level. The average age of the subjects in the study was 62, and the average BMI was 27. They tracked the subjects for 6.8 years, and in that amount of time there were 4,068 cardiovascular disease (CVD) events: ischemic heart disease (reduced blood flow to the heart) or cerebrovascular disease (reduced blood flow to the brain).

Their findings were interesting and confirmational. Using no or differing covariates in the statistical analysis, as the amount of physical activity increased, the incidence of CVD decreased. That would confirm what we would expect: regardless of intensity, the risk of CVD decreased and it continued to decrease for every level tested.

How does exercise intensity impact all this? We’ll take a look at intensity on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: Eur Heart J (2022) https://doi.org/10.1093/eurheartj/ehac613

The Best Heart-Healthy Diet

/in /by

In assessing popular diets to find out which one follows the AHA heart-healthy dietary guidelines the best, the panel did a credible job. Instead of just using their expertise, which is substantial, they developed an objective way of assessing each popular diet. They did have one diet that received a point for each of the nine categories thus achieving 100%. That was the Dietary Approach to Stop Hypertension more commonly known as the DASH diet.

The researchers then assessed the dietary patterns and organized them into four tiers based on compliance with the AHA guidelines. I’ll break it down into the tiers for you.

Tier 1

This tier includes the DASH diet, the Mediterranean diet, the pescatarian or fish as protein, and the ovo-lacto vegetarian diets. The primary reason that the DASH diet ranked so high was its ability to get protein from every source: plant proteins such as nuts and legumes, fish and seafood, low-fat or fat-free dairy, and the ability to use lean cuts of all meats. The other diets in Tier 1 either did not recommend proteins from all sources or did not emphasize reducing the amount of salt intake, a key element of the DASH diet.

Tier 2

Tier 2 included the vegan diet and other low-fat diets. Their strength, of course, is the emphasis on vegetables and fruits as well as whole grains, but they all seek to use plant-based protein. Some of the low-fat diets can be quite extreme, such as the Esselstyn Program which restricts fat to less than 10% per day and restricts protein as well.

Tier 3

This included the very low fat diets as well as the low-carbohydrate diets. The reason these two are put together is the restriction on quality protein sources as well as whether people adhere to the diet at every meal.

Tier 4

The paleo diet and very low carbohydrate diets such as the ketogenic diet received the worst scores; that means they fall into the category of not being heart healthy at all.

Other Considerations

The panel also considered three primary issues. The first was how easy it would be to facilitate patients to adapt to the particular diet. To me, the strength of the DASH diet and to some degree the Mediterranean diet is the variety of proteins that can be used. When you get into the very low fat and the very low carbohydrate diet, the restrictions can become overwhelming for most people.

They also considered the challenges for the consumers. In my experience, there are always going to be questions about what could be included in any dietary approach, whether it’s the Mediterranean diet or the ketogenic diet. In order for people to adapt the diet, they need instruction and they need to be able to ask questions; those would be significant challenges when recommending the diets that restrict foods allowed, which could either be vegan, the very low fat, or the ketogenic diet.

The final consideration is the opportunities presented to provide patients with good information about the diet. The problem as I see it is that physicians, physician assistants, and nurse practitioners are not familiar enough with nutrition to be able to do that effectively in a medical practice, especially considering the time constraints for most healthcare practitioners. The obvious choice is to refer it to a dietetics department, but that type of consultation is not very often available in most medical practices and especially under most health insurance programs. I think the challenges are going to take years to overcome.

My Thoughts

I thought the researchers did a credible job in coming up with their recommendations. They analyzed popular diets objectively and assessed them based on the AHA Dietary Guidance.

What is lost is exactly how this is going to help people. Since 1974, more fruits and vegetables and a limit on fat intake were recommended as the foundation of every diet. No matter how many diets have come and gone, no matter how many are yet to be developed, we have not achieved the simplest and yet most obvious objectives. Food manufacturers certainly have had a role to play in this with low-fat and ultra-processed convenience food, but the choice is always with us.

There are three more things that I think must be considered. First would be the individual’s genetic tendencies. We simply don’t know enough about interaction between genes and nutrition and how that impacts input. Second, protein needs change over a lifetime. At some point, proteomics must be considered in dietary recommendations; it isn’t all about your heart.

Finally, they specifically did not consider the potential for weight loss or weight maintenance in every program. Regardless of diet, it was, it is, and it will always be about the calories. If someone can get to a normal body weight and maintain it, I think there might be room for just about any type of diet, providing it provides enough vegetables and fruits.

