Issue: July 2017
July 14, 2017
18 min read

Care of Kona Ironman World Championship triathlon athletes requires preparation

Issue: July 2017
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Although far from being an endurance athlete, I have had the distinct pleasure of being a volunteer physician for the past few years at the Ironman World Championship, a triathlon held yearly in Kailua-Kona, Hawaii. I thought I would be most needed to address athletic hip conditions. However, I was placed in the unfamiliar role of a primary care provider, treating mainly volume-depleted athletes. Because I was working outside of my comfort zone, I was glad to learn two orthopedic surgeons, as well as a past president of the American College of Sports Medicine, were working alongside me.

Up until that time, my athletic experience took place long ago and was limited to sports with a ball, as a football running back. Humbled by my first Olympic triathlon performance (or lack thereof) several years ago, I have since gained great respect for endurance sports and the athletes who compete in them, especially at the world-class level. To that end, I have invited a faculty panel of three physicians (two past Ironman finishers) and one senior past Ironman finisher, to share their thoughts on the most common, severe and interesting conditions they have seen and treated in the elite triathlete.

Dean K. Matsuda, MD

Roundtable Participants

  • Dean Matsuda
  • Moderator

  • Dean K. Matsuda, MD
  • Marina del Ray, Calif.
  • Lou Briones
  • Lou Briones
  • Los Angeles
    Ironman World Championship, Fourth place in age group, 2012
  • William Douglas Hiller
  • William Douglas Hiller, MD
  • Evanston, Wy.
    Ironman World Championship finisher 1982, 1983, 1984
  • Thomas K. Miller
  • Thomas K. Miller, MD
  • Roanoke, Va.
    Ironman World Championship finisher 1996
  • Robert Sallis
  • Robert E. Sallis, MD, FAAFP, FACSM
  • Fontana, Calif.

Dean K. Matsuda, MD: What is the Ironman World Championship?

Thomas K. Miller, MD: The Ironman began in 1978 on the island of Oahu with 15 participants (12 finishers) facing event distances (ocean swim 2.4 miles, bike 112 miles and run 26.2 miles, in that sequence) determined by combining those of the Waikiki Rough Water Swim, Around-Oahu Bike Race and Honolulu Marathon into one continuous race. The event moved to the lava fields of the Big Island of Hawaii in 1981. It now has more than 2,000 participants including physically challenged athletes, who were added to the competition in 1997. The event is a true championship event. It requires qualification to gain one of the coveted entry slots through a top-place finish in selected races during the year preceding the October event.

William Douglas Hiller, MD: The Kona Ironman is the Mount Everest of endurance sports. It is estimated, at this time, perhaps 600,000 people have finished an Ironman distance race and millions of people participate in shorter races annually.

Matsuda: What are the most common conditions treated in the Ironman medical tent?

Miller: These are related to fluid and electrolyte disturbances: dehydration; gastrointestinal issues (nausea, vomiting, diarrhea); and cramping. These go hand-in-hand and usually resolve with gentle, limited hydration and occasional pharmacologic intervention. The days of massive volume fluid replacement are over. Now, we try to do just enough to address gross fluid imbalances and let things settle down on their own.

Thomas K. Miller, MD, in Ironman World Championship 1996
Thomas K. Miller, MD, is shown in the 26.2-mile running event of the Ironman World Championship in 1996.

Image: Miller TK

Hiller: Exhaustion, dehydration, nausea and vomiting, cramping, hyponatremia, road rash and blisters are most common. In the early years, there were no good data to guide our treatment of the athletes. After my second Ironman, I was a medical supervisor for the hyperbaric chambers at the University of Pennsylvania Institute for Environmental Medicine, which was funded or supported by the NIH, the Office of Naval Research, NASA and other entities. Mary O’Toole, Pam Douglas and I founded Labman Hawaii and with many bright friends, including Bob Laird, and one of the best human physiology labs on the planet, we began to do many of the first ever physiology studies of triathlon. We had the first publications on exercise-induced hyponatremia and cardiac fatigue, as well as the first publication on medical care for triathlon athletes. Our work was the basis for medical care at the U.S. Triathlon Series, for what are now the USA Triathlon (USAT), Ironman and International Triathlon races. Through Labman Hawaii, we did a series of studies, including the first report on exercise and hyponatremia. This allowed us to choose proper electrolytes for the IVs, and recommend post-race electrolyte intake for the athletes. The real challenge for medical volunteers lies in not getting complacent or shell shocked. At certain times in the evening, we may be seeing one new patient per minute in the tent. With the wide age range of athletes and the high “Kamikaze quotient,” we must be alert for people with cardiac events. We have, in fact, had two athletes who presented with bowel infarction.

