Study: Marathoners have more artery plaque

RationalActor wrote:

You always have to take correlative studies with a huge grain of salt, because the presence and interaction of confounding factors is so strong, especially in a system as complex as the human body, especially over so long a period of time.

For these types of studies, to make them meaningful, you really want to see a large and diverse sample size, so that you can screen out the confounders. You also want to select your criteria for inclusion carefully, so that you are limiting to one variable as much as possible.

That said, some of the methodology in the study seems really strange to me (which is not to say the results are invalid, but just that I'd like to learn more) such as:

1. The metric chosen for the exercise group is "has run one marathon a year for 25 years". This tells us little about the subject's exercise habits. An earlier study showed that marathoners had detrimental heart changes after the marathon, but further inquiry showed this was really only true in any lasting sense for marathoners who were improperly trained for the distance. At any given marathon, probably 85-90% of runners are improperly trained for the distance. If you have someone who has averaged 20 mpw run 26.2 at full effort for 4+ hours and later find it's bad for their hearts and circulatory systems, I guess that doesn't surprise me. There's a good chance many of these guys in the study ran the same marathon every year for 25 years because it had become a "thing" and a "streak" and they probably weren't very ready for it every year. That's going to take a toll. If we knew their average mpw, or even finishing times, that would be useful.

2. More than 1/2 these guys had a history of smoking, compared to 39% of the control group. Smoking is so toxic and affects so many systems that it can't be equalized well by statistical means, especially when we have no idea how much they smoked or for how long. It also raises the possibility that these guys used running to balance out some vices, which is not at all uncommon, which leads me to...

3. Diet. As someone above noted, we don't have data here on diets. The "furnace is so hot it will burn anything" concept reigned supreme for a long period of time, so it's impossible to know how that factors in.

So, the study's proven conclusion is:

A very small sample size of men (52% of whom have a history of smoking and about whose diet and lifestyle we have no data) who have run one marathon a year for 25 years (training volume and intensity unknown) have one slightly increased risk factor for heart disease (while also having multiple lowered risk factors as compared to the control - BMI, resting heart rate, hypertension rates).

I'm not sure how much value this has for the average letsrunner.

If you could show me a diverse and robust sample of well-trained runners without a smoking history, who followed solid diets and nonetheless had elevated plaque levels, then I'd pay much closer attention. Although even then, you'd have to show that the accumulation of that plaque was a net negative serious enough to outweigh the heart protective benefits of the exercise, which seems doubtful.

read this one. wrote:

RationalActor wrote:

You always have to take correlative studies with a huge grain of salt, because the presence and interaction of confounding factors is so strong, especially in a system as complex as the human body, especially over so long a period of time.

For these types of studies, to make them meaningful, you really want to see a large and diverse sample size, so that you can screen out the confounders. You also want to select your criteria for inclusion carefully, so that you are limiting to one variable as much as possible.

That said, some of the methodology in the study seems really strange to me (which is not to say the results are invalid, but just that I'd like to learn more) such as:

1. The metric chosen for the exercise group is "has run one marathon a year for 25 years". This tells us little about the subject's exercise habits. An earlier study showed that marathoners had detrimental heart changes after the marathon, but further inquiry showed this was really only true in any lasting sense for marathoners who were improperly trained for the distance. At any given marathon, probably 85-90% of runners are improperly trained for the distance. If you have someone who has averaged 20 mpw run 26.2 at full effort for 4+ hours and later find it's bad for their hearts and circulatory systems, I guess that doesn't surprise me. There's a good chance many of these guys in the study ran the same marathon every year for 25 years because it had become a "thing" and a "streak" and they probably weren't very ready for it every year. That's going to take a toll. If we knew their average mpw, or even finishing times, that would be useful.

2. More than 1/2 these guys had a history of smoking, compared to 39% of the control group. Smoking is so toxic and affects so many systems that it can't be equalized well by statistical means, especially when we have no idea how much they smoked or for how long. It also raises the possibility that these guys used running to balance out some vices, which is not at all uncommon, which leads me to...

3. Diet. As someone above noted, we don't have data here on diets. The "furnace is so hot it will burn anything" concept reigned supreme for a long period of time, so it's impossible to know how that factors in.

So, the study's proven conclusion is:

A very small sample size of men (52% of whom have a history of smoking and about whose diet and lifestyle we have no data) who have run one marathon a year for 25 years (training volume and intensity unknown) have one slightly increased risk factor for heart disease (while also having multiple lowered risk factors as compared to the control - BMI, resting heart rate, hypertension rates).

