Athlete's Heart Blog

Dr Larry Creswell

Dr. Larry Creswell on athletes and heart health.
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A Weekend in Atlantic City

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AquabikeFinish

A couple weeks ago, I had the chance to spend the weekend in Atlantic City, New Jersey for the Challenge Atlantic City triathlon.  You may know that this was the inaugural edition of the race and the first iron distance triathlon by Challenge in the United States.  It was a terrific event and I had a great time.

I hadn’t visited Atlantic City for about 25 years.  Of course, there are new casinos now, both on and off the Boardwalk, but in many ways Atlantic City was very much like I remembered.  It’s a very unique combination of nostalgic Boardwalk beach town Americana and the business of towering casino hotel developments.  There’s new and old.  Shiny and dull.  Have and have not.  The differences are very striking.

It’s an unusual setting for a long-distance triathlon.  No doubt, it’s difficult to produce a 140.6-mile event in any urban setting, yet alone in the middle of the summer tourist season at a beach resort town!  I give the organizers a lot of credit for getting things together.

Thanks to a kind invitation from Brad Bernadini, MD, and the race director, Robert Vigorito, I had a chance to be involved with a 2-day Sports Medicine Symposium in the days before the race.  I gave talks on “Athlete’s Heart:  Good and Bad” and on “Triathlon Fatalities.”  The program included a variety of topics.  My favorite speaker was Robert Laird, MD, the long-time medical director of the Ironman World Championship.  He shared the fascinating tale of medical coverage at the event over the past 30 years.  My favorite slide was of Dr. Laird, stethoscope around his neck, standing on the Kona pier watching the first Kona edition of the race, in 1981.  That year, he was it.  Today, the event stages a 50- to 60-bed medical tent to take care of the athletes on race day.  I’ll devote my next blog post to some thoughts about medical tents at large endurance sports events.  I have mixed feelings.

As for the race, I chose to do the aquabike event.  This was a first.  I suppose there have been instances where I haven’t finished a triathlon, stopping on the run.  But this was the first time I’ve ever intentionally stopped the race at T2.  And I must say that race day has a very different feel when you don’t have to run a marathon after the long swim and bike!  Aquabike may be calling my name.

The swim portion of the race was deceptively challenging.  Held in the “back bay,” the venue was subject to a brisk incoming tide that produced a very strong current.  That, combined with a very unusual serpentine single-lap course made for a difficult swim.  As an interesting surprise on race morning, the water temperature was 80 degrees, so no wetsuits were allowed.  Most triathletes don’t have much opportunity to do 2.4-mile swims without a wetsuit.  It was a beautiful, sunny day, though, and the temperatures were mild.

The bike leg of the race took us away from the beach, up the Atlantic City Expressway (ACE), to the town of Hammonton.  There, we had two ~22-mile laps through the countryside which is apparently the U.S. capitol of blueberry farming.  There was a rewarding stretch through main street Hammonton on each lap where there were hundreds of cheering spectators, balloons, inflatable archway, and an announcer.  The race even provided shuttle buses for spectators who wanted to make the trip to Hammonton to watch the athletes.  This was a nice touch.  The ride back down the ACE to the beach was tough, into a ~15 mph headwind.  For me, at any rate, the ride didn’t seem “flat and fast,” as advertised!

I hope that Challenge is successful in getting this race established.  I understand there is a 5-year commitment at this point.  I appreciate the alternative to the series of World Triathlon Corporation (WTC) Ironman-branded events and I appreciate the choice of a venue in Atlantic City.  If you’re a triathlete, check out this race.  If you’re a medical or allied health professional, check out the pre-race sports medicine symposium.  And if you’re both….you can have a busy weekend next June!

Like I said, I was glad that my day was finished after the 112-mile bike ride.  After a shower–and a casino buffet meal–back at the hotel, I made my way to the finish line on the Boardwalk in front of historic Boardwalk Hall.  Most of the 26.2-mile run took place on the Boardwalk amongst the thousands of visitors.  It was really a sight.  And, as always, it was a thrill to see the athletes finishing late in the evening.  In Challenge style, children or family members were allowed to join athletes in the finishing chute.  The children seemed to draw the biggest cheers from the crowd.

