Uh, OK, you don't know.
Uh, OK, you don't know.
you don't really understand much about science.
ramses wrote:
You tell me since, based on your assertions, have already read the full study. lol
Face it. Running is bad for you...running marathons is VERY bad for you. This has been shown again and again.
Here's my study:
100% of those individuals that develop heart disease have eaten carrots. Therefore, the only logical explanation is that carrots cause heart disease.
I would say the #1 link to heart disease is genetic...hands down. Did the study look into genetic factors of each of the groups or did it overlook that minor detail?
dumb wrote:
Study Reader wrote:http://www.runnersworld.com/health/too-much-running-myth-rises-again?page=singleCox regression is not relevant to the study linked in the OP.
They did essentially the same thing in this study. They picked only control subjects with a similar resting heart rate, blood pressure, etc.
I've looked into this subject a lot, and I can only find one study that looks at weekly mileage vs mortality rate:
http://indorgs.virginia.edu/MuscleClub/OKeefe_JH_article1%2B2.pdf
All of the recommendations to keep mileage below 20 miles per week comes from Figure 4 on Page 3 of that document. It also shows that running more than 25 miles per week is still linked to a longer lifespan than a sedentary person, but let's ignore that fact. After all, there's no news like bad news!
As for arterial plaque, Lots of heart scans in several studies show a strong correlation between marathoning a lot and having high plaque levels. But running also does a lot of good things, like lower blood pressure, strengthen the heart, improve cholesterol, etc. In other words, running does good things and bad things for your body. Not really surprising when you think about it that way.
So when does the bad outweigh the good and we start having shortened lifespans because of it? According to one study, 20 mpw or more. But there's only been one study like this. The jury is still out.
One that has been peer reviewed and published in a scholarly journal. But I'm sure you are a better judge of the methodology and results. LMAO
Be serious- one study of 50 people is not conclusive in any way.
if running is so bad for your health then why do so many runners live long, healthier lives?
"They've" trying to discredit running since before Jim Fix died.
So many people don't understand science.
Science BAAAAAD! Me no want to hear it.
So many people don't understand science.
Science BAAAAAD! Me no want to hear it.
Who are "they?" Your tin foil hat is crooked.
runn wrote:
One that has been peer reviewed and published in a scholarly journal. But I'm sure you are a better judge of the methodology and results. LMAO
Be serious- one study of 50 people is not conclusive in any way.
if running is so bad for your health then why do so many runners live long, healthier lives?
"They've" trying to discredit running since before Jim Fix died.
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.
You can't outrun a bad diet.
Runners fare favorable compared to sedentary people because those are often fat and live a rather unhealthy lifestyle on top of that.
Compare:
Person A - runs 70mpw, eats mostly bread and junk food, BMI 20
Person B - never runs, eats a healthy diet low in simple/processed carbs, BMI 20
Who is healthier?
Easy: Person B.
A good article on why endurance training is unhealthy:
http://www.marksdailyapple.com/the-evidence-continues-to-mount-against-chronic-cardio/
But I read that if the fire was hot enough it could burn anything!
Lol!
Might be useful if they were identical twins.
Here's a great article in the NY Times on how limited the usefulness of epidemiological studies like this one are:
http://www.nytimes.com/2007/09/16/magazine/16epidemiology-t.html?pagewanted=1&_r=1
A summary:
This science evolved over the last 250 years to make sense of epidemics — hence the name — and infectious diseases. Since the 1950s, it has been used to identify, or at least to try to identify, the causes of the common chronic diseases that befall us, particularly heart disease and cancer. In the process, the perception of what epidemiologic research can legitimately accomplish — by the public, the press and perhaps by many epidemiologists themselves — may have run far ahead of the reality.
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.
Precious Roy wrote:
say whattt??? wrote:why I it so damn hard for runners to admit that too much running can have negative physiological consequences?
Because it probably doesn't.
The recent Boston Marathon study normalized for lifestyle and found that there was no correlation between the amount of running and increased heart disease risk.
http://well.blogs.nytimes.com/2014/03/12/what-running-can-do-for-the-heart/?_php=true&_type=blogs&_r=0When you take a complete look at a runner (mileage AND diet), the picture is quite clear. Running does not negate a bad diet. But there is no evidence that running is harmful when you have a good diet.
[quote]say whattt??? wrote:
why I it so damn hard for runners to admit that too much running can have negative physiological consequences?
[quote]
Too much running can have negative consequences. There. That wasn't hard to admit at all. What's hard is determining exactly how much running is "too much" because not everyone is alike.
These studies always seem to end up tossing out a number of miles per week that's "safe" and letting it stand. Twenty five miles a week seems to be the current "safe" number. But we all know that twenty five miles at a 5:30-6:00 pace is not the same as if it's done at an 8:00-10:00 pace. Twenty five miles a week is not equally stressful for someone like me, who once ran 100-150 mile weeks as it would be for a fifty year old guy who's been sedentary for the past 30 years and may have smoked or drank heavily in that time. It would be easier to take these sorts of studies seriously if they did not throw out all these one size fits all recommendations.
Some years back, the late Ralph Paffenbarger, who was a passably decent marathoner/ultra-marathoner who was on the faculty at Harvard Med did a very well reviewed long term longitudinal study with some other Harvard guy whose name I can't recall, on the longevity of distance runners compared to sedentary people. They only looked at life span, not at anything internal, (i.e., there was no information about plaque, cholestrol, inflammation, blood pressure, etc.) and found that every minute you spend running adds a minute to your life span. I've never seen this study referenced or refuted in any of these "running is bad for you" articles.
I think that's very significant because longevity is not determined by a single factor. We'll never know how "healthy" any of the people in Paffenbarger's study were or were not. Their arteries could have been clean as whistles or clogged as an airport TSA line on the day before Thanksgiving. But they lived longer than non-runners.
[quote]say whattt??? wrote:
why I it so damn hard for runners to admit that too much running can have negative physiological consequences?
[quote]
Too much running can have negative consequences. There. That wasn't hard to admit at all. What's hard is determining exactly how much running is "too much" because not everyone is alike.
These studies always seem to end up tossing out a number of miles per week that's "safe" and letting it stand. Twenty five miles a week seems to be the current "safe" number. But we all know that twenty five miles at a 5:30-6:00 pace is not the same as if it's done at an 8:00-10:00 pace. Twenty five miles a week is not equally stressful for someone like me, who once ran 100-150 mile weeks as it would be for a fifty year old guy who's been sedentary for the past 30 years and may have smoked or drank heavily in that time. It would be easier to take these sorts of studies seriously if they did not throw out all these one size fits all recommendations.
Some years back, the late Ralph Paffenbarger, who was a passably decent marathoner/ultra-marathoner who was on the faculty at Harvard Med did a very well reviewed long term longitudinal study with some other Harvard guy whose name I can't recall, on the longevity of distance runners compared to sedentary people. They only looked at life span, not at anything internal, (i.e., there was no information about plaque, cholestrol, inflammation, blood pressure, etc.) and found that every minute you spend running adds a minute to your life span. I've never seen this study referenced or refuted in any of these "running is bad for you" articles.
I think that's very significant because longevity is not determined by a single factor. We'll never know how "healthy" any of the people in Paffenbarger's study were or were not. Their arteries could have been clean as whistles or clogged as an airport TSA line on the day before Thanksgiving. But they lived longer than non-runners.
Actually, Paffenberger's study concluded that every hour you spend exercising adds tow to three hours to your life span.
Tell this to Harry Groves. Ran high mileage for years and he is currently getting even with all the no good sons of bitches he is out living.