The Bottom Line

As the lead author suggested in an interview, there were four recommendations across all popular diets: eat whole foods, eat more non-starchy vegetables, eat less added sugar, and eat less refined grains. If we could start with that, I think our hearts would love us for it.

What are you prepared to do today?

        Dr. Chet

Reference: https://www.ahajournals.org/doi/10.1161/CIR.0000000000001146

How Popular Diets Impact Your Heart

/in /by

When the American Heart Association (AHA) speaks, news organizations tend to report what they say and people tend to listen. It’s doubly true when they rank all the popular diets according to how they relate to heart health. Because we seem to live in a society based on the “see food, eat food” diet, that can be meaningful. Here’s what a group of experts did to evaluate popular dietary approaches to diet and rank them according to AHA guidelines for a heart-healthy diet.

The AHA has ten dietary guidelines for eating a heart-healthy diet, such as “Eat plenty of vegetables and fruits” and “Choose healthy sources of proteins.” For the complete list, click on this link to the article; the scientific statement is open access on the AHA website.

Then the panel selected the most popular diets in the U.S. such as the Mediterranean diet, the DASH diet, several versions of a vegetarian diet, low-fat, paleo, and ketogenic diet. They gave each diet a full point for following each of the AHA guidelines or partial points depending how closely they followed the guidelines.

This was not an arbitrary assignment by a panel of experts; they used the best information available to determine the best heart-healthy diet. Who got the highest score? Mediterranean? Vegan? Ketogenic? I’ll let you know on Saturday along with my thoughts on the diets. One thing’s for certain: eat your fruits and vegetables. You may as well start with that right now.

What are you prepared to do today?

        Dr. Chet

How Coffee Relates to CVD

/in /by

Researchers in Germany used a unique approach in the Hamburg City Health Study: they selected the first 10,000 volunteers. Volunteers who didn’t drink coffee were eliminated from the study, so they ended up with 9,009 subjects.

The researchers collected dietary data along with a variety of other demographic and physiological variables, integrating lifestyle-related behavior, comorbidities, biomarkers, electrocardiographic and echocardiographic data, and finally major cardiovascular diseases (CVDs). They divided up the subjects by coffee intake: low = less than three cups a day, medium = three or four cups per day, and high = more than four cups of coffee per day.

Results

This epidemiological cross-sectional study resulted in the following:

  • High coffee consumption correlated with slightly higher LDL cholesterol
  • Moderate and high coffee consumption correlated with lower systolic blood pressure and lower diastolic blood pressure
  • Different levels of coffee intake didn’t impact heart rhythms or function
  • Most important, coffee intake did not impact the presence of CVD nor prior cardiac events such as heart attacks and heart failure

Were the results of coffee and LDL cholesterol concerning? No—the difference was just five mg/dl, well within measurement error.

Is Coffee Safe to Drink?

Coffee was always safe to drink; the question was how our bodies responded to consuming it. Neither of these studies was perfect, but they show that even high coffee consumers, including myself, may not be at any significant risk for promoting or advancing CVD or cardiovascular events.

I think for most people coffee and caffeine are closely linked. What most of us don’t realize is that coffee is a complex liquid consisting of more than 1,000 bioactive substances, including phytochemicals that have proven beneficial for many organ systems; it’s not only a nervous system stimulant because of the caffeine content.

The Bottom Line

When it comes to coffee, I think it’s person-specific. Taste aside, some people may process caffeine differently, which may impact how much coffee someone could enjoy. These studies add to a body of work which shows that coffee is safe for the heart and other organs; other benefits or issues require further study. For me, time for another mug of Sumatra Roast.

What are you prepared to do today?

        Dr. Chet

Reference: https://www.nature.com/articles/s41598-023-31857-5

Research Update: Coffee and Heart Rhythms

/in /by

In one of the first jobs I ever had, the foreman would pour a half-cup of coffee and fill it up with water; he’d had a heart attack and his doctor told him to limit his coffee intake. Fifty years ago, physicians recommended that people avoid coffee if they had high blood pressure or had a cardiac event such as a heart attack. The thought was to lower the stimulating effect of caffeine to keep heart rate and blood pressure lower. In the interim, some studies showed that coffee contributes to cardiovascular disease and more recently, that it may not. So if you love coffee the way I love coffee, you may be encouraged by a couple of recent studies.

