Is Running Bad For Your Heart?

Now here’s a funny thing: I was about to write a few linked posts about the importance of exercise for health and the difficulties of changing habits and persuading  adults to make even a minimal effort, when I came across an article warning that exercise might have dangers. (Not that there's anything in it to change my plans as only good things can happen if someone moves from inert to 150 minutes a week). No the dangers are for those who are are worried about their health but for those who become intoxicated by the challenges, the idea of pushing back physical limits, and addicted to the feeling of being both physically empty and extremely satisfied.  Doing too much, or more specifically taking part in endurance events like marathons, triathlons, or ultramarathons might not actually be too healthy. There may be some unwanted adaptations to the heart and it is possible there is a dose effect so that just as too little exercise is bad for a body running too much might not be so good!

The origin of the concern was a paper has been published in Mayo Clinic Proceedings entitled ‘Potential adverse cardiovascular effects from excessive endurance exercise’ and many of you might not want to read any further than the title. Feel free to close your eyes, put your fingers in your ears, say “I am not listening!’ or ‘this cannot possibly be right because I don’t want to believe it’. If you write for a newspaper you can do this at slightly greater length. That’s OK as long as you are clear in your mind why you run and know that if you run for more than about 30 minutes a day you do so for reasons other than health.  However although we might want to continue doing what we do we should not treat unwelcome sounding research like and leave it unopened like an unwanted bank statement. We must face it dispassionately to see what the researchers actually say and be prepared to put aside our preconceptions. Before doing so though we can be strengthened by the thought that what is actually proved in any scientific papers is usually very specific within precisely defined limits which often do not bear the weight of the more generalised (and lurid) headlines.

So what to make of the Mayo paper?  Well from my lofty position of a non-expert it looks like a good survey of what is known about the effect of extreme exertion on the heart. It shows evidence that the hearts of highly trained athletes can enlarge and thicken in a way that would be seen as worrying for a normal person and there can also be scarring and other damage. However we don’t know enough about what that means for overall health and longevity, as the authors recognise in the abstract: 

However, this concept is still hypothetical and there is some inconsistency in the reported findings. Furthermore, lifelong vigorous exercisers generally have low mortality rates and excellent functional capacity.

Nevertheless there is enough in this paper to get one thinking. But it must be emphasised that the authors are not warning about exercise of itself, instead they are raising the question as to whether there can be too much of a good thing. They explicitly offer no excuse for the couch potato to remain inert as their opening sentences make clear:

Regular exercise is one of the cornerstones of therapeutic lifestyle changes for producing optimal cardiovascular (CV) and overall health. Physical exercise, though not a drug, possesses many traits of a powerful pharmacological agent. A routine of daily physical activity (PA) stimulates a number of beneficial physiologic changes in the body and can be highly effective for prevention and treatment of many of our most prevalent and pernicious chronic diseases, including coronary heart disease (CHD), hypertension, heart failure, obesity, depression, and diabetes mellitus.¹ People who exercise regularly have markedly lower rates of disability and a mean life expectancy that is 7 years longer than that of their physically inactive contemporaries.

The point needs to be emphasised because there is no way you want a simplified message that running is bad for your health to seep into the public consciousness. It shouldn’t from this paper, which is a restrained academic review that does not editorialise. However that is done by the authors in the BMJ journal Heart, where they are clearer in describing the effect of exercise as a U curve where too much high intensity work loses some of the gains of a more moderate regime. (It can be found here but unless you have a subscription or access from a library it is not worth the £24 they want to charge. Instead watch the TED talk that covers the same ground). 

The article has caused more controversy because it inspired the article in the Wall Street Journal I previously mentioned. As is common for newspapers the headline and opening paragraphs were overly alarming, even if there was more balance further down the piece (as is also common in newspapers). This has been a push back with some people to contest the conclusions (e.g. here and here) and a little flurry of concern.

