preventive care

Thoughts on the Recent VeloNews Article

September 1, 2015 By Larry Creswell, MD 3 Comments

I enjoyed reading a recent article in VeloNews by Chris Case, entitled “Cycling to Extremes: Are endurance athletes hurting their hearts by repeatedly pushing beyond what is normal?” The article is good reading.

First, I give a lot of credit to Chris Case and the editors at VeloNews. It’s great that a publication with such a broad audience would devote time and space to the issue of heart health and endurance sport. In recent months, they’ve also brought attention to the heart problems of pro cyclists, Robert Gesink, Olivier Kaisen, and Eddy Merckx. I wish that other writers and publications would do the same.

I also thank Lennard Zinn and Mike Endicott for sharing their personal stories with their heart problems. It would be very easy to keep quiet. I very much enjoy reading personal accounts such as these. Their stories are real and also familiar. This is how we learn.

Since the article was published, I’ve gotten a bunch of inquiries asking my opinion about the article in general or about specific information that was presented. Let me share a few thoughts that may be helpful to readers here at the blog….

Don’t be scared (too much)! For most people, cycling is a healthy pursuit. In general, exercise is healthy and provides a myriad of benefits. So don’t stop cycling! It’s important to keep in mind that the stories of Zinn and Endicott are not the norm, even among veteran endurance athletes. Zinn’s multifocal atrial tachycardia (MAT) is one of the least common atrial arrhythmias and Endicott’s sudden cardiac death is rare. As you absorb their stories, focus not on the particular arrhythmias but rather on the possibility that an arrhythmia–any arrhythmia–can cause significant problems or be an indication that things are amiss with the heart. In that sense, their stories should cause you to put on your thinking cap.

My favorite quote from the article? “But fit for racing doesn’t necessarily equal healthy.” Readers here at the blog will know that I’ve said this repeatedly. It’s easy for seemingly healthy endurance athletes, particularly men, to believe that fitness is the same thing as healthiness. This isn’t necessarily true. To dispel the myth, I’ve shared the stories of many elite endurance athletes who’ve struggled with heart problems of various sorts. We can add Zinn and Endicott to these lists. Heart problems are common….and athletes aren’t exempt. This is the most important take-home message from the article.

Arrhythmias are common–in athletes and non-athletes, alike. All athletes experience arrhythmias. Infrequent premature beats, originating in either the atrium (premature atrial contractions, or PAC’s) or in the ventricles (premature ventricular contractions, or PVC’s) most likely have no consequence. Sustained arrhythmias, on the other hand, deserve attention and evaluation. There are far too many varieties of arrhythmias to consider here, other than to mention some of their names: SVT, or supraventricular tachycardia; WPW, or Wolff-Parkinson-White syndrome; atrioventricular (AV) nodal re-entry tachycardia; atrial or ventricular bigeminy; sick sinus syndrome; sinus bradycardia; atrial fibrillation (AF); atrial tachycardia; MAT; ventricular tachycardia (VT); and ventricular fibrillation (VF).

The last part of the VeloNews article alludes to AF. Other than sinus bradycardia (simply a heart rate slower than 60 beats per minute, which may be very healthy in athletes) or innocuous premature beats, AF is probably the most common arrhythmia in athletes. We know from longitudinal studies that the lifetime risk of having AF is approximately 25% in the general population. The question of whether athletes–and endurance athletes, specifically–are more prone to AF is a current controversy, with important implications for long-term endurance athletes. I’ll try to finish up a separate blog post that summarizes the accumulated evidence on this issue. For men, there may be an association with long-term exercise and the prevalence of AF, but there is certainly no consensus among experts. For women, the evidence does not suggest an association between long-term exercise and AF.

Pay attention to warning signs. I particularly like the last section of the article, written by Dr. John Mandrola. He’s a cardiologist who specializes in arrhythmias and who is also a (former?) triathlete and current avid cyclist. He provides good advice in the Q&A. I like to talk about 5 important warning signs of possible heart disease: chest pain or discomfort, especially during exercise; unexplained shortness of breath; light-headedness or blacking out (syncope), especially during exercise; unexplained fatigue; and palpitations–the sense of a rapid or irregular heartbeat. Any of these warning signs may be due to an arrhythmia. All deserve investigation. Dr. John makes the apt point that, very often, heart rhythm problems start off small and get worse with time. Not surprisingly, it’s best to get things sorted out earlier rather than later.