Matsuda: What are the most severe or life-threatening conditions you have treated in these athletes?

Miller: Recognizing hyponatremia — the athlete with weight gain, disorientation, flat affect, hyper-reflexia and uncontrolled cramping — is crucial to allow early intervention. Similarly, the disoriented athlete who is not sweating and with core temps of 104° or greater requires immediate cooling (dunk tank), IV access and emergency department (ED) transport when core temp is decreased.

Robert E. Sallis, MD, FAAFP, FACSM: Hyponatremia is the most common life-threatening condition we see in the medical tent. We have also had the occasional heart attack, heat stroke and bowel infarction, as well as anaphylactic reactions after a jellyfish sting. Hyponatremia is most commonly seen. The symptoms include headache, weight gain, disorientation, flat affect and swelling in the hands and feet. Since this is most commonly caused by the over-drinking of hypotonic fluid (water or even sports drinks), it is critical these athletes not be given IV fluid because they often are already fluid-overloaded. We assess this by weighing athletes before the race and then again once they enter the medical tent. Intravenous fluid should not be given to athletes who have gained weight. In severe cases, where sodium is less than 125 mEq/L (normal is 135 mEq/L to 145 mEq/L), we will give a 3% hypertonic saline solution, which rapidly corrects the low sodium. Possible complications from low sodium include seizures, coma and even death from increased intracranial pressure and brainstem herniation. Most Ironman athletes with hyponatremia respond well to rest and fluid restriction until their kidneys filter off the excess free water and the sodium level normalizes. Although it is much less common, heat stroke is even more deadly when the diagnosis is missed and treatment is delayed. Classic symptoms include alteration in mental status, such as confusion or acting inappropriately, with a rectal temperature of 40°C (104°F) or greater. These athletes are often obtunded and may be sweating profusely or appear dry and hot to the touch. The key is early recognition and rapid cooling via ice water immersion up to their neck in a tub. We cool them until their rectal temperature measured with an indwelling rectal thermistor drops below 102°F or they start shivering. With early diagnosis and rapid cooling, athletes with heat stroke almost always survive without sequelae.


Matsuda: What orthopedic conditions are commonly seen at the Ironman event?

Hiller: We see a lot of scrapes, bumps and bruises. Most injuries come from the bike, as would be expected. Clavicle fractures are an annual event. I was the orthopedic surgeon for North Hawaii Community Hospital starting in 1996, so I did dual duty in the med tent and as an orthopedic surgeon. One of my favorite events was driving an orthopedic hand surgeon who wrecked his bike and had an open dislocation of his thumb at the interphalangeal joint. We had a great talk on the drive up to the hospital. He supervised the operation. An MRI of an athlete some years ago at the event demonstrated quadriceps rupture following a kick to the thigh in the swim segment.

Miller: In the early years, we saw classic overuse issues in the knee and shoulder and stress fractures. Now, the most common orthopedic issues are due to trauma. Occasionally from the swim, but mostly with cycling misadventures there are wrist and clavicle fractures, acromioclavicular separations. Surprisingly, some of these athletes come in to the tent for assessment and return to the race. Long bone fractures have been assessed on the course and then individuals were later transported to the hospital for definitive care.

Matsuda: How is evaluation and treatment performed in the Ironman medical tent? What resources are available?