My take (for what it’s worth - and that is very little because it is just the intuitive response of someone who runs about a bit) is that I am very ready to believe that there is a sweet spot for exercise to offer maximum health benefits, which might not accord with the amount of work needed to fulfil other ambitions. It is very likely that more might not mean better especially for those of us over 50. But I am not sure if I have to worry too much. I may be old but the amount of running I do faster than 8 min miles is vanishingly small. I, like most people, am probably well within the boundaries of exercise being a good thing. However the problem is we cannot precisely define where those boundaries are. Take for example easy exercise: apparently we can walk as much as we like without hitting  a point of diminishing returns but does that also apply to slow, low intensity running?  If so the majority people who run marathons have no worries because, from the middle to the back of the pack, the long slow running dominates training (and the race). For most people the debate about a U shaped exercise curve is irrelevant because we don’t run hard or fast enough to reach the bottom of the U. The people at risk are the seriously competitive and they are the very people whose motivation has nothing to do with wellbeing or health. But the amount of that risk, if at all, is not yet known. 

It is all neatly summed up in an article in Outside about the original Mayo review: “high-intensity, high-volume exercise is really, at this point, a black box in terms it what it does for you over the long haul.”

uneathon 2012 Day 11 - More on exercise and depression

Juneathon 2012 Day 11 - More on exercise and depression

Walk - 1.6 miles,  Time - 30min, Weather - raining stair rods, terrible day, so out for as short a time as possible

A day spent watching the rain come down and listening to water pouring out of drains. Juneathon exercise was negligible - the barest minimum and all dressed up in waterproofs.


So to blogging and it is with a heavy heart I have to return to the subject of exercise and depression because the optimism in my summary of reaction to the research was misplaced. I had thought the follow-up to the original news reports had left us better informed and we had got beyond the exaggerated headlines. But I was wrong.

Sam Murphy is a highly respected journalist who writes on fitness and health but particularly specialises in running. She has written a number of books and writes regularly for the Guardian and in all her works she likes to quote research and researchers. As well as this she puts her knowledge into practice by running to a good standard and by coaching. In other words she is an authority  So I was rather sad to read this Tweet:

Sam Murphy @SamMurphyRuns 
Excellent response from Simon Hattenstone to unhelpful research saying exercise 'no good' for depression gu.com/p/385jc/tw via @guardian

The first, and in many ways the least important, reason is that she misunderstands the findings. It didn’t show exercise was 'no good' for depression, instead it said a particular intervention had no significant long term benefit - something very different. It meant she hadn’t followed-up to look in any detail at what the research was about instead she just reacted to the headlines. That might be slightly disappointing for journalist with her expertise but it is not an unforgivable sin; after all who amongst us, at sometime or other, has not offered an instant opinion based on partial information. The trick then is to acknowledge the mistake and find out more

However the second reason for my reaction to the Tweet makes me suspect this will not happen. The use of the phrase “unhelpful research” suggests an already closed mind that only wants to accept research that confirms pre-existing beliefs. I am sure if the findings had shown a positive effect for the exercise programme she would not have called it unhelpful. If so her problem is with the results not the research (especially as this particular piece of research, by examining the efficacy of a particular form of treatment, was designed to be very helpful indeed).  Having a problem with the results is not grown-up, it’s a bit like throwing a hissy fit if your team loses. It is sometimes you have to deal with. You have to look at the scope and limitations of the research and whether the conclusions are fully supported. Are there alternative explanations? What more needs to be known? 

Like Sam Murphy I am strongly convinced exercise is thoroughly beneficial but when I come across some evidence that seems to challenge this belief I don't want to say it is unhelpful. I want to say "Hmm I wonder how that relates to everything else we know?". To dogmatically assert exercise is good is not an adequate response

Juneathon 2011 Day 18: Research findings in the press

2011 Streak Day 169/365: Walk - 3.1 miles, Time- 55min, Weather - showers (some fierce)

Obedience Training

One of the pleasures of Saturdays is to spend time in a coffee shop, reading the paper.  I positively enjoy the sensory experience of opening and turning the pages of a traditional paper and the way it feels luxuriant to be at your ease and give each story its proper attention.

So today’s exercise was a 1.5 mile walk out , a long gap and then 1.5 miles back. (On my way I saw a man in the park training his dog and took a photo)

One of the ‘must reads’ in Saturday’s Guardian is Ben Goldacre’s Bad Science column. Today his subject was his research into the quality of health advice in newspapers. Although it is unsurprising that he found it to be shaky (of the 111 claims made in a week the majority were supported by evidence that was categorised as ‘insufficient’) there are serious consequences. People make decisions based on what they read in the papers because it is the most important gateway to advice.