Less may be more. Lastly, I would encourage athletes with identified arrhythmias to be open to the idea that less exercise may be helpful. In fact, this may be the most appropriate prescription. For the long-term endurance athlete, this can be difficult to accept. In this regard, the stories of Zinn and Endicott are particularly poignant.

2. Atrial Fibrillation in Athletes (in a Nutshell)

3. Too Much Exercise, Revisited

4. Don’t Stop Running Yet!

Videos by Doc Mike Evans

December 9, 2013 By Larry Creswell, MD Leave a Comment

This is just a short post to draw attention to the remarkable video series by Doc Mike Evans, a family physician at the University of Toronto. Over the past couple years, he’s produced a growing collection of witty educational videos on topics ranging from concussions to flatulence to obesity. In his words, he’s trying to create a “med school for the public.” The collection of videos is available at his YouTube site.

Some of my favorites on the topic of exercise are:

Check out the videos and share them with a friend!

New ACC/AHA Heart Health Guidelines and Implications for Athletes

November 21, 2013 By Larry Creswell, MD Leave a Comment

Last week the American Heart Association (AHA) and American College of Cardiology (ACC) released a new set of Guidelines to Reduce Cardiovascular Risk. In just a few short days, these Guidelines have received a great deal of attention–and a fair bit of controversy–in medical and scientific circles. They’ve also caught the attention of the popular media and have generated a lot of discussion.

Let’s take a moment to remember that heart disease remains the #1 killer of both men and women in the United States. About 600,000 deaths annually are due to heart attack and another 130,000 are due to stroke. There is obviously ample reason to care about heart disease prevention–and that is what these new Guidelines are all about.

The Guidelines are targeted at primary care providers–the doctors and other medical professionals who provide routine, long-term care for their patients. All of us should be aware of these Guidelines, though, because they will shape the way the medical community approaches heart disease prevention for years to come.

Let’s take a look at the Guidelines and how they relate to athletes, specifically.

The Guidelines

The new Guidelines have been offered electronically online in preliminary form. They will soon be published in the organizations’ medical journals, Circulation and the Journal of the American College of Cardiology.

There are actually 4 separate Guidelines:

2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk
2013 ACC/AHA Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults
2013 ACC/AHA Guideline on Lifestyle Management to Reduce Cardiovascular Risk
2013 ACC/AHA Guideline for the Management of Overweight and Obesity in Adults.

These Guidelines have been long in the making. With efforts that began in 2008, each of the Guidelines was developed by a panel of experts which conducted a thorough review of the relevant scientific evidence that had been accumulated through 2011. In the end, the panels reached consensus about conclusions that could be drawn from the evidence and constructed the Guidelines to help guide primary care providers in the care of their patients.

As a whole, the Guidelines aim to match the intensity of prevention efforts to an individual’s absolute risk of future atherosclerotic cardiovascular disease (ASCVD).

Guideline #1–Assessment of Cardiovascular Risk

For a variety of heart-related treatment decisions, it has been important to have an estimate of a patient’s future risk of having a major cardiovascular event such as a heart attack (myocardial infarction, MI). Examples would include decisions about the type and intensity of treatment for elevated serum cholesterol or lipid levels, the use of aspirin for the prevention of a future MI, or the type and intensity of treatment for high blood pressure.

Several prediction tools have been available. The most popular tool is the Framingham 10-year risk score which was first proposed in 1998 and has been updated several times since. The Framingham risk score was modeled using data obtained over several decades from the Framingham Heart Study. The risk score is based on an individual’s age, sex, serum total cholesterol and HDL cholesterol, smoking history, systolic blood pressure (the upper number), and the use of medications for blood pressure control. The risk score predicts the 10-year risk of developing coronary heart disease (CHD)–heart attack, or MI. The Framingham risk score does not predict the future risk of other important cardiovascular outcomes such as stroke, mini-stroke or transient ischemic attack (TIA), or heart failure. Moreover, since this score was based on data gathered from only White populations, the Framingham risk score has always been criticized for its generalizability to other patient populations.

