Monday, April 25, 2011

Part 1: Building design to increase physical activity

We all know that we are not getting enough physical activity these days. In fact, 52% of Canadian adults 20 years of age or older are considered inactive, and 88% of children aged 5-19 years don’t meet Canada’s physical activity guidelines. It’s one out of many reasons why the prevalence of overweight and obesity is so high. But physical activity has other health benefits, in addition to staving off obesity and cardiovascular disease, such as reducing stress and improving concentration, promoting correct physical growth in children, and maintaining mobility and independence in the elderly. 

The problem is that it’s just too easy to be physically inactive.  Our society has, for all intents and purposes, engineered physical activity out of the built environment – important, especially when you consider that schools and many jobs require us to be sitting for most of the day to begin with.  Take for instance stair climbing; it is a great means of increasing cardiovascular output, but the need for it has all been eliminated by the design of modern buildings.  Escalators and elevators are easy to access and do the work for us, but are energy guzzlers - elevators account for 3-10% of a building's energy uses. Stairs, our healthy and environmentally friendly benefactor, are difficult to find, often ugly and dark, and sometimes invite anti-social activity. It’s no wonder people don’t use them.

Can we design public buildings then to increase physical activity? This is a burgeoning area of research with evaluation studies still lacking. In the next post, I’ll discuss some recommendations made by the City of New York in their Active Design Guidelines, based on the best available evidence and best practices.  However, I’d like to discuss here point-of-decision prompts as a way to get people to use the stairs instead of escalators and/or elevators – a bit different than design per se but related and still very relevant and interesting.  I was actually pleasantly surprised to see that there was a large enough body of research to warrant a systematic review on the subject.

Motivational sign from Kino Québec (not sure why the guy is blue).  More info is available at: 

This very recent systematic review was published in the Scandinavian Journal of Public Health in 2010 and included 25 studies that examined the role of posters (n = 16), stair-rise banners (n = 5), both (n =4), or posters and floor graphics (n = 1) in helping people decide to take the stairs versus elevators (n = 8) or escalators( n = 18).  The majority of studies were conducted in public transit stations (e.g. train, bus, airport), shopping malls, or office buildings.  All used the interrupted time-series design (before-after where the ‘before’ sample does not necessarily contain the same individuals as the ‘after’ sample).               

Of the 42 comparisons (more than one comparison often conducted in a study), 31 reported modest but significant increases in stair climbing, 10 reported no association, and 1 reported an inverse association. The non-significant results were more likely to be reported by studies examining stairs versus elevators. There were no consistent differences between men and women. Of the significant studies that calculated odds ratios, those in favour of the intervention ranged from 1.05 – 2.93. Results appear promising with perhaps more work to be done to get people to use stairs instead of elevators versus escalators.  

Motivational sign from NYC Active Design Guidelines

There are some important things to keep in mind about this review and the included studies:
  • Follow-up times were fairly short (at most 6 months). Some studies found that stair climbing decreased back to baseline over time (I guess as the novelty wore off)  
  • I’m not certain as to how denominators were calculated at the ‘point-of-decision’. This was not discussed in the review but likely easy to find out by accessing individual articles  
  • Only studies that looked at stair ascent were included. I think descent is equally important  
  • It’s not readily apparent which messages and/or mediums work best 
  • The same authors conducting different studies make up a large proportion of the included studies. This appears to happen in 4 instances and amounts to 16/25 studies.  This increases the likelihood of a bias occurring in one study being replicated in another, and both (or in some cases 6) being included in the review 
  • Finally, as I alluded to earlier, the study designs are methodologically weak. The authors of the review recommend a control-site but comment on the difficulties of making this happen in practice.  In my opinion, stronger designs are more difficult in public transit buildings and malls – but feasible in office buildings (e.g. randomizing buildings and following the same people within each building). 
Point-of-decision prompts look like promising ways to get people to take the stairs (another review came to similar conclusions) but I think that more high quality research is warranted.  Additionally, what if point-of-decision prompts were accompanied by changes in actual building design? You’ll have to read my next post to find out. Stay tuned.

Nocon M, Muller-Riemenschneider F, Nitzschke K, & Willich SN (2010). Increasing physical activity with point-of-choice prompts -- a systematic review Scandinavian Journal of Public Health, 38, 633-38