The problem is the jackdaw approach to research papers: those with quirky, amusing, counterintuitive, or controversial findings tend to be picked-up regardless of how well founded they are. They are then given the intro of “science has found...” as if the voice of authority has spoken. This can be very confusing.

Specialist publications should be better but I don’t think they are. If you look at Runners World or Men’s Health, or the like, there are often suggestion that a particular food has specific properties based on some research, or findings about the effects of different ways of exercising. Frequently they are short paragraphs and completely avoid anything as pesky as an evaluation of the evidence base.

My assumption that specialist publications should be better informed because as they have a narrower focus is probably unfair. They are written by journalists with space to fill and research findings can be an easy way to produce copy. If a subject becomes a hot issue it will then be looked at in more detail with a more balanced approach but otherwise there are a lot of throw-away paragraphs.

This approach might be OK for running (just), whilst still being dangerous for general health. Health consequences are long-term and diffuse. It is difficult to know the full effects of any change of behaviour and there are just too many confounding factors. Running in contrast is very specific - you want to go longer or faster (or ideally both) and you can directly measure your progress. It is thus possible to try something for a couple of weeks and then either abandon or continue according to results.

Research can therefore offered in the spirit of “this might be worth a go” and I am happy with that. We should never forget that we are an experiment of one.

However when advice becomes definitive, or strays from training into nutrition and general health, we really owe to ourselves to check the evidence base to see that it is solid.

Looking at nature

Most of the pictures on this blog are of canals and trees, in other words natural surroundings (even if canals are man made). It is the way I think of my runs - chugging along looking at trees and water, passing people who are outside to enjoy themselves. I think of my standard run as 1 hour along the canal but in reality less than half the time is spent on the towpath as I have to get there and it is 16 minutes away. But the streets on the way tend to pass in a blur and I think of them as a preamble (word chosen carefully to reflect my running speed) that has to be got through. It is a bit odd as it is all running and everything should be of equal value.

Now I find there might be a good reason for this: nature is better for your state of mind.

"Attention restoration theory" is the current rebranding of the idea that a walk in the woods can help refocus your thoughts. Think of the Romantics tramping the Lake District or Thoreau at Walden and know the idea has been around for a long time but to be contemporary it has to have a three letter acronym so it is now ART. ART hypothesises that nature engages our attention and our sense of beauty in a way that places no load on the prefrontal cortex. In other words the mind can freewheel and give our directed-attention faculties a chance to recuperate. In contrast a walk in an urban environment is full of stimuli that require immediate attention and is therefore not so restful.

Last year this was tested in an experiment at the University of Michigan. A group of people were given some backwards number tasks that required a deal of concentration. After the first session they took an hour walk either in an arboretum or along the streets of Ann Arbor, after which they took more tests. Whilst everyone's scores improved those of the nature walkers improved significantly more than those who had gone downtown. A second experiment cut the walking, instead the participants looked at pictures of either nature or urban scenes in their break. Again those who had looked at the nature scenes improved more.

So there you have it. If you want your run to have the maximum restorative effect you should search out routes containing natural beauty. Any run is obviously good but some places just make you feel that little bit better.

Scientifically proved!

Official Advice on Exercise Pt 2

Official advice on the amount of exercise needed is quite simple:

■ Children and young people should achieve a total of at least 60 minutes of at least moderate intensity physical activity each day. At least twice a week this should include activities to improve bone health (activities that produce high physical stresses on the bones), muscle strength and flexibility.
■ For general health benefit, adults should achieve a total of at least 30 minutes a day of at least moderate intensity physical activity on 5 or more days of the week.
■ The recommended levels of activity can be achieved either by doing all the daily activity in one session, or through several shorter bouts of activity of 10 minutes or more. The activity can be lifestyle activity or structured exercise or sport, or a combination of these.
■ It is likely that for many people, 45-60 minutes of moderate intensity physical activity a day is necessary to prevent obesity. For bone health, activities that produce high physical stresses on the bones are necessary.
■ The recommendations for adults are also appropriate for older adults. Older people should take particular care to keep moving and retain their mobility through daily activity. Additionally, specific activities that promote improved strength, co-ordination and balance are particularly beneficial for older people.

