Endurance Sports and Heart Health (Part I): Are Triathlons Dangerous?

This is the first part in a series of posts on endurance sports and heart health. 

About a year ago I decided to make the jump into triathlon. After playing soccer my entire life, including in college, I took up running as a way to fill the competitive void left. I was always one of the most fit players, often finding a sense of enjoyment from strength and conditioning sessions. I drew my enjoyment from others' dread.

300 yard shuttles or 1-mile intervals on the track- let's do it. Agility ladder - I'll go faster and harder than you can. Squats, deadlifts, and box jumps - sounds like a fun off-season to me.

Soccer introduced me to the methodical - and sometimes regimented - approach to training. Finding my own weaknesses and then relentlessly working to improve them. When it came to conditioning and fitness drills, I always wanted to go longer, faster, and harder than anyone else. More was always better.

So when it came time to step away from soccer, I needed something where I could try and go longer, faster and harder. Distance running seemed like a great fit and in 2007 I trained for and completed the Philadelphia Marathon. My training approach was what I had come to know - more was always better. I logged a lot of miles.

Today my training approach quite different - more is better up to a point; quality always trumps quantity; and recovery is the most important part of training.

So what happened?

It wasn't until a couple years ago when I began to understand some of the serious health risks of endurance sports. Research continued to emerge looking at the effects of excessive and long-term exercise on the heart, and particularly the cardiac remodeling that takes place as a result of years of running, biking or other aerobic activities. One major effect is something called hypertrophic cardiomyopathy - essentially a thickening of some parts of the heart muscle, which in turn makes it harder for blood to leave the heart. The heart must work harder. So, during an endurance event, when the demands of the heart are high, if an individual suffers from hypertrophic cardiomyopathy (or if their heart has remodelled after years of endurance exercise and stress), there is a risk of adverse cardiac events, like cardiac arrest, which result from blood vessel constriction. This article is a great overview.

Marathons and triathlons demand a lot of the heart, both over time and in short bursts. In triathlons, for example, the heart must quickly adjust when the body starts swimming from a virtual stand-still, often at a demanding pace and sometimes amongst some 2,000 other swimmings (watch the swim-start of Ironman Hawaii if you want a visual of how this looks). 

Stories about sudden cardiac events in marathoners and triathletes continue to make headlines. "Runner dies near finish of Chicago Marathon." "Shadows Over Ironman, but a Spirit of Carrying On." "Ironman death stuns athletes." With a seemingly increasing prevalence of such events, more research is now going into the issue, including by USA Triathlon.

USA Triathlon Fatalities Incidents Study 

To the credit of USA Triathlon - the national governing body for the sport in the U.S. - they recently commissioned a Medical Review Panel study to look at deaths during USAT-sanctioned events from 2003 to 2011. Preliminary findings were shared with a review panel in January of this year and the final report was published on the USAT website last week. Regardless of the study's limitations (some I discuss below), it has certainly generated a fair bit of discussion within the triathlon community.

Between 2006 and 2011, the study found an average of one death per every 76,000 participants, or about 1.4 per every 100,000 participants. For comparability, a study published earlier this year in the prestigious New England Journal of Medicine found roughly 1.25 cardiac arrests per every 100,000 participants in marathons and half-marathons held in the U.S.

Here are a few conclusions that can be drawn: 

• The number of USAT-sanctioned events, number of members and participation in USAT-sanctioned events have all steadily increased over the past several years. 
• The study didn't show any particular trends related to overall number of fatalities or fatalities per 100,000 participants.
• The majority of fatalities occurred during the swim portion of the triathlon (31 of the 45 total), and in varied race lengths, swim venues (e.g., ocean vs. lake), or method of swim start (e.g., mass start, wave, or time trial). Cardiac arrest was described as the immediate cause of death.
• The largest number of fatalities occurred in participants ages 40-49, with the 50-59 age group in a close second.

Summary of USAT Events, Participation and Fatalities

 



A few things the study did not show: 

• The study didn't exclusively look at USAT-sactioned adult triathlon races, but rather, it also included a variety of other activities sanctioned by USAT, such as camps, clinics, or short youth events. Nonetheless, the number of fatalities is still relatively small and there doesn't appear to any increasing trends. The perception of an increasing trend might simply be due to increased media coverage of the sport.
• The study didn't include all entrants. Instead, participation numbers do not include the number of individuals who dropped out of races without finishing. If the study considered all entrants, the prevalence of fatalities would have been even lower.
• Lastly, and most importantly, the study says nothing about context of the fatalities. What was the temperature of the water? What were the weather conditions? Did the athlete use a wetsuit? What were the medical resources available at the event? How experienced were the athletes who died? What was their medical history? 

Many of these contextual pieces of information could help draw far more useful conclusions about the reason for the fatalities. Most fatalities occurred in athletes of middle age (40s and 50s), were they life-long endurance athletes who maybe were experiencing the type of cardiac remodeling discussed above, which increases risk for sudden cardiac events (cardiac arrest was described as the immediate cause of death in 31 of the deaths)? Was their life filled with the added stresses of work, kids, the economy, etc., which puts additional strain on the heart?

