This month’s post will be a bit different from the norm. I will of course be sharing some thoughts as it relates to endurance sport-related science, but I will be using a recently published study as an opportunity to share some learning points about properly interpreting and contextualizing single research studies as this is an incredibly important skill for anyone that is utilizing research to inform a larger context of coaching athletes, including self-coaching.
I wanted to discuss the topic of long-term endurance exercise and its impact on cardiovascular health, or cardiovascular health risk to be more precise. I have come across more and more articles, podcasts, and social media pages delving into the hotly debated topic of chronic over-exercising and the risk it poses to cardiovascular health. “Over-exercising” in this context doesn’t even mean extremely excessive, over-the top, out-of-control compulsive exercise. It can simply refer to exercise that is above and beyond what is recommended for health and longevity and done so chronically (i.e., for decades to a lifetime).
For reference, current evidence-based physical activity guidelines for recommend ~150-300 min/week of moderate-intensity cardiovascular activity or ~75-150 min/week of vigorous-intensity cardiovascular activity in addition to two days/week of full-body strength training for maximum health benefits (5). The return on investment, so-to-speak, for one’s health starts to decline dramatically beyond this level of exercise. In other words, exercising longer and/or more vigorously does not necessarily confer any significant benefit to one’s health above what is garnered at the recommended levels.
Now, this does not mean that exercising more than the ~2.5-5 hours/week of exercise that is recommended for health is harmful to one’s health. However, there has been some interest among researchers and sports practitioners as to whether extremely high levels of endurance exercise for decades can lead to a small increase in cardiovascular health risk. There have been more and more cases of elite-level athletes experiencing sudden cardiac events and coronary events, or at least more that have been documented, and this has sparked research that aims to explore this area to a greater degree.
The research to date, as I will discuss a small sliver of next, is mixed and inconclusive. But this has not kept some who are on one extreme end of the fence or the other from duking it out in online spaces to convince the masses of their opinion. Some are hardcore believers that there is a substantial risk to one’s health if they engage in high levels (this is somewhat subjective and arbitrary at this point as there is no real hard cut-off or definition as to what “high levels” of exercise are) of endurance exercise over the course of their lifetime, while others believe that there is zero risk whatsoever.
Much like everything else in life, the answer probably lies somewhere in the middle. And from what I have surmised reading just some of this research is that there does seem to be the possibility of some very small risk of highly specific cardiovascular incidents occurring among endurance athletes that do engage in large volumes of endurance-specific exercise for decades upon decades of their life. However, this miniscule risk is likely far outweighed by the massive protective benefit that one receives from exercise.
Nonetheless, I find this area of research compelling as it is so new and something I want to be better informed on as an athlete myself and a coach for other athletes. If there are risks that are present, I want to know how to mitigate them. So, I thought it would be appropriate to dive into a single research study next that piqued my interest. I’ll then follow-up a discussion of this study with some learning opportunities related to contextualizing and interpreting research.
Lifelong endurance exercise and coronary atherosclerosis risk
De Bosscher and colleagues (1) published a study in 2023 that aimed to investigate the relationship between lifelong endurance exercise and coronary atherosclerosis risk (i.e., plaque development). For the purposes of this study, they enrolled 191 lifelong masters endurance athletes, 191 late-onset endurance athletes (endurance sports initiation after 30 years of age), and 176 health non-athletes. Lifelong endurance athletes had the highest coronary plaque scores across multiple different measurements of plaque (including calcified and non-calcified plaques).
However, the larger body of research literature still demonstrates that lifelong endurance athletes have an overall lower risk of plaque-related cardiovascular events (typically referred to as ischemic events) when compared against non-athletes (2-4,6). In some studies, the lowest risk of these types of events were in athletes with the highest coronary plaque scores (3,6). In other words, a higher presence of coronary plaque in lifelong endurance athletes does not seem to be related to a greater likelihood of ischemic events and is, in fact, quite the opposite. One would expect to see research demonstrating that lifelong endurance athletes suffer from a greater likelihood of ischemic events as plaque scores increase, but the research does not show this.
Contextualizing research and interpreting single research studies
I found the study discussed herein a rather interesting one, not only because of the findings, but because of how one’s contextualization of this study is so dependent on having a broader understanding of the larger body of research surrounding the topic. If all I did was share this single research study with another coach or fellow athlete, which has many limitations needing to be accounted for that influence the interpretation of the results, they may draw the seemingly logical conclusion that lifelong endurance exercise poses a risk to cardiovascular health. Yet, when one takes the next step and asks the question as to whether these elevated plaque scores are really related to a greater likelihood of cardiovascular events, the larger body of research shows this to not be true.