 

 

Medical Toll at Obstacle Race

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A couple weeks ago I wrote about the medical toll at long-distance running events.  There was also a recent report on the medical toll at an obstacle course race that caught my eye.  On the face of it, the findings were surprising!

At the outset, let me issue a disclaimer.  I haven’t participated–or even spectated–at one of these obstacle course races, so I may not have the best perspective.  I’m talking, though, about races like the Tough Mudder, Warrior Dash, and Spartan Race, among others.  They’ve become very, very popular very, very quickly.  We’re talking 100’s of thousands of participants per year in the U.S.  One day, I’ll give it a try.  I’ll need to be brave!

 

The Study

A group of investigators headed by Marna Greenberg, DO, MPH, in the Department of Emergency Medicine at Lehigh Valley Hospital reported on a collection of patients who required hospital care stemming from their participation in an obstacle course race.  The event was the Tough Mudder Philadelphia race, held over the weekend of June 1, 2013.  As you may know, the Tough Mudder races are characterized by a 10- to 12-mile course with a series of 20-25 obstacles spread over the course.  By report, approximately 22,000 individuals participated in this particular race.

The investigators were the emergency room physicians at the hospital that was designated to care for participants who required hospital care for medical conditions or injuries that developed during the race.  In a report in the Annals of Emergency Medicine entitled “Unique Obstacle Race Injuries at an Extreme Sports Event:  A Case Series”, they share their first-hand experience which they characterized as surprising.

 

The Results

The report provides fair detail about 5 patients with “significant” injuries or diagnoses and compiles a list with pertinent findings in 43 total athletes who received care at the hospital. The 5 athletes with “significant” problems included:

  • 18 year old with myocarditis (inflammation of the heart muscle) caused by electrical shock during the event.  Required admission for 2 days.  Self-limited.
  • 28 year old with depressed level of consciousness and diagnoses of accelerated hypertension (high blood pressure) and pericarditis (inflammation of the sac that holds the heart).  Required admission for 2 days.  Self-limited.
  • 31 year old right-sided weakness who was found to have a stroke, seizure, and dehydration.  Required admission to the intensive care unit (ICU).  Was discharged to a rehab facility and at the time of writing, had persistent weakness due to the stroke.
  • 41 year old who experienced syncope (blacked out) after being shocked at an obstacle.  He fell, causing lacerations to the face.  He was discharged from the emergency room against medical advice to be hospitalized.
  • 25 year old woman with near syncope (nearly blacking out) because of electrical shock.  Required hospitalization for evaluation and was treated for dehydration and rhabdomyolosis (breakdown of muscle).

The 38 others had diagnoses that included:  heat injury, sunburn, ear barotrauma (pressure injury), shoulder dislocation, patella dislocation, heat exhaustion, vomiting, renal failure, various contusion injuries, rib fracture, dehydration, asthma, seizure, leg fracture, ankle sprain, and elbow sprain, among others.

 

The Takehome Messages

You never read about the medical toll at running races that are shorter than half marathon distance.  That’s not to say that athletes don’t have injuries or other medical problems manifest during those races.  It’s just that athletes are usually responsible for their own medical care or receive their care from the emergency medical system (EMS), rather than by race-supplied medical volunteers.  So nobody is keeping track of the “toll.”

This report is great peak into the issues with the obstacle races.  Kudos to the authors for sharing their experience.  Obviously, 43 victims among 22,000 participants is a small fraction.  We might reasonably expect, though, that additional athletes with minor injuries or medical conditions did not visit the hospital for care.

Some thoughts….