The first study examined the effect of coffee on heart rhythms in 100 subjects with a mean age of 39 who served as their own controls. All subjects had a variety of blood tests as well as genetic tests to determine if they were fast or slow processors of caffeine. They also wore a new-age heart rhythm monitor for the 14 days of the study. I’ve worn that monitor, and it gives accurate EKGs to monitor heart rate and heart rhythm abnormalities such as premature atrial contractions and atrial fibrillation.

The subjects were notified the evening before whether they were going to be on a two-day coffee drinking cycle or two-day caffeine avoidance; the idea was to track immediate impacts. The good news: there were no differences in abnormal rhythms on coffee days versus non-caffeine days and no impact of caffeine processing. One interesting observation: on the days subjects drank coffee, they walked more steps. We’ll look at the impact of coffee on cardiovascular disease events on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: N Engl J Med 2023;388:1092-100.

Food or Supplements? Yes!

/in /by

The results of the polyphenol study examining the impact on cardiovascular (CVD) risk factors were mixed. Here’s what the researchers found:

  • Neither the polyphenol-rich foods (berries, spices, herbs, teas, nuts, seeds, etc.) nor extracts had a significant effect on LDL- or HDL-cholesterol, fasting blood glucose, IL-6, and C-reactive protein.
  • When looking at the studies using polyphenol-rich food, there was a significant decrease in systolic and diastolic BP.
  • The polyphenol extracts had a significant effect on total cholesterol and triglycerides and had a greater reduction of waist circumference.
  • However, when both whole-food polyphenols and polyphenol extracts were used together, there was a significant reduction in systolic BP, diastolic BP, endothelial function, triglycerides, and total cholesterol.

The Upside

Polyphenols in foods and supplements were effective in reducing risk factors for CVD, both independently and when combined. This wasn’t a seminal paper that changes approaches to nutrition forever, but there were benefits. I think that’s something that was needed. It supports what my approach has always been: eat as healthy a diet as you can, and fill in the nutritional gaps with supplements.

The Problems

There were several issues. The studies included in the meta-analysis had little cohesiveness as to subjects used, sources of the foods, or the type of supplements; some used capsules while others used juices or drinks.

The issue with foods, among many, is the digestion and absorption of the active polyphenols. There’s competition with other nutrients and then the issue of the microbiome—is it functioning properly in every subject?

The issue with supplements, besides the delivery system, is whether the dose is appropriate or therapeutic. Would the amount of quercetin found in apples be the correct dose, or would you need to eat 10 apples? Would it respond the same way in the body isolated from the other polyphenols, or would another factor come into play?

The Bottom Line

In spite of its flaws, I think this study was fantastic. It demonstrated that nutrients extracted from foods can be effective in reducing CVD risk. It demonstrated that foods alone aren’t the answer and neither are supplements; it’s their use in a complementary fashion where the benefits may be found. The researchers set the stage for putting more effort into nutrition research, because there’s so much we don’t know. Yet. Until then, your best bet to support your health is to eat your vegetables and fruit, add herbs and spices, munch on seeds and nuts—and then supplement your diet with quality supplements.

What are you prepared to do today?

        Dr. Chet

Reference: https://www.sciencedirect.com/science/article/pii/S2161831323000029

Food or Supplements?

/in /by

One of the changes I’ve made in selecting topics to write about in these Memos is to read the table of contents of the scientific journals to which I subscribe, especially the nutrition journals. It’s easier to see what’s controversial by looking at news feeds, but they miss a lot of positive nutrition science. One question that’s ever-present is this: when it comes to nutrients, is getting nutrients from supplements as good as getting nutrients from food?

Researchers searched four databases of scientific journals to find randomized-controlled trials that examined the effect of either polyphenol-rich foods or polyphenol extracts on risk factors for cardiovascular disease (CVD). It’s estimated that there are more than 8,000 types of polyphenols, including flavonoids, polyphenolic amides, phenolic acids, resveratrol, and ellagic acid. You’ll find polyphenols in fruits, vegetables, spices, herbs, teas, nuts, and seeds.

They found over 1,100 studies that fit the profile. Using subject, statistical, and nutrient criteria, they whittled the number of studies down to 46. Then they conducted a meta-analysis of the impact of food and supplements on the following CVD risk-factors: systolic BP, diastolic BP, endothelial function, fasting blood glucose, total-, LDL-, and HDL-cholesterol, C-reactive protein, Il-6, and waist circumference.

