Science Show

Nick Wareham is investigating the determinants of physical activity and measuring the influence of the environment and the way we live on the amount of physical activity we engage in.

Transcript

Robyn Williams: Obesity has been another recurring niggle during 2006, but there are two parts to being big. One is your own individual biology and the other is what kind of society you live in. Now Dr Nick Wareham in Cambridge is trying to put the two together to see what comes out.

Nick Wareham: Sure, we know that physical inactivity is part of the causation of obesity and partly attributable to why we have a rising prevalence in this country. The question we're trying to address in this study is what are the determinants of physical activity? And it's deliberately broad-brushed because previous studies have tended to focus on individual determinants of activity and they've tended to ignore the wider determinants related to the physical environment, and we need to try and have both in one study because our solutions may lie in both areas.

Robyn Williams: So how are you going to get both into one study, practically speaking?

Nick Wareham: You can collect the environmental data by overlaying that. Provided you know where someone lives and where they work or where they go to school, the other information about the access to green space, the street layouts et cetera, that's overlayed information which is collective.

Robyn Williams: One of the things that you do notice these days is how amazingly idle people seem to be when they're not actually in gyms doing something that's localised and special. You only have to look at escalators to see everyone suddenly stops walking, and you just wonder whether people have just fallen into the habit of not taking any kind of exercise if they don't have to.

Nick Wareham: I think you're right. I think we need to distinguish between exercise and physical activity. Exercise is a thing you make a volitional decision to to, you go to the gym and you do something, and I think there is probably some evidence that hasn't massively changed over time. What has really changed is probably the wider notion of physical activity which is the totality of all movement, and where it has really changed is in things like domestic life. We have a massive change in labour-saving devices in our houses. It's really changed in travel, the way we get to and from work, and also there's been a big shift in the proportion of people employed in activities that are low in energy expenditure, and really activities have been engineered out of those activities that were formally quite active.

Robyn Williams: Of course people seem to know quite a lot about what's eaten, how many calories a day...are you implying that we know very little about the amount of the energy put out per day?

Nick Wareham: I'm exactly saying that. If you ask people, 'Did you engage in vigorous activity last week? Did you go to the gym?' things like that, people know about that. What they don't know about and what's very difficult to assess in studies is the totality of physical activity, and you can't get that by asking questions. We've engineered ways of doing that with small monitors that allow us to measure that. It's very informative. When you show people how little they do in their everyday lives, many of them say, hang on, I need to make some changes here.

Robyn Williams: Do you mean those pedometers where you have something attached to your belt and you're supposed to walk 10,000 steps a day, that sort of thing?

Nick Wareham: Sure, that's one simple device that is useful for actually showing people how much or how little they do, and the target of 10,000 would be a reasonable one. For research purposes we tend to use more sophisticated instruments but the principle is the same.

Robyn Williams: Your projection is that if things remain the same...in Britain, by 2010, one-quarter of the population will be obese. Is that fair?

Nick Wareham: I think that's fair. It's probably at that sort of level already, and the question is what are we going to do about it? And I think we need to focus not just on what individuals can do but what we can do as a society, and we're beginning to see that now with the emphasis on focusing on actually collective action to encourage better eating behaviour in children, but I think that this is something that needs to be expanded for physical activity and probably to other ages as well.

Robyn Williams: A final question; some people have said that we've invented a new disease, that people were always reasonably large and that here something has been medicalised. Is that an unfair point?

Nick Wareham: No, I think it's a reasonable point actually because, at its extremes, obesity is per se a disease. The important thing from a public health perspective is that obesity is associated with coronary heart disease and particularly with type two diabetes and with many other disorders including some cancers. I think the most worrying thing about the obesity epidemic is what it tells us about what might happen in the future. So I think it would be wise of us to take action now rather than waiting until those things occurred.

Guests

Nick Wareham
MRC Epidemiology Unit Elsie Widdowson Laboratory Cambridge UK
http://www.mrc-epid.cam.ac.uk/People/nick.wareham.html

Presenter

Robyn Williams

Producer

David Fisher