  • At an obstacle course race, the obstacles present a challenge and risk that is different from just running.  These events are certainly not risk-free.
  • There are typical medical issues like minor injuries, dehydration, and heat injury.  Some injuries and medical problems may be due very specifically to the obstacles themselves.
  • There will also be injuries that may not be expected–either by the athletes or by the nearby healthcare workers.  At this particular event, the myocarditis, pericarditis, stroke/seizure, and syncope diagnoses were examples.  Electrical shock was an unexpected causative factor.
  • Athletes should keep the potential risks in mind when they decide to participate and exercise great care while participating.

Like I said at the top, I’ll probably be a participant at some point.  But I’ll need to be brave!

Book Review: Cardiac Athletes

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CardiacAthletesBookHot off the press is a new book by Lars Andrews, entitled simply, Cardiac Athletes.  I had a chance to read the book over the July 4th holiday weekend and I thought I’d share some details here at the blog.  I enjoyed the book and recommend it highly.

Lars Andrews is the founder of Cardiac Athletes, the worldwide support community for athletes with heart disease.  I’ve written previously here at the blog about the organization’s many activities.  You can find them online at their website and also on Facebook.  If you’re an athlete with heart disease, you’ll find an active online forum that helps athlete patients make useful connections with others in similar circumstances.  On the charitable front, the organization raises money to support donation of automatic external defibrillators (AEDs) to communities in need and to support cardiac screening programs for athletes.

This new book will be good reading for a variety of folks–athletes, of course, with heart disease; healthcare workers who care for these athlete patients; and pretty much anybody who enjoys reading inspirational personal stories from athletes.

Andrew LaGerche, MBBS, PhD, a physician-scientist, himself a talented endurance athlete, and with a long professional interest in athletes and heart disease, writes a great Foreword.  In the Preface, Andrews details the history and evolution of the Cardiac Athletes organization and sets the stage for the remainder of the book.  The Introduction features his take on 10 repeating themes that will be found in the athlete stories:  cardiac athletes are pioneers; we need sports cardiology centres; are we starting to see a post athletic epidemic?; would preschool screening be bad?, among others.

The bulk of the book is a collection of the personal stories from 17 athletes affected by heart disease.  Each athlete shares his/her journey from the discovery of their problem, through its diagnosis and treatment, and the long-term consequences.  In many cases, there are illustrations which bring clarity to the specific heart problem being described.  This is very helpful to non-medical readers who won’t be familiar with the details.  Each chapter is a rare, honest look at how these athletes approach sport in the context of heart disease.  These stories are just very real.

At the end is a useful glossary of terms that will make the book more accessible and also a useful reference, or reading list.

The book is currently available in print form for $14.98 from Create Space.  Proceeds from the book will go to the Cardiac Athletes Trust Fund to support the organization’s charitable activities.

 

 

The Medical Toll at Endurance Events

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Have you wondered about the “medical toll” at endurance sports events?  By that, I mean the sum of all the medical problems that occur to atletes during their participation (and perhaps shortly afterwards as well).

It’s an interesting issue, with many practical implications.  If you’re organizing a swim meet, you’d be interested in the likelihood of drowning.  If you’re participating in a bicycle race, you’d be interested in the frequency of crash-related traumatic injuries.  If you’re the spouse of a long-distance runner, you’d be interested in the likelihood of heart-problems for the participants of a marathon.  Should your event have a “medical tent” to handle anticipated injuries or medical problems?  Where should the medical tent be located and how should it be staffed?  How should your local EMS system or hospital prepare to handle athlete-patients?  You get the idea.

Yet surprisingly little has been written in the medical and scientific literature about the medical toll of endurance events.  There’s probably a bunch of reasons, including the fact that nobody in particular’s keeping track.

This past week there was an interesting report in the British Medical Journal from a group of investigators in Cape Town, South Africa, and headed by Martin Schwellnus.  The report, “Medical complications and deaths in 21 and 56 km road race runners:  a 4-year prospective study in 65,865 runners–SAFER study I,” describes the “medical toll” at recent editions of the Two Oceans Marathon races.  The report and the findings caught my eye.