Miller: The medical tent has in-take and screening, observation and acute intervention sections. Athletes presenting to the medical tent are triaged based on severity of symptoms and presenting complaints. Our most experienced providers work that station. All athletes have a chart generated based on their race entry medical information and are weighed to compare their post-race to immediate pre-race weight. Some of the athletes will require simple observation. Athletes with more severe problems will be assigned a treatment cot staffed by nursing personnel and physicians in a “pod,” which is under the supervision of a “charge doc.” The tent has electrocardiogram/rhythm strip, pulse oximeter and continuous core temperature capabilities; an on-site lab to check electrolytes, glucose, troponin levels; IV capability, including hypertonic saline; and an onsite “pharmacy.” Staffing is done by nurses, physicians and support personnel and an administrative person handles records, communication with the central race communications, pharmacy and supply, lab and supply runners. Athlete escorts transport collapsed athletes. The physician staff expertise covers the spectrum from ED, cardiology and pulmonary to primary care sports and orthopedics. There are van-based mobile aid stations on the course, which are staffed to allow assessment and, if needed, initial intervention and transport to the main medical tent.


Sallis: The Ironman medical tent is a well-oiled machine that is busy on race day and typically sees almost one-third of all competitors. Most athletes walk over to the tent on their own after they finish and are not feeling well. Some collapse and are carried in, brought in on stretcher or by ambulance or van. Every athlete brought to the tent is evaluated in an initial assessment done by a triage doctor who makes the decision whether the athlete just needs to put up his or her feet and rest in the “weak and dizzy” section or needs to come into the tent for a more formal evaluation. Because the hospital in Kona is about a 45-minute to 60-minute drive on race day, we try to manage everything we can in the tent. We are lucky to have a highly-experienced physicians who man the tent each year who have a variety of specialties and experiences. This has led to an amazingly high level of care and an insistence there be “zero mistakes” in the evaluation and care of these athletes.

Matsuda: How does one evaluate and treat the collapsed Ironman athlete?

Hiller: Elite athletes, like age-group athletes, generally collapse because they aggressively override their bodies’ red lines. Exhaustion, dehydration and hyponatremia are leading diagnoses. The approach to diagnosis is straight-forward: Obtain history from the athlete or, if necessary, from family members, EMTs or bystanders. Perform a physical examination, labs, EKG and use an IV, if necessary. Almost all elite athletes recover rapidly with rest and oral or IV fluids. Again, we had two elite athletes with infarcted bowels who both recovered and returned to racing.

Sallis: Assessment of the collapsed athlete should begin with a quick evaluation of the athlete’s level of consciousness. If the athlete is awake and alert, the cause of collapse is more likely to be benign. Those athletes with an altered level of consciousness should be assessed to determine whether advanced cardiac life support is needed. Vital signs, including temperature, heart rate and blood pressure should be measured as soon as possible. The point in the competition at which the athlete collapsed is a clue to the possible severity of the situation. Collapse that occurs after an athlete finishes a race is much less concerning than when collapse occurs before the finish line. Important history questions in the evaluation of the collapsed athlete include the amount and type of fluid ingested during the race, which provides clues to dehydration, hyponatremia or hypoglycemia; the amount of urine passed during the race because athletes with dehydration or hyponatremia will most likely not be urinating; vomiting or diarrhea predispose an athlete to dehydration; and insufficient carbohydrate ingested before and during the race can lead to hypoglycemia and a feeling of extreme fatigue, which is often referred to as bonking. The presence of symptoms, such as chest pain, palpitations, nausea, wheezing, etc., could be clues to an underlying medical condition that caused the collapse. Examination of the collapsed athlete should include continued monitoring of the vital signs. Heart rate and blood pressure should be measured both when the athlete is supine and erect. Orthostatic change, which is an increase in heart rate by 20 beats or a drop in systolic blood pressure (SBP) by 20 mm Hg or a drop in diastolic blood pressure by 10 mm Hg between the supine and standing positions, suggests there is significant volume depletion and dehydration. Keep in mind most endurance athletes have extremely low resting hearts rates, so a pulse of 80 bpm may represent a tachycardia. Any athlete with altered mental status should have his or her rectal temperature measured to rule out heat stroke. Measuring temperature in the ear or mouth does not give an accurate measure of core body temperature and should not be relied on to rule out heat stroke. A rectal temperature above 104°F (40°C) demands immediate cooling measures with ice water immersion.

