This is the 2nd part of a question that I split in two parts from Jamie – thanks for the great questions!
To give a larger context to the question: Jamie asks if there is a way to balance cardiovascular benefit and overall health benefit with the possible concerns of orthopedic problems from running. He also notes that some physicians have shared that running more than 2.5 miles in a day has no cardiovascular benefit and is harmful to joints.
In review from the last post here, there are no general orthopedic concerns from running. The assumption that “running is bad for your joints” is simply incorrect and not research-supported. If anything, it is contradicted by the research. But enough on that soap box …
One relatively consistent assumption about running has always been that it is good for your heart. And this is a good and well-supported assumption. Running (and other forms of cardiovascular exercise) have been shown to be beneficial for our bodies in a myriad of ways – decreased blood pressure, improved resting heart rate, improved efficiency of our cardiovascular system, improved respiration, stress hormone decrease, growth hormone increase, etc. A friend of mine who owns a running store has a sign that sites 98 benefits of running (and that’s not even all of them).
All that being said, is there such a thing as too much running being bad for your heart???
For a long time, this question was somewhat dismissed, but more recently it has come into light and even warranted Alex Hutchinson from Runner’s World addressing it here in a relatively recent article. This article also has references to multiple studies that I won’t repost here.
The first “new” finding from these studies is that “chronic long distance running” – in these studies somewhat loosely defined as completing multiple marathons per year over multiple years – can lead to increased artery plaque development compared to those not completing “chronic long distance running”. At first, this warrants having an alarm raised for those of us who choose to run marathon-length distances multiple times a year. And it is likely something that should at least be taken as a caution. In spite of this increased plaque, researchers indicate that the plaque formed in runners is often a more stable plaque than that formed from other things such as cholesterol, fat deposits, smoking, etc.
The likely explanation of this is that running places a stress on your blood vessel system. Our blood vessels are, in part, made of smooth muscle that is meant to easily expand with increased blood volume/pressure coming through. In exercise, this occurs regularly and can lead to improved pliability and efficiency in pumping our blood. With these study results, it seems that too much exercise can somewhat over-stress that system, which can lead to plaque deposits along the vessels. Certainly, over the long term, this over-stressing could lead to more and more build up as noted in the recent studies.
In spite of those findings, there were several runners in the “chronic long distance running” group that didn’t have any plaque build up at all, which indicates that other factors are playing a role. Diet, smoking, genetics, stress, etc. all come to mind as possible contributors. This means that we can in no way say that “chronic long distance running” causes plaque build up. It is simply an observation of a correlation right now. It could be that other factors are more/less responsible for the plaque build-up seen in runners.
An editorial by two sports cardiologists in the journal Circulation cites this as a major take-home point of the studies. They also discuss that higher plaque levels in sedentary population is considered a risk factor; however, they can not definitely state that higher plaque levels in active population is also a risk factor (this has not yet been isolated to study). Aaron Baggish and Ben Levine, the two cardiologists, indicate that these articles have not led to them telling runners to stop or decrease running; instead, they share the findings and make a holistic recommendation based on the individuals (i.e. maybe diet change, medications, etc.).
I recently spoke at and attended the Norton Sports Symposium and was on a panel of running specialists. Dr. Ryan Modlinski of Norton Healthcare spoke on cardiovascular concerns at this meeting and reflected on these recent findings and others. He expanded the conversation to include adverse cardiac events in endurance athletes. Research in these areas (running, cycling, skiing, triathletes, etc.) has also indicated that “chronic long distance athletes” might have an increased risk of cardiovascular event than more moderate-distance athletes and even sedentary individuals; HOWEVER, these have only been observed as correlations, not causation. Furthermore, the increased risk does seem to only possibly be present with those who are completing marathon-type distances over and over throughout the years and over multiple years. Personally, I would again reflect on the likely scenario that other risk factors could be playing a much larger role (i.e. eating terribly and working 70 hour weeks and THEN running a 50 mile event might be the issue vs. just running a 50 mile event).
To address the statement of “there are no cardiovascular benefits to more than 2.5 miles of running, and it likely does harm to joints”. This is undoubtedly false and there are piles of research that would refute it. I’m sure that your healthcare provider is just misinformed and meant no harm by this; unfortunately, we healthcare providers are as prone to believing misinformation as anyone. In fact, I would guess >50% of healthcare providers believe that running is bad for your joints in spite of the fact that there has never been any definitive research indicating that and plenty of research to refute it.
Running does benefit your cardiovascular system above 2.5 miles. In fact, some of the greatest cardiovascular benefits come from running greater than 80-100 minutes. This leads to changes in how the body rebuilds its circulatory system and improves oxygen processing along with multiple other positive changes that aren’t realized in shorter runs. This doesn’t mean that every run should be 80+ minutes, but it certainly can have some benefits to include those longer runs.
To sum up this line of questioning:
- Running is healthy for your joints and healthy for your heart
- It is likely that a very large amount of running (multiple marathons/year, multiple years) could contribute to some heart-related illnesses in runners; however, it is most likely these are in conjunction with other risk factors such as nutrition, stress, smoking, genetics, etc.
- Running longer than 2.5 miles does indeed have cardiovascular benefits beyond those of shorter runs
Hope that helps!
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