 

The Study

The participants in the study were the 65,865 runners who took part in either the 21 km half marathon or 56 km ultra marathon, the premier events at the Two Oceans Marathon races that are held each year in Cape Town, South Africa.  They focused on the 2008 through 2011 editions.  The weather conditions for these races was generally favorable, with temperatures ranging from 11.5 to 18.2 degress C and relative humidity ranging from 77% to 93%.

Like many long distance running events, these races had an elaborate set-up for provision of medical care on race day, including on-route medical stations, a dedicated medical facility at the finish, and designated hospitals where athlete-patients would be transferred should they need emergency care.  Because the system for medical care was so well proscribed, the investigators were able to compile a list of all “medical complications” that occured  in the race participants.

The investigators did not consider the most minor of medical complications, such as seeking medical attention at various first-aid stations for minor injuries or requiring physical therapy attention at the finish line.  For simplicity, “medical complication” was defined as an episode that required the attention of a doctor.  Exercise-associated muscle cramps alone were not considered a “medical complication” unless there were additional symptoms such as confusion, dizziness, nausea, or vomiting.  A serious medical complication was defined as a “medical complication that could result in death unless urgently diagnoses and treated.”  And finally, deaths were recorded as well.

 

The Results

Of the 65,865 participants, 64,420 (97.8%) finished their race(s).  The finishing rate was 99% for the 21 km races and 97% for the 56 km races.

Two deaths were documented, each in a 21 km race.  The fatality rate, then, was approximately 1 per 20,000 participants in the 21 km races.  There were no deaths in the 56 km races.

Overall, there were 545 medical complications among the 65,865 participants, a rate of approximately 0.8% (8.27 per 1000 participants).  The rate was approximately 0.5% for participants in the 21 km races and 1.3% for participants in the 56 km races.

Included in the 545 total medical complications were 37 that were designated as serious medical complications.  This is a rate of approximately 0.06% (0.56 per 1000 participants).  There was no significant difference in the overall rate of serious medical complications based on the distance of the race.  The serious life-threatening medical complications included:

  • Ischemic heart disease (including successful resuscitation from cardiac arrest), in 3 runners
  • Myocarditis, in 2 runners
  • Serious cardiac arrhythmias, in 2 runners
  • Symptomatic hyponatremia (low sodium), in 9 runners
  • Serious metabolic complications, in 5 runners
  • Serious heat-related disorders in 7 runners (1 with hypothermia, 6 with hyperthermia)
  • Pulmonary edema, in 2 runners
  • Serious fluid, electrolyte, or acid-base abnormalities, in 4 runners
  • Bronchospasm, in 2 runners
  • Convulsions, in 1 runner

Further statistical analysis was used to evaluate groups of medical complications, depending upon the body’s organ system that was involved.  In this analysis, the frequency of complications involving the cardiovascular, musculoskeletal, metabolic, gastrointestinal, and respiratory systems was greater among the 56 km runners than for the 21 km runners.

 

The Takehome Messages

The chances of a medical complication or serious medical complication were small, for both of the race distances.  Athletes should know, then, that these risks are small as they consider participation in an event.

Information like this should inform safety planning on the part of event directors, event medical directors, and events’ local medical communities.

I suspect that the results are generalizable to races outside of South Africa and also to the real-world question of half marathon vs. marathon races which would be typical distances in the United States.

It is a somewhat surprising finding that the only 2 deaths occurred in the shorter, 21 km races.  We know from recent detailed studies involving millions of runners that the risk of sudden cardiac arrest at long-distance running events is almost 3 times higher for marathon runners than for half marathon runners.  In this study, it’s a statistical oddity–that not enough years were considered to evaluate such a rare end point.

Intuitively, it is not surprising that there would be more medical complications in the longer events.  If nothing else, there is more “time exposure”–more athlete-hours spent in strenuous exercise.

I am surprised, though, that the frequency of serious, life-threatening, medical complications was similar for the 2 race distances, I would have guessed that these, too, would be more common in the longer distance races.  Perhaps the take home message is the converse–that a shorter race is not necessarily safer when it comes to life-threatening medical complications.  And the real world consequence would be that half marathoners not give short shrift to their health before participating.