That’s all there is.

When I first read them I thought they were very soft. There is no mention of vigorous, nothing about raising the pulse rate or breathing heavily and nothing about being able to gradually do more with practice. As for breaking it up into 10 minutes units I thought it was the slippery slope to counting any slight movement as exercise.

But I was probably being a bit snooty because I run and know the feeling of wellbeing that sweeps through you after a good session. I therefore know in my bones that exercise is good for you. So my viewpoint is distorted especially as I have little understanding of the general level of inactivity in the population as a whole or how hard it is to start from a low base.

Reading the 2004 report by the Chief Medical Officer changed my mind (it can be downloaded here) as it shows the evidence base for the recommendations, which can be summarised by this quote:

The World Health Organization has reported that physical inactivity is one of the 10 leading causes of death in developed countries, producing 1.9 million deaths worldwide per year.21 It estimates that physical inactivity is responsible for the following proportions of ‘disability-adjusted life years’ in developed countries:

■ 23% of cardiovascular disease for men and 22% for women
■ 16% of colon cancer for men and 17% for women
■ 15% of type 2 diabetes
■ 12% of stroke for men and 13% for women
■ 11% of breast cancer. Becoming more active can bring substantial benefit.

There is a clear dose-response relationship between physical activity and all-cause mortality, and between physical activity and diseases such as coronary heart disease and type 2 diabetes: greater benefits occur with greater activity participation (see Figure 1). From a public health perspective, helping people to move from an inactive level to low to moderately active levels will produce the greatest reduction in risk. A physical activity energy expenditure of 500-1,000kcals per week (about 6-12 miles of walking for an average-weight individual, compatible with the current physical activity recommendations for adults) reduces the risk of premature death by 20-30%. These considerable health benefits hold for both women and men and are evident even up to the age of 80 years.

This is clear. If more people adopted this regime of moderate exercise there would be dramatic change. However in the back of my mind is the quote from Jerry Morris saying that vigorous activity was necessary and his survey of civil servant showed gardening was not enough. I presume later surveys have different results but is vigorous exercise really unnecessary?

It seems that there is might be some debate. In 2007 the American Heart Association modified its advice by incorporating vigorous exercise and resistance training. The base recommendation was still 30 minutes of moderate activity 5 times a week, but 3 sessions of vigorous exercise could be substituted, if preferred, or moderate and vigorous sessions could be mixed. The Guardian report of this change was exaggerated and had the headline “The era of gentle exercise is over: it’s official you’ve got to work up a sweat”, which is a complete misrepresentation (the NHS Behind the Headlines response is here). Although the American report was merely an enhancement of the existing recommendations, it did acknowledge that there were still some people who believed that only vigorous exercise had a health effect and that recent evidence gives some indication that vigorous exercise is more beneficial for cardiac disease.

However in terms of a public health message the last thing you want is debate. It is important to stand firm with advice and only change it when counter evidence is very clear. Any sign of confusion is an excuse for people to do nothing. You need only look at diet, where there is a perception of scientists always changing their minds (even if this is not the case) to see how that works.

Additionally getting people to move from nothing to something is very difficult and you do not want to make the task seem daunting. (Again diet is the example ‘5 a day’ for fruit and vegetables was chosen as a target that would not be too off-putting; it is not necessarily the optimum).

So I can now see why the current advice is good. It has a the maximum chance of making an impact but it needs to seep into the general consciousness in the same way as '5 a day'. If we walk on average only half a mile a day and 38% of adults have less than 30 minutes of moderate activity a week. There is a long, long way to go.

More Jerry Morris

I have been thinking more about the article about Jerry Morris I linked-to recently and realise that I need to explain why I found it both interesting and uplifting.

The main reason is a straightforward admiration for anybody who has spent his life trying to make things better for others. Such people, who try to solve problems practically, based on knowledge and understanding, are the backbone of the country (compared to most of the people in the media who seem to float on clouds of opinion). Jerry Morris was a high level example and, from the evidence of the article, it looks as if he led a virtuous life.