William Douglas Hiller, MD, in 1982 Ironman World Championship
William Douglas Hiller, MD, an Ironman World Championship finisher in 1982, 1983 and 1984, is shown bicycling on the way down from Hawi, Hawaii, during the 1982 triathlon.

Image: Hiller WD

The patient’s state of hydration can be assessed by asking him or her about thirst and the ability to spit. Athletes who are dehydrated will be thirsty and when this is significant (>5%) they will have a difficult time producing spit. Also, skin turgor may be diminished in athletes with significant dehydration and the skin can feel doughy and may tent if pinched. Conversely, athletes who are over-hydrated may look and feel puffy. In severe cases of fluid-overload, pitting edema in the lower extremities may be noted. This is often associated with low sodium levels (hyponatremia). Measuring body weight before and after competition is a helpful gauge of fluid status. Significant weight loss of 2% to 5% suggests dehydration and weight gain suggests fluid overload.

Important laboratory evaluations for the collapsed athlete include blood glucose and sodium level measurements. Hyponatremia is the most common cause of severe collapse in the endurance athlete. The ability to measure sodium levels is critical in diagnosing this condition and helping to guide appropriate treatment. Most athletes collapse for benign reasons that include exhaustion, dehydration, postural hypotension, muscle cramps and various lower extremity orthopedic conditions. Findings suggestive of a benign cause of collapse include the following:

  1. athlete is conscious and alert;
  2. rectal temp less than 104°F (40°C) or greater than 95°F (35°C);
  3. SBP greater than 100; HR greater than 100;
  4. blood glucose 70 mg/dL to 180 mg/dL; Na 135 mEq/L to 148 mEq/L; and
  5. weight loss 0% to 5% of body weight.

The most common serious causes of collapse in the athlete include hyponatremia, hypoglycemia, heatstroke, cardiac arrest and other serious medical conditions, such as seizures, subarachnoid hemorrhage, diabetic coma, etc. Findings suggestive of a more serious cause of collapse include the following:

  1. Unconscious or altered mental status (confused, disoriented or aggressive);
  2. rectal temperature greater than 104°F (40°C) or less than 95°F (35°C);
  3. SBP less than 100; HR greater than 100;
  4. blood glucose less than 70 mg/dL or greater than 180 mg/dL; Na less than 130 mEq/L or greater than 148 mEq/L; and
  5. weight loss or gain greater than 10% (weight gain suggests fluid overload and risk for hyponatremia).

Matsuda: What conditions prevent optimal run performance during the Ironman event?


Miller: More than anything, hydration and caloric intake on the bike dictates run performance. High winds on the bike course, and these can be brutal, make fluid and fuel intake difficult and predict slower finishing times, as well as how many athletes require post-race care.

Hiller: High winds and high temperatures on the bike tend to impair the subsequent run. Winds on the race course are frequently in the range of 20 knots to 30 knots or more. The sun at the Tropic of Cancer sears the blacktop road and surrounding black lava deserts, which is a harsh prelude to a marathon run. Riders who start the run dehydrated are in for a long day because 2% total body fluid loss has been demonstrated to affect performance and athletes who are slower on the run and who gain weight are at risk for hyponatremia. There are individuals who lose large amounts of sodium in their sweat (think cystic fibrosis). High heat, high humidity and high exercise intensity combined with a high sweat rate of up to 4 L/hour at the extreme, with high sodium loss, can set up athletes for symptomatic hyponatremia. It is potentially devastating. Athletes should have a clear and objective understanding of their own fluid needs under all race conditions.

Matsuda: What are the current nutritional recommendations preceding and during the Ironman triathlon? We have heard about carbohydrate loading, but have things changed?