With the new Guidelines, we now have a risk calculator that applies to a much broader patient group that includes the U.S. White and African American populations from age 40 to 79 years. The expert panel developed new equations for the prediction of 10-year risk of developing a broader set of endpoints that now include the combination of nonfatal MI, CHD death, and fatal or nonfatal stroke. As a group, this set of endpoints is referred to as atherosclerotic cardiovascular disease (ASCVD).

The prediction equations are currently implemented in an Excel spreadsheet Risk Calculator that can be downloaded from the AHA or ACC websites. Users will see that their 10-year risk is based on their inputs of age, sex, race, total cholesterol, HDL cholesterol, systolic blood pressure, use of blood pressure medication(s), diabetes, and smoking. The prediction equations are intended for the adults who do not already have known ASCVD.

In addition to the creation of the Risk Calculator, the expert panel made several recommendations about its use:

Traditional risk factors for ASCVD (age, sex, total cholesterol, HDL cholesterol, systolic blood pressure, use of blood pressure medications, and current smoking) should be assessed every 4-6 years in adults 20-70 years of age.
The Risk Calculator should be used every 4-6 years to estimate the 10-year future risk of ASCVD in individuals 40-79 years of age.
For patient groups other than non-Hispanic Whites and non-Hispanic African Americans, the equations for non-Hispanic Whites should be used.
If a treatment decision remains uncertain after the Risk Calculator is used, then additional factors such as family history of heart disease, serum C-reactive protein level (>2 mg/dL), coronary artery calcium (CAC) score from a cardiac CT scan (>300 Agatston units or >75th percentile for age), or ankle-brachial index (ABI) <0.9 may also be taken into consideration.
The value, if any, of using serum apolipoprotein B, chronic kidney disease, albuminuria, carotid artery intima-media thickness, or cardiorespiratory fitness as additional risk factors is not yet established.

Implications for Athletes

Many athletes will have a favorable risk profile. They will have a normal blood pressure, be non-smokers, and have normal values for the serum cholesterol and lipids. But even healthy athletes should take the time for periodic assessment of their cardiovascular risk factors starting at age 20. Ideally, this would be accomplished with the support of your doctor. But even without a doctor, athletes should remember to have the serum cholesterol and lipids checked every 4-6 years. Remember, too, that age alone is a risk factor–and none of us can escape the fact that we continue to age!

Middle-aged athletes often ask about the value of additional diagnostic testing to help quantify their future risk of CHD or even sports-related sudden cardiac death (SCD). And either alone, or in conjunction with their doctors, they pursue testing such as measurement of the serum CRP or a cardiac CT scan for CAC score. These tests should be used with discretion. They are most helpful when a specific treatment decision must be made (eg, deciding whether to start a new cholesterol-lowering medication) and the new Risk Calculator suggests that the decision could reasonably go either way.

Guideline #2–Treatment of Blood Cholesterol to Reduce Atherosclerotic Risk in Adults

The second Guideline focuses on the use of cholesterol-lowering statin medications (eg, Lipitor, Zocor) to reduce cardiovascular risk. This new Guideline provides a fresh approach to the use of these cholesterol-lowering agents in the prevention of heart disease. The Guideline also recognizes that “lifestyle modification (i.e., adhering to a heart healthy diet, regular exercise habits, avoidance of tobacco products, and maintenance of a healthy weight) remains a a critical component of health promotion and ASCVD risk reduction, both prior to and in concert with the use of cholesterol-lowering drug therapies.”

Our former guidelines about cholesterol-lowering medications come from the National Institutes of Health and their National Heart Lung and Blood Institute (NHLBI) Adult Treatment Panel (ATP) III, last updated in 2004. These guidelines advocated the use of cholesterol-lowering medications for specific elevation levels of the LDL cholesterol and total cholesterol and specified absolute target levels for their reduction.

