Too much exercise

[Lucyhan]

http://www.thetimes.co.uk/edition/times ... -cdc9hsl86

Interesting read

[rualexander]

http://www.thetimes.co.uk/edition/times2/too-much-exercise-can-damage-your-heart-but-whats-too-much-cdc9hsl86

Interesting read

Only if you subscribe to the Times.

[Annoying Twit]

The newspaper article is useless as it doesn't give a reference to the original research, and doesn't say how much exercise is too much or why.

Here's a research article which may be the one being discussed.

http://www.ncbi.nlm.nih.gov/pubmed/22953596

Abstract
A daily routine of physical activity is highly beneficial in the prevention and treatment of many prevalent chronic diseases, especially of the cardiovascular (CV) system. However, chronic, excessive sustained endurance exercise may cause adverse structural remodeling of the heart and large arteries. An evolving
body of data indicates that chronically training for and participating in extreme endurance competitions such as marathons, ultra-marathons, Iron-man distance triathlons, very long distance bicycle racing, etc., can cause transient acute volume overload of
the atria and right ventricle, with transient reductions
in right ventricular ejection fraction and elevations of cardiac biomarkers, all of which generally return to normal within seven to ten days. In veteran extreme endurance athletes, this recurrent myocardial injury and repair may eventually
result in patchy myocardial fibrosis, particularly in the atria, interventricular septum and right ventricle, potentially creating a substrate for atrial and ventricular arrhythmias. Furthermore, chronic, excessive, sustained, high- intensity endurance exercise may be associated with diastolic dysfunction, large-artery
wall stiffening and coronary artery calcification. Not all veteran extreme endurance athletes develop pathological remodeling, and indeed lifelong exercisers generally have low mortality rates and excellent functional capacity. The aim
of this review is to discuss the emerging understanding of
the cardiac pathophysiology of extreme endurance exercise, and make suggestions about healthier fitness patterns for promoting optimal CV health and longevity.

(my emphasis.)

[axel_knutt]

The reason there's no reference cited is because it's "New, as yet unpublished, research". He doesn't say whet he mans by heart "disease", but if it's arrhythmia, that's nothing very new. On the other hand, if they've been able to put quantitative axes on the U-shaped dose-response curve, that would be new AFAIK.

[Annoying Twit]

The reason there's no reference cited is because it's "New, as yet unpublished, research". He doesn't say whet he mans by heart "disease", but if it's arrhythmia, that's nothing very new. On the other hand, if they've been able to put quantitative axes on the U-shaped dose-response curve, that would be new AFAIK.

My opinion of the accuracy of science articles in the mainstream press means that even if they say it's unpublished research, that doesn't mean that it is. Maybe we'll find out.

[fishfright]

I always regard unpublished research with the same gravitas as 'a bloke down the pub reckons'.
Publishing in a reputable journal is only the start of proper critical appraisal. Can you tell i'm not a Fail journo ? lol

[whoof]

If it's not been published (in a scientific journal) then it's not been peer reviewed. If it's been published in the Times then chances are it won't be published by a scientific journal because it's not new research as it's been published elsewhere (self plagiarism), i.e. the Times. Whilst getting media coverage is nice, publishing in peer reviewed scientific journals is what scientific researchers do, it's how they demonstrate that they are getting results and has impact on everything from obtaining future funding to moving up the career ladder.

[axel_knutt]

If it's not been published it's either because the peer reviewers have rejected it, or because the work's not finished yet.

[Annoying Twit]

If it's not been published it's either because the peer reviewers have rejected it, or because the work's not finished yet.

I do want to see what the work is when it's published. It might not have been rejected, and it could be finished. (Though either of the above COULD apply.) The main reason I want to reserve judgement until the work is published is in case the newspaper article has misinterpreted the findings. Which happens very often.

[axel_knutt]

There's quite a lot of other research accumulating finding a link between an increased risk of AF and a chronic history of endurance exercise, it's not a novel finding. If you want to see the research that's already been published let me know and I'll give you a copy my reading list. Porter is a doctor, not a journalist, he presents Inside Health on Radio 4 too, which covered this subject in February last year.

[meic]

It seems credible that too much exercise can do harm to your heart as well as your joints.

I wonder what proportion of the population will get themselves into this position and how the outcome compares to the much larger (in many ways) group at the other end of the spectrum.
It really isnt something that I will be worrying about, even as an infrequent Audax rider.

[Annoying Twit]

There's quite a lot of other research accumulating finding a link between an increased risk of AF and a chronic history of endurance exercise, it's not a novel finding. If you want to see the research that's already been published let me know and I'll give you a copy my reading list. Porter is a doctor, not a journalist, he presents Inside Health on Radio 4 too, which covered this subject in February last year.

What I'd like to know is the balance between harm due to excessive endurance and the benefit. People here have already mentioned benefit curves, but we need to know where the tradeoff is. Sometimes research such as this only considers one aspect of the benefit equation for ... something. It could be that risk of heart attack goes up slightly if exercise is excessive, but perhaps the risk of something else goes down and the overall risk/benefit is complicated.

If you know of papers that answer these questions, I'd very much to read them.

[david7591]

Listen to your body. I know when I've done to much. I feel tired. My muscles may ache. If your aim is improved performance, recovery is just as important as the actual training.

[axel_knutt]

What I'd like to know is the balance between harm due to excessive endurance and the benefit. People here have already mentioned benefit curves, but we need to know where the tradeoff is. Sometimes research such as this only considers one aspect of the benefit equation for ... something. It could be that risk of heart attack goes up slightly if exercise is excessive, but perhaps the risk of something else goes down and the overall risk/benefit is complicated.

If you know of papers that answer these questions, I'd very much to read them.

Studies by Gebel et al., and Arem et al. both found a law of diminishing returns when it comes to overall mortality and exercise dose. The biggest benefit comes from the moderate amounts of exercise, with relatively little further improvement from increases above the levels generally recommended for good health. I've plotted their data below, along with the recommended levels of exercise in green and my exercise levels in red:

Schnohr et al. found that "up to 2.5 hours of jogging a week at a slow or average pace and a frequency of ≤3 times per week seems to be associated with the lowest mortality."

and that "that the relative intensity, and not the duration of cycling, is of more importance in relation to all-cause and coronary heart disease mortality."

and "the relative intensity and not the duration of walking is of most importance in relation to all-cause mortality"


Gebel, Ding, Chey, Stamatakis, Brown, Bauman:
Effect of Moderate to Vigorous Physical Activity on All-Cause Mortality in Middle-aged and Older Australians.

Arem, Moore, Patel, Hartge, Berrington de Gonzalez, Visvanathan, Campbell, Freedman, Weiderpass, Adami, Linet, Lee, Matthews:
Leisure Time Physical Activity and Mortality: A Detailed Pooled Analysis of the Dose-Response Relationship.

Schnohr, Marott, Lange, Jensen:
Longevity in Male and Female Joggers: The Copenhagen City Heart Study

Schnohr, Marott, Jensen, Jensen:
Intensity versus duration of cycling, impact on all-cause and coronary heart disease mortality: the Copenhagen City Heart Study

Schnohr Scharling Jensen:
Intensity versus duration of walking, impact on mortality: the Copenhagen City Heart Study

[Annoying Twit]

Thanks. The paper by Schnohr et al is summarised here: http://spo.escardio.org/eslides/view.as ... 48&fp=5178

That really is a striking result.

I'm about to cycle home now. Quickly.

The u-shaped results are presented here: http://aje.oxfordjournals.org/content/e ... ws301.full (If not in as nice a graph as I'd like).