A new research paper discusses how a standard cholesterol test failed an Ironman triathlete and revealed a hidden killer. Should endurance athletes request more than basic lipid checks?
A new study reveals that there may be benefits to more advanced lipid testing in triathletes. (Photo: Getty Images)
Published on March 31, 2026 at 06:00 AM
There are many reasons why people come to endurance sports. Some do it for the thrill of competition, others want to push themselves to accomplish things they never thought possible, and still many do it to find camaraderie with friends old and new within the endurance sports community. But the majority come for The health and wellness benefits of swimming, cycling and running.
However, improving fitness is not a magic solution. Yes, there is abundant evidence in the scientific literature that an active lifestyle improves the quality and duration of life, but there are also numerous examples of men and women at the peak of their athletic potential who have developed sudden and unexpected diseases, usually of a cardiovascular nature. These events are always tragic and cause understandable anxiety among those left behind. We wonder how this could happen to someone who was doing everything right?
Unexpected cardiac deaths in athletes
In the end, most of it is unexpected Heart disease and mortality In young athletes it is attributed to previously unrecognized genetic disorders.
Flo Hymana 1984 Olympic silver medalist in volleyball for the United States, died suddenly at age 31 of undiagnosed Marfan syndrome (a connective tissue disease that affects the heart and blood vessels).
Professional football player Christian Eriksen He suffered a heart attack during the UEFA Euro 2020 competition due to a hereditary heart rhythm disorder.
And of course a professional triathlete Tim O’Donnell had a heart attack during the race Due to a previously unknown genetic condition, it affected his lipid levels and led to premature coronary atherosclerosis (accumulation of fat and cholesterol in the arteries of the heart). As he said in Later interview with Triathlete“Know that fitness is not health… Just because we do Ironman doesn’t mean we are immortal.”
High risk and routine screening for elderly athletes
It’s not just younger professional athletes who are affected. As athletes age, the risk of heart disease also rises, but it can be more important for those who have a tendency to metabolic traits that lead to high cholesterol levels despite being active.
These individuals generally do not have any symptoms until their coronary arteries are significantly affected, after which they may only have a major event. For this reason, the American College of Cardiology and the American Heart Association recommend routine screening for men and women over 40, which includes a physical examination and lipid profile assessment (LDL, HDL, and cholesterol levels). Additional testing is recommended for those who have risk factors (such as smoking, a strong family history, or diabetes) or those whose initial examination is abnormal.
The Ironman case study questions the adequacy of screening
Recent paper It called into question whether standard health screening is appropriate for those who regularly train and compete in endurance sports. This study presented the case of a 55-year-old Ironman athlete who was previously asymptomatic but collapsed due to cardiac arrest during the bike portion of an Ironman race. Fortunately, the man was quickly resuscitated and recovered, and in the aftermath it emerged that he was known to have slightly elevated cholesterol levels inconsistent with the finding on his coronary angiogram that showed significant disease.
Doctors conducted additional tests, which revealed that the athlete had very high levels of… Small dense LDL particles (sdLDL) Although the level of LDL cholesterol is slightly increased. These sdLDL are He thinks it’s important In the development of coronary artery plaques (accumulation and blockage), but they are not routinely measured as part of screening.
The authors of this study suggest that this may need to be reconsidered. They argue, “This case underscores the challenges in assessing cardiovascular risk among endurance athletes. High levels of cardiorespiratory fitness, favorable lipid ratios, and the absence of traditional metabolic risk factors typically result in a low estimated risk of atherosclerotic cardiovascular disease, which may contribute to the under-recognition of progressive coronary artery disease until an acute event occurs. While endurance exercise confers significant cardiovascular benefit for most individuals, observational data suggest that coronary atherosclerosis can remain in some endurance athletes for life even when traditional risk measures appear to Favorable.
Small dense LDL and the argument for advanced testing
So, what do the study authors recommend as a way to address this risk? They believe that advanced lipid testing that measures sdLDL, among other types of specific tests not typically examined in basic lipid profiles, is indicated for some (but not all) middle-aged endurance athletes. The authors haven’t weighed in on who exactly these athletes are.
It is important to note here that this view is not universally shared. A Task Force From the American College of Cardiology, in collaboration with the American Heart Association, that although these markers are associated with cardiovascular outcomes, they are Similar performance and no improved risk reclassification Exceeds conventional fat standards.
Instead, Wider consensus It appears that these types of advanced lipid profiles should be reserved for athletes with a family history of premature cardiovascular disease or patients with known hypertriglyceridemia to identify genetic disorders.
Reassessing risk through essential lipid profiles in endurance athletes
Unfortunately, there is no precise answer on how to identify those most at risk Cardiac events Despite your participation in endurance sports, you may take solace in knowing that you are still less likely for something like this to happen when you are an endurance athlete than when you are not one.
In addition, baseline lipid analysis remains a very reasonable and accepted method for assessing 10-year disease risk in most cases.