Lastly, I’ll continue to hope that national governing bodies and large event organizers (eg, World Triathlon Corporation [WTC[) might collect and disseminate information about the “medical toll” at their races.  As a sporting community, we would all benefit.

Physical Activity Levels and Atrial Fibrillation

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In the medical news last week came another interesting report on the relationship between physical activity and atrial fibrillation (AF).  Reported in the medical journal, Heart, a team of investigators led by Nikola Drca from the Karolinska Institute in Stockholm gave us a study entitled “Atrial fibrillation is associated with different levels of physical activity levels at different ages in men.”  This is the largest-ever study of the relationship between physical activity and AF, so the findings and conclusions deserve our attention here in the athlete community.

To set the stage for our discussion, recall that AF is a fairly common arrhythmia that is generated in the upper chambers of the heart–the left and right atrium.  I’e written about AF here at the blog previously, in general terms for athletes.  We’ve known for a long time that AF is associated with some other types of heart disease, particularly heart valve disease, and increases in prevalence as we age.  The problem of AF is not benign.  For athletes, the arrhythmia disrupts training or competition, but over the long term there is a small but real risk of stroke and also the chance of harm to the heart itself.  Moreover, the available treatments–medications or ablation procedures–carry risk as well.

We also know that AF is associated with exercise.  We know from prospective, longitudinal population studies that long-time, regular exercisers are more likely to develop AF over the years.  And we know from targeted studies that athletes in the endurance sports are particularly at risk for developing AF.

Healthy endurance athletes should be asking the questions like:

  • What are my chances of developing AF?
  • How can I exercise safely and avoid developing AF?

Questions like these motivated the current study.  Let’s take a look….

The Study

The purpose of the study was to determine if there was an association between physical activity level and the development of new AF in middle-aged men.

Back in 1997-1998, the investigators contacted all of the men aged 45-70 years who were residing in 2 counties in central Sweden and asked them to participate.  About half (48,850 men, or 49%) responded by completing a questionnaire.  From these, several thousand were excluded from further study because of:  missing data on the questionnaire, death before the study’s follow-up period began, a current diagnosis of AF (1,496 men, or about 3% of the entire group), and the current diagnosis of some forms of cancer.  This left 44,410 men to be part of the study.  The average age of the participants at the time of enrollment was 60 years.

The questionnaire asked 2 questions about the amount of physical activity that the men engaged in.  They were asked to think back and to recall their activity levels at age 15, at age 30, at age 50, and at the current (“baseline”) time.  The participants younger than 50 years only answered for age 15 and for age 30 and “baseline.”  The questions were:

“How many hours per week do you engage in leisure-time exercise (such as running, soccer, bicycling, swimming, floorball, gymnastics, cross-country skiing, etc.)?”

The respondents had to choose between:

  • <1 hour
  • 1 hour
  • 2-3 hours
  • 4-5 hours
  • >5 hours.

“How much time each day do you spend walking or bicycling for everyday transportation purposes?”

The respondents had to choose between:

  • <20 min per day
  • 20-40 min per day
  • 40-60 min per day
  • >1 hour per day

In addition to the questions about physical activity, the respondents provided information about their medical history, smoking history, family medical history, medications, alcohol consumption, and level of education.

The respondents were then followed for 12 years to see what happened to them….and, in particular, to see if they developed AF.

The Results

At the end of the 12 years, there was an accumulated experience of 476,112 person-years!  And during that time, there were 4,568 new cases of AF.  Doing the math, that works out to 9.6 cases of AF per 1,000 person-years.  Put another way, of the 44,410 participants, about 10.3% developed AF.

But the goal of the study was to determine if the individuals’ activity level was related to their chance of developing AF.