I'm not sure how much value this has for the average letsrunner.

If you could show me a diverse and robust sample of well-trained runners without a smoking history, who followed solid diets and nonetheless had elevated plaque levels, then I'd pay much closer attention. Although even then, you'd have to show that the accumulation of that plaque was a net negative serious enough to outweigh the heart protective benefits of the exercise, which seems doubtful.

I think this has been the most thoughtful post in the thread. thanks.

Tyrannosaurus Rexing wrote:

say whattt??? wrote:

Hmmm, we all know...or should know, that the increased O2 used with running leads to free radicals. We should also know that oxidation of polyunsaturated FA's causes increased cholesterol deposits. This is further complicated by prolonged exposure to high blood pressure during exercise which can damage blood vessel walls allowing the oxidized FA's to stick to the artery walls. This is not surprising at all. You all can deny it if you want to, or say the study is crap, but you will be ignoring reality.

You're funny. "we all know or should know" ?? Oh really? You know, based on your brilliant assessment of what causes CVD, I am going to stop exercising completely and never take a deep breath (want to limit as much of that evil oxygen from getting inside me) and never eat fish again, because if that oxygen mixes with those PUFA's from fish....bam! Ima dead man!

The studies showing the benefits of exercise on health are endless. Yes, at some point the negative benefits of the stress may outweigh the positive, but your conclusion that lots of running is SURELY bad for you is a joke not backed up by science.

Moderately hard aerobic exercise brings about:

Improved insulin sensitivity, raises HDL, can lower total/ldl cholesterol, lowers body weight, and lowers blood pressure and resting heart rate, ALL linked to improved health.

Two of the strongest predictors of mortality are how hard you can work on an exercise test, and how low your resting heart rate is. BOTH of these are strongly linked to regular, hard endurance exercise.

Exercise Capacity and Mortality in Older Men A 20-Year Follow-Up Study

Methods and Results—Between 1986 and 2008, we assessed the association between exercise capacity and all-cause

mortality in 5314 male veterans aged 65 to 92 years (mean􏰔SD, 71.4􏰔5.0 years) who completed an exercise test at the Veterans Affairs Medical Centers in Washington, DC, and Palo Alto, Calif. We established fitness categories based on peak metabolic equivalents (METs) achieved. During a median 8.1 years of follow-up (range, 0.1 to 25.3), there were 2137 deaths. Baseline exercise capacity was 6.3􏰔2.4 METs among survivors and 5.3􏰔2.0 METs in those who died (P􏰌0.001) and emerged as a strong predictor of mortality. For each 1-MET increase in exercise capacity, the adjusted hazard for death was 12% lower (hazard ratio􏰒0.88; confidence interval, 0.86 to 0.90). Compared with the least fit individuals (􏰎4 METs), the mortality risk was 38% lower for those who achieved 5.1 to 6.0 METs (hazard ratio􏰒0.62; confidence interval, 0.54 to 0.71) and progressively declined to 61% (hazard ratio􏰒0.39; confidence interval, 0.32 to 0.49) for those who achieved 􏰍9 METs, regardless of age. Unfit individuals who improved their fitness status with serial testing had a 35% lower mortality risk (hazard ratio􏰒0.65; confidence interval, 0.46 to 0.93) compared with those who remained unfit.

Conclusions—Exercise capacity is an independent predictor of all-cause mortality in older men. The relationship is inverse and graded, with most survival benefits achieved in those with an exercise capacity 􏰍5 METs. Survival improved significantly when unfit individuals became fit. (Circulation. 2010;122:790-797.)

i.e.- the men who could exercise the hardest and longest lived the longest.

more:

http://www.ncbi.nlm.nih.gov/pubmed/8426620?dopt=Abstract

RESTING HEART RATE AND MORTALITY

http://www.ncbi.nlm.nih.gov/pubmed/24290115http://www.ncbi.nlm.nih.gov/pubmed/23836802http://heart.bmj.com/content/99/12/882.long#ref-11

running over weight training!

http://www.ncbi.nlm.nih.gov/pubmed/24029163

Tyrannosaurus Rexing wrote:

say whattt??? wrote:

you are such a tool. your reply has nothing to do with my post. And the word SURELY you emphasized by capitalizing it was not used in my post you mental midget.

wow, just the sort of in-depth well researched opinion I'd expect from someone who posted the earlier unreferenced nonsense you posted earlier.