In contrast, the new Guideline recognizes that there is actually no credible scientific evidence to support the use of specific target levels for the LDL cholesterol or total cholesterol. Furthermore, the Guideline advises that non-statin medications do not provide acceptable ASCVD risk reduction to justify their use.

The expert panel identified 4 groups of individuals who benefit from statin medications:

Individuals who already have ASCVD
Individuals with elevation of the LDL cholesterol >190 mg/dL
Individuals 40-75 years old with diabetes and LDL 70-189 mg/dL
Individuals without ASCVD or diabetes who are 40-75 years old, with LDL 70-189 mg/dL and an estimated 10-year risk of ASCVD of 7.5% or higher.

The newly developed Risk Calculator is the tool that should be used to determine an individual’s 10-year risk of ASCVD.

In groups #1 and #2, the Guideline advises using high-intensity statin therapy that usually reduces the LDL cholesterol by 50% or more. In group #4, moderate-intensity statin therapy that usually reduces the LDL cholesterol by 30-50% is advised. In group #3, either moderate- or high-intensity therapy could be warranted, depending upon the patient’s 10-year risk of ASCVD.

About 25% of Americans already take these medications. With these new Guidelines, it is estimated that about 50% of African American men and 35% of White men in their 50’s would qualify for a statin drug. And similarly, 50% of African American women and 35% of White women in their 60’s would qualify. Category #4 (adults without ASCVD or diabetes who have a 10-year ASCVD risk of 7.5% or greater) is thought to represent about 30 million Americans. So obviously with full implementation of these guidelines, more Americans will be taking statin medications.

Implications for Athletes

Exercise has a very favorable influence on an individual’s lipid profile, lowering the LDL cholesterol and total cholesterol and raising the HDL cholesterol. Exercise also has a favorable influence on the blood pressure. These beneficial effects are taken into account in the Risk Calculator used to predict the 10-year risk of ASCVD.

There are athletes who fall into groups #1, #2, and #3 because they’ve already had a heart attack or stroke, or have severe elevation of the LDL cholesterol, or have diabetes. By and large, these are individuals who already have a reason to be taking a statin medication. The new Guideline is no different here.

With the new Guideline, group #4 is most interesting. I suspect there are many athletes who fall into this group, but who currently do not take cholesterol-lowering medications. Remember, this group now includes adults 40-75 years old with a 10-year ASCVD risk greater than 7.5%. We previously thought that a 10% risk threshold was needed to justify the use of statin drugs. Athletes in this group should have a discussion with their doctor about the use of statin medications to reduce their cardiovascular risk.

One of the known side effects of statin medications are muscle symptoms such as pain, tenderness, and cramping. In athletes with these symptoms it can sometimes be difficult to sort out whether the symptoms are due to the medication or to the athlete’s exercise routine. The new Guideline advises:

Establish a baseline related to muscle symptoms before starting a statin drug
Stop the medication if new muscle symptoms develop, to allow time for evaluation for other potential causes of the muscle symptoms
Restart the medication if no other cause is found, trying to identify a causal relationship between the statin drug and the symptoms. If that is the case, change to a lower dose of a different statin medication.

Guideline #3–Lifestyle Management to Reduce Cardiovascular Risk

The third new Guideline recognizes the role that dietary patterns, nutrient intake, and levels and types of physical activity play in the risk of ASCVD, particularly through their influence on the modifiable risk factors such as blood pressure and serum cholesterol and lipids.

For both lowering of the LDL cholesterol and for lowering the blood pressure, the Guideline recommends “a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils and nuts; and limits intake of sweets, sugar-sweetened beverages and red meats.” Examples of such diets are the DASH dietary pattern, the USDA Food Patterns, or the AHA Diet.

Additional recommendations include limiting saturated fat in the diet to 5-6% of total calories, reducing the percentage of calories from trans fat, and limiting sodium intake to 2,400 mg per day.

The Guideline recommends aerobic exercise for its beneficial effect on the LDL cholesterol and blood pressure, suggesting an exercise routine of 3-4 sessions per week, lasting ~40 minutes per session, and involving moderate to vigorous physical activity.

Implications for Athletes

There should be no real surprises with this Guideline.

