Will Active Commuting Solve the Obesity Crisis?Friday, September 5, 2008
Yes, we live in a society that is designed for and continues to be dependent on the automobile. This may well be an important variable in the multitude of factors that are believed to be driving the obesity epidemic (no pun intended).
So how much would active commuting (i.e. walking or biking to work) help reduce the burden of obesity?
This question was now reviewed by Roy Shephard from the University of Toronto in a paper just out in Sports Medicine.
According to Shephard, while children and adolescents prefer cycling, for adults issues of safety, cycle storage and company dress codes make walking the preferred option, particularly in North American cities, where urban design and weather conditions often do not favour cycling. Nevertheless, active transportation is more frequent in some European countries with dedicated cycle and pedestrian paths, but in most developed societies, active transportation has declined in recent years.
Attempts to increase walking behaviour in the sedentary population have had only limited success to date.
A weekly gross energy expenditure of at least 4 MJ (~1000 KCal) is recommended to reduce all-cause and cardiovascular mortality. This can be achieved by walking 1.9 km in 22 minutes twice per day, 5 days per week, or by cycling at 16 km/h for 11 minutes twice per day, 5 days per week.
When engaged in level walking, this intensity of effort may be adequate for cardiovascular benefit in older adults, but in fit young workers, it is necessary to either increase the pace or choose a hilly route in order to induce cardio-respiratory benefit; in contrast, cycling is likely to provide an adequate cardiovascular stimulus even for young adults.
Empirical data to date have yielded mixed results: a reduced all-cause and cardiovascular mortality has been observed more frequently in cyclists than in walkers, and more frequently in women and older men than in young active commuters.
More information is needed concerning the typical weekly dose of activity provided by active commuting, and the impact of such commuting on overall attitudes towards physical activity. It is also necessary to find better methods of involving the sedentary population, through both counselling and changes in urban design.
So while I have no illusions that we are going to solve the obesity epidemic by active commuting anytime soon, I for my part, am glad to see that my daily 7 KM (24 min) bike ride to and from work well exceeds the requirements for cardiovascular fitness and lower mortality (I for sure haven’t lost any weight!).