My post had everything to do with what you wrote. You strongly implied that it is very scientifically plausible and sound that running should lead to CVD. It's not a sound concept, and it isn't true. I listed several studies showing the positive impact of exercise (on ability to do well on exercise stress tests and resting heart rate) and its relation to all-cause mortality. Many other links have also been posted showing the positive effects of aerobic exercise on health and mortality.

The only mental midget here is you.

say whattt??? wrote:

Are you citing a blog as your source? Look, I am not saying that running is horrible for you. I am not saying this one study linked by the OP proves anything, but if you knew anything about physiology you have to accept the consequences of increased oxygen uptake on increased oxidation of free radicals and its consequences (CA and CVD) as well as the role of increased oxygen uptake on elevated metabolism, which isn't positive with its effects in regard to longevity.

Try researching things like the free radical theory on aging, or oxygen radicals on cellular damage, or free radicals and heart disease.

When we know things happen physiologically, we have better knowledge about what to expect. This specific knowledge removes barriers that research studies face, like in the OP, controlling for diet. We don't need to control for diet because we know that, regardless of diet, increased oxidative stress causes increased CVD, which is why these runners could have more plaque on their artery walls. Does this mean sooner death? Not necessarily...you get more collateral circulation with cardiovascular exercises which could offset this. But don't debunk the study because you think it doesn't control for things. At best, studies only show the need for additional studies and raise more questions. That doesn't mean you ignore them because you don't want to believe what they suggest.

mako wrote:

say whattt??? wrote:

Are you citing a blog as your source? Look, I am not saying that running is horrible for you. I am not saying this one study linked by the OP proves anything, but if you knew anything about physiology you have to accept the consequences of increased oxygen uptake on increased oxidation of free radicals and its consequences (CA and CVD) as well as the role of increased oxygen uptake on elevated metabolism, which isn't positive with its effects in regard to longevity.

Try researching things like the free radical theory on aging, or oxygen radicals on cellular damage, or free radicals and heart disease.

When we know things happen physiologically, we have better knowledge about what to expect. This specific knowledge removes barriers that research studies face, like in the OP, controlling for diet. We don't need to control for diet because we know that, regardless of diet, increased oxidative stress causes increased CVD, which is why these runners could have more plaque on their artery walls. Does this mean sooner death? Not necessarily...you get more collateral circulation with cardiovascular exercises which could offset this. But don't debunk the study because you think it doesn't control for things. At best, studies only show the need for additional studies and raise more questions. That doesn't mean you ignore them because you don't want to believe what they suggest.

The increased exposure to oxygen radicals during running is real, however you don't seem to understand the consequences of this. It stimulates the organism to produce its own anti-oxidants. So although you are exposed to free radicals increasingly during the short period of running, in the long term, you are more protected against them. That's also why they tell you not to take any anti-oxidants (in pills, fruit,..) immediately after a hard work-out because it interferes with the body's natural AO production.

So running is one of the best ways how to protect yourself against free radicals induced aging.

mako wrote:

say whattt??? wrote:

Are you citing a blog as your source? Look, I am not saying that running is horrible for you. I am not saying this one study linked by the OP proves anything, but if you knew anything about physiology you have to accept the consequences of increased oxygen uptake on increased oxidation of free radicals and its consequences (CA and CVD) as well as the role of increased oxygen uptake on elevated metabolism, which isn't positive with its effects in regard to longevity.

Try researching things like the free radical theory on aging, or oxygen radicals on cellular damage, or free radicals and heart disease.

When we know things happen physiologically, we have better knowledge about what to expect. This specific knowledge removes barriers that research studies face, like in the OP, controlling for diet. We don't need to control for diet because we know that, regardless of diet, increased oxidative stress causes increased CVD, which is why these runners could have more plaque on their artery walls. Does this mean sooner death? Not necessarily...you get more collateral circulation with cardiovascular exercises which could offset this. But don't debunk the study because you think it doesn't control for things. At best, studies only show the need for additional studies and raise more questions. That doesn't mean you ignore them because you don't want to believe what they suggest.

The increased exposure to oxygen radicals during running is real, however you don't seem to understand the consequences of this. It stimulates the organism to produce its own anti-oxidants. So although you are exposed to free radicals increasingly during the short period of running, in the long term, you are more protected against them. That's also why they tell you not to take any anti-oxidants (in pills, fruit,..) immediately after a hard work-out because it interferes with the body's natural AO production.

So running is one of the best ways how to protect yourself against free radicals induced aging.