Don't Run Forrest, Walk!

The Man, The Mountain… David Munn takes us through the dangers of running

How often do we hear about the benefits of cardiovascular exercise? How it’s so good for your heart, your lungs, and your belly? But amongst all things considered do we ever hear about the potential negative effects of cardio? And in particular, the risks associated with extreme endurance events such as marathons? Over the past few decades the popularity for marathons and other cardiovascular based sports has significantly increased. There are more than 10.5million runners in the UK, more than ever before and globally there has been an increase of 13% in marathon running.

Exercise is like a drug: too little and it’s effects have no impact, too much and it can destroy you. Now I admit this article may be a bit one sided*, but I agree that moderate forms of cardiovascular exercise do have some beneficial impacts upon health. However, at the same time, I do hate running. It is one sport I have never quite understood, and this is coming from a person who enjoys lifting heavy objects for no reason and putting them back down where they were before.

Firstly, I find running (except sprinting) very boring and arduous. And that’s just to watch! Let’s be honest, triathlons, marathons and track events only get interesting in the last lap. To actually participate I feel would be a living nightmare. Secondly I cannot for the life of me understand why people pay to enter such events. Why pay to run on the street? It’s like paying for tap water. Thirdly, and perhaps the whole point of this article, the stress and danger your body is put through participating in such an event – why do it?

For years many have argued over humanity’s ability to run long distances. In the paper, “Evolution of Marathon Running” authors Daniel Lieberman (Harvard University) and Dennis Bramble (University of Utah)(1) report that “for marathon-length distances, humans can outrun almost all other mammals and can sometimes outrun even horses, especially when it is hot.” Well, I guess that’s 1-0 Homo sapiens. But whilst we may very well be capable of achieving this, it negates whether this would actually be any good for our health. I’m sure even the horse would have enough sense to pack it in and live a more prosperous life than to die striving for gold-plated-silver. Even our glycogen stores only have around 18-20 miles worth in the tank: clearly less than what is required for a marathon.  Man was not built to run such long distances; we’re simply not designed for movement at a chronically sustained high intensity aerobic pace. Now, that’s not my excuse for being a couch potato, that’s fact, and history has shown this.

Let’s not forget the first person to ever run a marathon (Pheidippides, 490 B.C.) died upon completion. And even in the 21st century deaths are still occurring in marathon runners.  So why is this?

Firstly there’s always the risk of dehydration through sweat loss causing reduction in blood volume and glycogen stores. Studies show that a fluid loss of 2% of body mass is sufficient to cause a detectable decrease in performance, so get drinking! Then again, over hydration may in fact be what kills you. Over-consumption of hypotonic fluids (like water) leads to hyponatraemia. This can cause water to rush into brain cells causing hyponatraemic encephalopathy and ultimately brain stem compression and death if not treated. And before you start arguing that Lucozade will save you because it is “better than water”, think again! Hyponatremia can also develop from over-drinking sports drinks, despite the fact that most contain sodium salts.

Although frequent moderate cardiovascular exercise has been shown to protect against cardiovascular disease, a study presented at the Canadian Cardiovascular Congress in Montreal found that a large proportion of marathon runners have elevated cardiac troponin levels, a biomarker for cardiomyocyte damage, and that competitive marathon running can increase cardiac risk by seven fold. The troponin molecule should be found in very low levels in the blood, however, elevation is usually indicative of the cardiomyocyte necrosis i.e. a heart attack. As if that’s not enough, over years of training, left ventricular hypertrophy is common amongst endurance athletes. This thickening of the heart muscle again poses several potent risks such as coronary disease, stroke, and cardiac failure.  And then there are the long term effects of endurance running such as osteoarthritis After all, with 6 times your body weight traveling through your feet as you run, it’s a wonder your legs don’t shatter. Weaker immune system, osteoporosis, muscle cramps; the list of potential negative effects goes on…

So there we have it folks, long distance running: a great way of improving fitness or a path to an early grave? Either way what is clear is that even the elite “fittest” of us are just as prone to health problems as the couch potatoes. So I guess Darwin was wrong. It’s not survival of the fittest; but survival of the moderately fit.

Editor’s Note – Incredibly, agonisingly one-sided…Surgo takes no responsibility for anyone’s actions following Mr Munn’s “advice”

(1) Lieberman, Daniel E., and Dennis M. Bramble. 2007. The evolution of marathon running: Capabilities in humans. Sports Medicine 37(4-5): 288- 290.