This is such a common problem in today’s media especially where attention-grabbing and click-bait headlines are based on single studies that are not put into the appropriate context. This happens over and over and over on multiple different platforms, people start to see it, and misinformation or poorly contextualized information starts to spread like wildfire.
It's easy to have a biased message to spread, go to Google Scholar, type in the keywords you want, and find a study that could be spun in a way to support a biased opinion. And so, alas, people do it all the time. This is why I always, always, always recommend getting information from trusted resources or individuals that are transparent in how they formulate their recommendations and advice (i.e., do a bit of homework to see what someone’s background, education, and credentials are as well as examine how they share information).
This is not to say that individuals who are well-versed in reading and interpreting research or whom are researchers themselves are know-it-alls or have the answer to every question. Those who seriously understand research and how it works are often the ones that will never say the phrases “science has proven”, “new proof that X works”, “do X for guaranteed results”, “Stop doing X and do Y”, and make other aggressive and inflammatory claims. These types of claims and phrases highlight that someone has a serious misunderstanding of how science works and how to interpret it, and/or that they are just pushing an opinion and not an evidence-based recommendation.
Research is a constantly evolving series of objective investigations that aims to better understand how things work. A research study does not necessarily seek to “prove” anything by its nature. A researcher/scientist simply aims to ask a question, formulate an objective method of isolating that which they want to better understand, and then conducting the study to draw a conclusion that helps us understand the answer to a question a bit better. And most often, science has proven very, very little. Science is a tool that can be used to vastly improve our understanding of best practices and best approaches. And when attempting to better understand big questions or problems, single research studies do not tell the whole story, they just contribute to it much like a single puzzle piece does not depict the whole picture.
Hopefully you found this somewhat out-of-the-norm post useful in a variety of ways. But at the very least, I hope you learned a bit more about the relationship between lifelong endurance exercise and cardiovascular health as well as something related to interpreting and contextualizing research. If you’re an athlete, keep training for your sport of choice without fear that you will be worse off in the future because of it. And if you are a coach or practitioner, keep trying to better understand and learn, study by study, bit by bit, and always be sure to put things into a greater context when formulating your advice and recommendations.
1. De Bosscher R, Dausin C, Claus P, Bogaert J, Dymarkowski S, Goetschalckx K, Ghekiere O, Van De Heyning CM, Van Herck P, Paelinck B, El Addouli H. Lifelong endurance exercise and its relation with coronary atherosclerosis. European Heart Journal, 2023.
2. DeFina LF, Radford NB, Barlow CE, Willis BL, Leonard D, Haskell WL, Farrell SW, Pavlovic A, Abel K, Berry JD, Khera A. Association of all-cause and cardiovascular mortality with high levels of physical activity and concurrent coronary artery calcification. JAMA cardiology. 2019 Feb 1;4(2):174-81.
3. Gao JW, Hao QY, Lu LY, Han JJ, Huang FF, Vuitton DA, Wang JF, Zhang SL, Liu PM. Associations of long-term physical activity trajectories with coronary artery calcium progression and cardiovascular disease events: results from the CARDIA study. British Journal of Sports Medicine. 2022 Aug 1;56(15):854-61.
4. German CA, Fanning J, Singleton MJ, Shapiro MD, Brubaker PH, Bertoni AG, Yeboah J. Physical Activity, Coronary Artery Calcium, and Cardiovascular Outcomes in the Multi-Ethnic Study of Atherosclerosis (MESA). Medicine and Science in Sports and Exercise. 2021 Dec 29.
5. Piercy KL, Troiano RP, Ballard RM, Carlson SA, Fulton JE, Galuska DA, George SM, Olson RD. The physical activity guidelines for Americans. Jama. 2018 Nov 20;320(19):2020-8.
6. Radford NB, DeFina LF, Leonard D, Barlow CE, Willis BL, Gibbons LW, Gilchrist SC, Khera A, Levine BD. Cardiorespiratory fitness, coronary artery calcium, and cardiovascular disease events in a cohort of generally healthy middle-age men: results from the Cooper Center Longitudinal Study. Circulation. 2018 May 1;137(18):1888-95.
Happy training and racing!
-Ryan Eckert, MS, CSCS
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