Although there are advocates for many other particular diets, this Guideline recognizes that their benefit with regard to ASCVD risk reduction is not established. In some cases, these other diets may be good, but there are simply no studies to prove it.

The many health benefits of exercise are well established. Obviously, physical activity has a beneficial effect in terms of ASCVD risk reduction, but there are many other benefits as well.

Guideline #4–Management of Overweight and Obesity in Adults

The final Guideline addresses the management of overweight and obese adults. This Guideline was written in conjunction with The Obesity Society and is endorsed by a host of other national organizations.

The Guideline recognizes that in 2009-2s010, there were 78 million adults in the United States with obesity, a condition that is associated with high blood pressure, abnormal serum lipid profile, type 2 diabetes, CHD, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory problems, and some forms of cancer. The new Guideline reaffirms our current definitions of body mass index (BMI) related to obesity:

Overweight, BMI 25-29.9 kg/m2
Obesity, BMI 30+ kg/m2

Using those definitions, approximately 69% of the American adult population is overweight, including 35% who are obese.

The Guideline suggests that a modest reduction in weight of 3-5% in overweight and obese adults may lead to meaningful benefits in terms of triglyceride levels, blood glucose, hemoglobin-A1c, and the risk of developing type 2 diabetes. A greater reduction in weight may lead to meaningful benefits in terms of lowering the blood pressure, improving the LDL and HDL cholesterol levels, reducing the need for medications to control the blood pressure, and further reduce the serum triglyceride and glucose levels.

A diet should be prescribed for overweight and obese individuals, preferably with the assistance of a nutrition professional. A variety of dietary approaches may be suitable, but the successful diet will produce an energy deficit of 500 kcal or more per day. Special caution is advised when an ultra-low calorie diet (<800 kcal/day) is prescribed. No single dietary approach was found to be superior.

In addition to a prescribed diet, overweight and obese individuals will benefit from a “comprehensive lifestyle intervention” that includes physical activity (200-300 min/week), monitoring of the diet and physical activity by a trained “interventionist,” and long-term weight maintenance programs for those who are initially successful with weight loss.

Bariatric surgery is recommended for motivated individuals without successful weight loss using first-line treatments, who have BMI >40 kg/m2 or BMI >35 kg/m2 along with associated obesity-related comorbid conditions. The most appropriate specific type of bariatric surgery will depend upon patient-related factors.

Implications for Athletes

Again, there are no surprises here. This Guideline is very much in keeping with current thinking and practice. For overweight or obese individuals who are beginning a new exercise program, it is encouraging that just 3-5% weight reduction might provide meaningful health benefits. The Guideline makes clear that new exercise programs undertaken in a setting of intentional weight loss should be monitored carefully by a physician.

Related Posts:

Podcast with IMTalk

August 2, 2013 By Larry Creswell, MD Leave a Comment

Earlier this week I had the chance to chat with John Newsom and Bevan Eyles at IMTalk for a segment on an upcoming podcast. Their weekly show originates from Christchurch, NZ and focuses on long-distance triathlon.

When the podcast is available, around August 20th, I’ll put the link here.

We talked about heart health and endurance sport and some of the new information about heart problems that might be caused by too much exercise. We also touched on last year’s report from USA Triathlon about race-related fatalities. Two other recent podcasts in their series contained a segment with Dr. Tamsin Lewis, a doctor and professional triathlete, and a segment with Dr. Douglas Scott, a cardiologist and elite age-grouper. Both segments are devoted to heart issues and are worthwhile listening.

From the Mailbag: Pre-participation Screening

May 28, 2013 By Larry Creswell, MD 1 Comment

Last month at Endurance Corner we invited readers to submit their heart-health questions. In today’s column, I did the first periodic installment of From the Mailbag. I answer Gavin’s question about how to go about screening for heart conditions that might place athletes at risk for sudden cardiac death (SCD) during a triathlon. I review information about causes of sports-related SCD and then describe a general approach to pre-participation screening for athletes. This involves careful medical history-taking, physical examination, and judicious use of other diagnostic tests such as EKG, echocardiogram, or stress test.

Please drop me a line if you have a heart-health question that might serve as the basis for an upcoming From the Mailbag column.