Tuesday 5 July 2016

Let's Get Moving

There are lots of links between physical activity and health (see references at the end).

We've recently formed a partnership of official and voluntary bodies with the aim of encouraging the people they deal with  to incorporate physical activity into their everyday lives. Quite simply this means walking or cycling for some, or part of, the journeys that you'd normally make by car or bus.

To bring attention to this we've produced a Manifesto for Physical Activity for organisations to sign up to and, so that the something actually happens as a result, make some pledges about how they'd put this commitment into practice.


We acknowledge that physically inactive lifestyles are a major cause of ill health and premature death


We resolve to encourage the people we work with to incorporate regular physical activity into their everyday lives and to work with others to help make this possible.


We believe that one of the simplest ways for people to do this is to walk, or cycle, for some, or part of, the everyday journeys they currently make.


Now it's possible to produce a list of all the diseases where the risk can be dramatically reduced - Type 2 Diabetes, heart disease, various cancers and dementia - but this doesn't explain why such a simple thing as having a regular brisk walk can have such widespread effects. 

So, I began to look at the basic science and see if there was a simple underlying cause.. 


http://dx.doi.org/10.1113%2Fjphysiol.2009.179507
What happens when you stop being active

So, here's the simple story.

Our bodies have a whole host of complex feedback mechanisms that allow them to respond to changing circumstances. That's why your heart beats faster if you start walking quickly, why your pancreas releases insulin in response to a rise in blood glucose and why you start to shiver when you get too cold. The detailed mechanisms of nerves and signalling molecules are complicated but they work. 

These feedback mechanisms have evolved over our entire evolutionary history, since before homo sapiens existed, and expect us to be physically active.

Physiology, which I once studied in rather more detail than I can now remember, is the study of the normal functioning of the body and physiologists have looked at the experiments carried out on either sedentary humans, or caged animals that can't move about much, and discovered that it's often the inactivity that's causing the problems not whatever else is being done to them. E.g. mice that have been genetically engineered to be hungry put on weight and show many of the early symptoms of diabetes. Put a wheel in their cage so that they can run around and these effects disappear. (Booth and Laye J. Physiol 2009)

So, what's normal for the mice, and what's normal for us, is to be physically active and it isn't difficult to appreciate the evolutionary reasons why this should be the case. 

‘The selective advantages of increased activity capacity are not subtle but rather are central to survival and reproduction. An animal with greater stamina has an advantage that is readily comprehensible in selective terms. It can sustain greater levels of pursuit or flight in gathering food or avoiding becoming food. It will be superior in territorial defense or invasion. It will be more successful in courtship and mating’ (Bennett & Ruben, 1979)

That's it. Your body has evolved expecting you to be physically active. If you're not, then the regulatory systems that keep your heart and circulation working properly, keep your glucose control system working properly, maintain your bone density, reduce the risk of some of your cells multiplying uncontrollably (cancer), maintain good blood flow to the brain and help wounds heal etc. can't work properly.

Earlier posts

If it were a drug gives an overview of the health benefits of becoming active

The cost of sitting around in North Yorkshire looks at the likely health impact in the County of North Yorkshire if we got more people moving.

Finally, a picture that illustrates how we've been normalising sedentary behaviour.


Done Walking, started dying






5 comments:

  1. I think you need to start calling yourself "Dr. Andrew Sharp" (you are, after all, entitled to be so entitled). Possibly even with "B.Sc. (Oxon) Ph.D. (London)" tacked on (though that's tricky in conversation...). You'll find a little snobbery goes a long way in a good cause.

    Just out for a brisk walk! Lost 10 kilos in the last 6 months, and going for another 10! I'm disappearing!!

    Mike

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  2. Well Mike, you've now sort of done it for me. It all seems such a long time ago and it feels like almost everything I once knew has gone into hiding.

    For accuracy's sake it's

    BA (Physics and Philosophy) Oxford
    PhD (Physiology) Bristol
    Cert Ed (Further Education) Garnett College London
    PGDL (Law) College of Law York

    + I'm a certified Lead Auditor in Environmental Management

    Of all these, the most useless, and most readily forgotten, was the ridiculous venture into law. Never before have I done something that involved just learning stuff by rote, as opposed to sorting out the basic principles and then making up something plausible, and never before did I let my imagination run so far that I though law firms would be willing to take on an opinionated 40 something who clearly wouldn't work all the hours god sends..

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  3. Trying to see if that makes a word or could be sung... Nope.

    I'm doing the hand jive and tapping my toes as I sit here. Actually, the 5:2 diet has been a help, too. Oddly, no-one -- friend, foe, or medical practitioner -- has ever said to me, "Listen, porky, you could stand to lose a few stone..."

    Mike

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    Replies
    1. There's a wonderful piece of work by Tim Lang, formerly of the London Food Commision and now a Professor somewhere or other. The title was "Obesity, a policy cacophony" It basically looked at how all the vested interests had attempted to pose issues around weight in their own terms. So, the fast food manufacturers emphasised activity (i.e McDonalds sponsor sport), politicians wedded to the interests of the motor industry emphasised diet. His conclusion was that the health benefits of being active outweighed those of being a bit overweight and that the simple message should be "eat less and move more"

      I also suspect there's evidence that, unless patients are facing an acute crisis, telling them they could do with losing a bit of weight doesn't work. Your friends are probably just too polite.

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