Sallis: Proper hydration and nutrition are critical to success in the Ironman race. The key ingredients for success are fluids and carbohydrates. The average endurance athlete burns about 80 g carbohydrate per hour and loses about 1 g sodium in the sweat with an average sweat of 1 liter per hour, but this varies widely. The athlete must try to meet these needs and can do so with a combination of water, sports drinks, energy bars, gels and salt tablets. Sports drinks typically contain 60 g carbohydrate and 1 g sodium per liter. Simply drinking one liter of a sports drink per hour may be right for some individuals. However, it is most important that athletes drink to replace sweat loss. To do this correctly, they should know their sweat rate. It can be estimated by measuring the nude weight before and after a 1-hour run-and-bike done at race pace and in environmental conditions similar to what they will be racing in. The difference in pre-race and post-race workout weight is a good estimate of the athlete’s hourly sweat loss. So, for every pound of sweat lost, the Ironman athlete must replace 16 oz. of fluid. It is critical for most endurance athletes to drink on a schedule and attempt to match fluid intake with sweat loss to avoid dehydration, which can affect performance and health.


Some athletes choose to carbohydrate load by avoiding carbs for a week or so before the race only to load up the night before the race, which can cause bloating and other side effects and is not used much anymore. Instead, athletes should consume a balanced meal the night before the race that consists of carbs and low protein from foods they like and they know from experience sit well with them. It is then advisable for endurance athletes to start the race fueled by a high carbohydrate meal consumed 3 hours to 4 hours prior to the race. They should also start the race hydrated, but not overhydrated, with the stomach comfortably full. It is imperative they know their sweat rate and drink on a schedule they establish during training runs and rides, such as every 15 minutes. After the race, they should refuel quickly using snacks that contain both carbohydrate and protein, as well with fluids and electrolytes, such as chocolate milk or a peanut butter and jelly sandwich.

Matsuda: Is there scientific support for specific training regimens for Ironman athletes that can aid performance and perhaps decrease race day injuries?

Hiller: Measure and know your fluid losses. Know exactly how much, what and when you will be consuming fluid and nutrients. Never change things on race day. Get to your race as many days or weeks before the race as possible. Stick to your own plan.

Sallis: Doing an Ironman is not for everybody. However, triathlon is a great sport that, by nature, requires participants to cross-train. For that reason, I often recommend it to patients who love endurance sports, but are struggling with recurring overuse injuries related to constant running, cycling or swimming. I generally recommend patients start with a shorter triathlon event, maybe a sprint or Olympic distance event. If they are committed and have the time, then it would be reasonable to set their sights on an Ironman distance event. Training should begin at least 6 months before the event and include several run, bike and swim sessions each week. This will take a lot of time, which may be a problem at work or home, so athletes should make sure they have buy-in from the important people in their lives before they decide to sign up. For a first Ironman event, I suggest the goal be simply to finish without illness or injury. After that, it may be reasonable to think about training to compete in a particular age group. There are numerous online training programs. I would recommend having an experienced coach help with advice.


Of all the Ironman races, Kona is distinctive because of the harsh environmental conditions. The combination of heat and humidity make it the toughest Ironman on the planet. Qualifying for the Kona Ironman means you are among the top Ironman triathletes in the world, but it is extremely difficult. Athletes can also get into the race by lottery, but they still must complete an Ironman distance event to qualify. Either way, athletes get to share the day and the course with the pros and hear that incredible proclamation upon finishing: You are an Ironman.

Matsuda: Does cardiac screening of elite athletes help prevent major cardiac events?

Miller: I think the first issue for mature athletes is to recognize that participation in endurance sports does not mean immunity from cardiac issues. If questions exist due to family history or individual cardiac risk factors of hypertension, elevated lipids or diabetes, then cardiac assessment is prudent. Second, if there are symptoms of rhythm disturbances, such as dropped beats, irregular rhythm or tachycardia with workouts, cardiac evaluation should be done before continued training or event participation.

Sallis: There is little evidence that routine screening of asymptomatic athletes with either EKG, treadmill or echocardiogram is effective in reducing the risk of exercise-related cardiovascular events. There is also a lack of consensus regarding the extent of medical evaluation needed as part of the exercise preparticipation health screening process in otherwise healthy individuals. The U.S. Preventive Services Task Force found screening exercise testing had no value in low-risk asymptomatic adults and found insufficient evidence for or against exercise testing in the preparticipation assessment for structured exercise in subjects at higher risk. For that reason, it is not a requirement for Ironman triathletes to undergo cardiac screening prior to competing. However, athletes with symptoms or strong risk factors should be considered for cardiac screening.