The primary finding of the study was that the self-reported leisure-time exercise at age 30 was indeed associated with the risk of developing AF.  The investigators performed a statistical analysis designed to isolate the effect of the number of hours of exercise per week (and eliminating, as best possible, the effects of other influences on the risk of AF).  They showed that the risk of developing AF was 19% greater among the individual who exercised >5 hours per week (at age 30) compared to those who exercised <1 hour per week.  Remember that overall, 10.3% developed AF….so in terms of absolute risk difference between the extremes of exercise level reported at age 30, we’re talking about a couple percentage points different in the chances of developing AF.  It’s because of such a large number of participants that differences this small can be detected.

Another important finding of the study was that the self-reported leisure-time exercise at baseline (when participants enrolled in the study, at mean age 60 years) was not related to the development of AF.  And furthermore, the investigators found no relationship between the amount of self-reported leisure-time exercise at age 15 or at age 50 and the development of AF.  The only such relationship was for the activity level at age 30.

The last important finding of the study came from a subgroup analysis.  The participants who were at greatest risk of developing AF were those who reported >5 hours per week of leisure-time exercise at age 30….and <1 hour per week of leisure-time exercise at the time of enrollment in the study.  These individuals were 49% more likely to develop AF during the 12-year follow-up period than individuals who exercised <1 hour per week at both age 30 and at the time of enrollment in the study.

There was no relationship between the amount of walking/cycling for transportation purposes at any age and the development of AF.

The Take-home Messages

  • The current study adds to our knowledge about exercise and AF.  I hope that more studies are to come.
  • The relationship between exercise and AF is not completely understood and, indeed, the relationship may not be straightforward.  Studies like this one ask participants to recall and note their activity levels at just a few moments during their lifetime.  That can be hard to do, memory being what it is.  Undoubtedly, the risk for developing AF must be related to some sort of dose of exercise over time.  In retrospect, that’s hard to quantify.  People exercise more some years than others.  Some start exercising and some stop.  They start and stop different types of exercise.  I’ll bet that the intensity is important, too, yet how do we quantify this (in some straightforward way) so that analyses can be performed?
  • Previous studies, both in large longitudinal cohorts as well smaller invetigations of particular endurance athletes, have shown an increased risk of AF over the long term among individuals who exercised a lot.  This phenomenon has been shown best for individuals in young to middle age, and for men more so than women.  This relationship has been shown in enough different populations that we should accept it as fact.  The current study points out that the increased relative risk compared to non-exercisers may reflect a rather modest increase in absolute risk.  But that’s at odds with previous studies that have shown as much as a several-fold increased risk for AF among heavy exercisers.  But whatever the magnitude, that risk must be considered together with the other, well-established benefits of exercise over the long term when athletes are making decisions about their activity level.  Don’t forget that exercisers live longer.  That’s an important endpoint to keep in mind.
  • The current study is curious in at least one respect.  At first glance, it seems a bit odd that a relationship between exercise and development of AF could only be established for the amount of exercise reported at age 30…..and not at age 15, 50, or at the time of enrollment.  Why is that?  Could it be possible that we should exercise freely, with no worry about AF, while we’re young….and then again when we’re old?  Maybe the 30-year-olds exercise with greater intensity.  Maybe they accumulate more hours of exercise over more years.  Maybe they engage in different forms of exercise that carry more risk.  Perhaps “>5 hours” for the 30-year-olds was actually much more than 5 hours.  The current study doesn’t provide answers.  This needs to get sorted out with future studies.  We need to better define the safe dose of exercise with respect to AF.
  • Finally, why is exercise associated with AF?  In truth, we don’t know in any detail.  It seems that it must have something to do with the structure of the atrium that changes over years’ time with exercise.  The investigators note several of the potential reasons:  enlargement of the atrium, inflammatory changes in the atrium, and overdevelopment of the parasympathetic portion of the autonomic nervous system.  Perhaps all of these play a role.  I like Dr. John Mandrola’s blog post this week about this issue.  I like his take.

Related Posts

 1. Cyclist’s Account of Atrial Fibrillation

2. In the News:  Atrial Fibrillation in Cross Country Skiers

3. Atrial Fibrillation in Athletes (In a Nutshell)