Despite leaving a variety of gaps and drawing only minimal conclusions (a critique of some who say USAT was simply covering their bases to avoid claims of negligence rather than trying to draw any meaningful conclusions), the study does add to the overall conversation about addressing sudden cardiac events in endurance athletes. There is still a lot to learn. Post your comments below.
   

Food for Thought on Food Day

Yesterday was Food Day, a "nationwide celebration and a movement toward more healthy, affordable, and sustainable food." Started by the Center for Science in the Public Interest, the initiative has an impressive and fairly diverse listing of partner organizations, which include public health organizations like the American Public Health Association, activist groups such as Jamie Oliver's Food Revolution, and trade associations, including the Organic Trade Association.

Thousands of events were held across the country under the initiative, all devoted to highlighting five priorities in healthy diets, sustainable agriculture, reducing hunger, and protecting the environment and workers' rights.

Regardless of political leanings or views about the individual organizations associated with Food Day, the multidimensional emphasis is a useful way to think about the challenges of today's food system (and the one we envision for the future). Not only are there individual decision-making forces at play, there are even greater societal and systemic forces that effect everything thing from food production and availability, to the policies and guidelines set by governments and promoted to consumers.

 

Five Thoughts on Today's Food Challenges

• Data - The nutrition field includes a lot of murky data that relies often on associations and correlations rather than causality. This challenge dates back to some of the early research on diet and nutrition from the 1950's, but nonetheless is now the foundation for much of the current dietary guidelines and recommendations. If you're interested in diving deeper, Dr. Peter Attia, founder of the new Nutrition Science Initiative, provides an interesting overview of some of the history, and his organization has an incredible review of the literature to date (both a summary and citations). On a broader level and as obesity, heart disease, and other chronic diseases become increasing prevalent globally, many countries, particularly low-income countries, data systems "remain weak" according to the World Health Organization, and there is a "vital need" to improve them. If we're going to make evidence-based policies, we need to understand the science and epidemiology of nutrition, obesity, and chronic disease - and this means data.

On one of the main streets in Guhlshan, Dhaka, Bangladesh.

• Demographics - More than half the world's population reside in cities. By 2035, all regions will have reached the 50% urbanization threshold. How will food systems change? How must they adapt? A popular trend in the U.S. has been farmer's markets, which increased from 1,755 in 1994 to 7,864 in 2012, according to USDA data. Such markets provide urban dwellers the opportunity to purchase fresh produce and meats. However access is often inequitable, and scalability is a major constraint. Accessing nutritious food is of particular concern as cities continue to grow globally, and more people are concentrated in informal settlements, or slums. Research shows a high prevalence of chronic disease risk factors among the poor, such as this study from Soweto, South Africa, where 60% had more than one heart disease risk factor, 44% were obese, and 56% had hypertension. Research from a Brazil slum show similar trends, particularly with women. Among women 20-60 years old, 29% were overweight and 17% were obese.

• Diet - I like to think of diet not as an intermittent activity, but rather a lifestyle. And diet composition is just as important as overall energy (i.e. calories). Not all food is created equal. For example, not all beef is equal (e.g., grass-fed versus beef raised on a grain diet), which impacts, among other things, the ratio of omega 3/omega 6 fatty acid ratio in the beef. The latter of which the average person consumes way too much of, and prompts the body to do things like store fat rather than burn it. A similar story can be told for eggs, and many other products. In addition, some types of food today are quite different in genetic make-up than their ancestors of a 50-100 years ago - wheat being a big one - which is associated with a variety of health issues, and the nutrient quality found in many fruits and vegetables has declined over the last century as well.

• Dollars - healthy eating does not have to come at the expense of your wallet. A recent study by the USDA highlighted this precise point. It found that "for all metrics except the price of food energy, the authors find that healthy foods cost less than less healthy foods." In other words, if you evaluate based on edible weight (rather than cost per calorie) vegetables, fruit, and dairy foods were found to be less expensive than most "protein foods, and foods high in saturated fat, added sugars, and/or sodium." What's most promising is that there are emerging some practical solutions, like the tech start-up Zipongo, which is trying to make healthier choices the easier choice through a web-based health community and iPhone app, which "essentially combines the best of Mint.com and Groupon to create a service that gives users their own personalized wellness plans (and the ability to manage them), while offering discounts at the grocery stores they shop at the most."

• Difference - as in, make a difference. If nothing else, Food Day is a testament to the power of civil society and organizing. Food is one of, if not, the most important way to invest in your own health. Understanding the importance of food, what's in it, where it comes from, and how to prepare it can be an extremely empowering way for individuals to control their own health. Challenge yourself by filling your cart with real, whole foods next time you're at the grocery store (things like vegetables, seafood, meats (like grass-fed beef and free-range poultry), nuts, and fruit. Support efforts to teach children about food preparation and nutrition, such as home economics classes in schools, which are being cut. And lastly, learn, investigate, and challenge the "conventional wisdom." The newspaper headline or short soundbite on the radio may not be the entire story.

What are your thoughts on today's most pressing food issues. Leave a comment.