Matsuda: How long have you been volunteering as a medical provider at the Ironman and what is your single best tip for doing that?

Miller: I have been volunteering since 1989. I started out weighing athletes as part of a Labman Hawaii research project. When providing care, remember the participants are well-trained and for the most part will equilibrate and require minimal intervention. The challenge is to recognize the few who have the potential to go bad. I believe we have gotten better at that over the years. When volunteering, remember it is a long day and to hydrate and use sunscreen.


Hiller: We did our first Labman Hawaii study in Kona in 1984 and I have been involved in the medical tent ever since. I have served as research coordinator, assistant medical director, chief physician and medical director for Ironman. I have also been a medical official for 24 International Triathlon Union World Championships, was on the Competition Jury for the Olympics in Sydney in 2000, Chief Medical Officer for the Olympics in Athens in 2004 and for the Olympics in Beijing in 2008. I was also the medical delegate for the Paralympic Games in Rio de Janeiro in 2016. My best tip for the medical tent is to be a thoughtful physician. Get history, physical, labs as needed, and do not be shy about asking questions of more experienced physicians. Also, never leave the medical tent before 1:00 a.m.

Sallis: I have been working in the medical tent since 1994 and serve as the chair of the Ironman Sports Medicine Conference. My best tip for evaluating an athlete in the medical tent is to always start with the basics. A good history and physical exam will usually always guide you the diagnosis and appropriate treatment. Most athletes get better by simply elevating their feet, being allowed to rest and by taking oral fluids.

Matsuda: As a senior endurance athlete, tell us about your experience as an Ironman athlete and how your workouts have evolved over the years?

Lou Briones: I started bike racing in my mid-twenties and began to run 5Ks and 10Ks in my thirties. I had some talent in both disciplines, placing top-10 many times. Finally, I learned to swim at age 44. There was not much talent there, but combined with bike and run I became a good triathlete. I did a lot of research at the library to learn all I could about training methods in all three disciplines and I raced in each individual discipline. When I first started training for Ironman, my focus was on endurance. I simply wanted to be certain I could do the distance in the swim, bike and run. I trained 20-hours a week, mixing two 1-hour workouts every day Monday to Friday; doing a long bike ride on Saturdays of 4 hours to 6 hours; doing a 1-mile to 2-mile ocean swim on Sunday, followed by a gradually increasing long run in the afternoon on Sunday, building up to 20 miles. I intentionally did those runs in the afternoon when the sun was at its hottest because that coincided with the time I would be running in the triathlon. I did mostly shorter triathlons between 2001 and 2007. In 2008, I won my age group at Ironman Coeur d’Alene thereby getting the single slot to the Ironman World Championship in Kona. I qualified twice more and in 2012 I finished in fourth place (awards are presented to the top five). As I aged, my training included more recovery time between hard sessions. I took days off when I did not feel recovered. I did more fast, short workouts since I believed I had plenty of endurance already. By monitoring my fitness closely, I have been able to race at a high level within my age group (I am 69 years old chronologically, and will become 70 years old in October. But, based on the USAT competition rules, I turned 70 years old on January 1, 2017).


Matsuda: How does one volunteer for the medical tent?

Sallis: Each year a sports medicine symposium is held the week before the race which attracts more than 200 physicians to Kona, most of whom stay to volunteer in the medical tent. In addition to covering a wide variety of cutting-edge sports medicine topics, the conference also prepares attendees to work in the medical tent. CME credit can be obtained for this mini-internship medical tent experience. More information on the Ironman Sports Medicine Conference can be found at Go to the Ironman website to sign up to be a medical tent volunteer.

Disclosures: Briones, Hiller, Miller and Sallis report no relevant financial disclosures. Matsuda reports he receives royalties for intellectual property from ArthroCare, Smith & Nephew and Zimmer Biomet; is a paid consultant for Zimmer Biomet; and is an educational committee member of the International Society for Hip Arthroscopy.