Times Past

Another reason is probably nostalgia. When I read it I could almost imagine a black and white film of the forties with the central character calmly displaying determination in the face of adversity, moral strength, and practical intelligence (he would probably have to be played by John Laurie because I think it was the law at the time that all Scotsmen had to be played by John Laurie). But deeper than an internal cinema is the attraction of looking back at what has changed and what is still the same.

He worked when we were changing from a physically demanding life to the more domesticated, sedentary world we now inhabit. To be able to compare bus drivers to bus conductors was a wonderful opportunity because class, background, lifestyle, diet of both was very similar and it was possible to isolate the differences caused by exercise. This is no longer the case: there are very few conductors; there are far more differences between those who take exercise and those who don't and there are far more confounding factors.

I also found his regret at the passing of the can-do attitude of the 40s to be poignant. i am sure that it is not that we are any less practical or enterprising now but rather we have lost faith in the idea that national plans and initiatives can make things better. Our default position is cynicism and it is a shame that it is so. The post war period, up until the mid 70s, was probably the high point of optimistic thinking, ie a belief that life could be made better, planning could improve the lot of everybody and the application of science would be beneficial. It is not easy to recapture that mood but I still think there is a lot to recommend in the idea of rounding-up all the experts on a subject, sending them away to the Hebrides and not letting them back until they come up with a workable plan.

Applying the Lessons

Although he made is discovery a lifetime ago, there is now a general understanding of the importance of exercise, I am not sure the full message has been accepted. He is very clear that there needs to be vigorous exercise (gardening by itself is not enough) but a lot of the health advice offered today tones that down. We pussyfoot.

I looked at the exercise recommendations on the NHS Choices. Although it contains some sensible advice, nowhere does it mention the need to raise the pulse rate. Vigorous? The word is shunned as we cannot make even the tiniest suggestion of effort in case we scare people off. I understand the motive, and we certainly don’t want to make things seem overly forbidding, but our bodies were evolved for exercise; there is pleasure in breathing heavily. More to the point vigorous exercise is necessary and we are diluting what we know to be true in an effort to make it more palatable. That does nobody any good.

“Exercise normalises the working of the body”. I like that quote. I think it should be at the head of all the health advice.

The Necessity of Exercise

This quote says it all:

“For the first time in history,” says Morris, “the mass of the population has deliberately got to take exercise. It’s a new phenomenon, which is not appreciated.” For decades he has tried to persuade governments to make exercise easier. He was involved in the pioneering English National Fitness Survey of 1990, which found that half of women aged 55 to 64 could not comfortably walk a mile. These people were in effect disabled. The government ignored the report. Since then, British exercise levels haven’t changed much. His voice becomes high-pitched with outrage: “Just imagine, what historians in the future are going to say about the way we’ve allowed this epidemic of childhood obesity. ‘Disgrace’ is a sort of mild word.”

Sad Songs

My daughter wanted to listen to some music on her run and asked to borrow my Ipod. Scanning through the contents she soon came to the conclusion that I had nothing suitable for running. She pointed out, quite accurately, almost all my music is miserable, I listen to very little that is bouncy and virtually nothing that has the driving beat found on most tracks recommended for running

I thought about this when reading I run because I like food's list of favourite running songs and realised I do not have a single song I would recommend as good for running. At the same time, when running, I enjoy almost everything on my Ipod.

It is a real pleasure to put it on shuffle so that you never know what will be next. Songs can sometimes seem fresher when heard against something unrelated. Seeing how long it takes to recognise a new track can be diverting, as is the game of trying to make associations between each piece of music. It does not matter if the music is fast or slow as it's function is to take attention away from the state of your legs and this is how I use it. I take an Ipod on long runs to make them just a little bit easier.

The effectiveness of music in increasing endurance and lessening the perception of pain has recently been tested (an account can be found ,here). It involved 80 people plunging their hand into icy water for as long as they could up to a limit of five minutes (for some reasons ethics committees seem to baulk at the risk of inflicting real physical damage). They did this first looking at a blank wall, then a piece of art, and then some music of their choice. The visual stimulation of art did not affect the length of time people kept their hand in the water (although they said it helped them distract themselves from the pain). However music had a significant effect and pain could be endured longer and felt less.

This is directly applicable to running. Music can help, all you have to do is choose things you like, whatever that may be - even miserable stuff.