Nutrition studies are usually messy, and this one was no exception. I spot-checked the 46 studies and found different foods for the polyphenol sources and different extracts for the supplements. Still, it was as well-done as such a study could be. I’ll give you the results on Saturday.

Tomorrow night is the Insider Conference call for March. The topic is the absorption of omega-3s, and I’ll also answer your questions. Become an Insider by 8 p.m., and you can participate in this live event.

What are you prepared to do today?

        Dr. Chet

Reference: https://www.sciencedirect.com/science/article/pii/S2161831323000029

Why Are You Napping?

/in /by

I think people get frustrated with research because, just like I’ve described this week, one study says one thing while another comes to different conclusions. I hope that if you’ve been reading the Memo long enough you won’t be frustrated. In this case, why might studies that seem similar on the surface come up with different results?

First, while the studies seemed to ask the same questions, the studies actually had different objectives. In the Swedish study that showed a reduction in cardiovascular disease (CVD) events for those napping once or twice a week, the subjects were selected because they had not had any cardiac events or diagnosis of CVD. That means that any CVD that took place in the follow-up period was a primary event. In the other two studies, high-risk CVD events were excluded in one but other CVD factors were allowed such as hypertension.

Second, the purpose of the Swedish was designed to look at the development of CVD. The other two studies from Switzerland and the U.K. recruited over 500,000 subjects, but the research questions appeared to be decided after the studies began. There’s nothing wrong with that, but just because you have collected data on many variables, including genetics, doesn’t mean the data collected answer the research questions that were asked.

For example, the premise was that daytime napping causes CVD and hypertension. It seems likely that those conditions could cause fatigue, which would require daytime napping. Even if that were not the case, the subjects appeared to already have problems sleeping, which would impact hormone levels that contribute to CVD such as cortisol levels and many others.

The Bottom Line

These large studies attempted to make sense out of prior research that showed a link between daytime napping and CVD. What I think these studies demonstrate is that the cause of the nap is important. If it’s a planned nap designed to allow digestion or a pause in a long work day, it may not be hazardous to your heart health. However, if a person doesn’t sleep well or has sleep apnea and is fatigued because of that, being forced to nap during the day to recover can indicate a higher risk of developing CVD and hypertension.

Diet, body mass, lack of exercise, and other factors all have a role to play in sleep quality and CVD as well. If you plan your nap, you’re in control. If you’re forced to nap, time to look at your lifestyle and see what you can change.

What are you prepared to do today?

        Dr. Chet

P.S. Just for fun, these are a few of Riley’s more inventive napping positions. Oh, to be that flexible! Maybe the monkey blanket helps.

References:
1. Heart. 2019;105:1793–1798.
2. J Am Heart Assoc. 2022;11:e025969. DOI: 10.1161/JAHA.122.025969.
3. Hypertension. 2022;79:00–00. DOI: 10.1161/HYPERTENSIONAHA.122.19120.

To Nap or Not to Nap

/in /by

About 16 years ago, Paula and I spent several weeks (spread out from March to October) helping our son Matthew build his boat-building shop. The daily routine went something like this: start early, break for lunch, take a 30- to 45-minute nap, then work the rest of the day. Matthew and Kerri live near Charleston, SC, where summer temperatures aren’t really conducive to construction work, so napping during the hottest part of the day made a lot of sense, but we also found we got a lot more accomplished every day.

I’ve used that approach off and on ever since. Recently, a couple studies were published that called into question whether naps were a good idea as they might be related to cardiovascular disease (CVD).

The research news caught my attention because the last time I read a research paper about sleep and napping showed that there was no relationship between napping and cardiovascular disease. In fact, the risk over five years of follow-up was a 42% decrease in CVD events when a person took a nap once or twice a week and no risk if a person napped every day (1).

In the most recent research, there was a relationship between napping and hypertension and napping and CVD in two separate studies with thousands of subjects (2, 3). Why? We’ll delve into why there were different results on Saturday.

What are you prepared to do today?

        Dr. Chet

References:
1. Heart. 2019;105:1793–1798.
2. J Am Heart Assoc. 2022;11:e025969. DOI: 10.1161/JAHA.122.025969.
3. Hypertension. 2022;79:00–00. DOI: 10.1161/HYPERTENSIONAHA.122.19120.