| Last week, millions of children around North America went back to school. But most didn't walk or ride their bikes. No, these days most of those kids are driven. And it's making them fat.
In fact, our suburban, car-centric society is partly responsible for the near-epidemic levels of obesity for all age groups in North America, according to recent reports in the American Journal of Public Health and the American Journal of Health Promotion.
Researchers developed a "sprawl index" to measure patterns of development in communities across the United States. Then they compared the levels of suburban sprawl with the health of 200,000 people living in those communities based on responses from a national health survey.
Their results show a startling correlation between sprawl and obesity. In fact, people living in the least dense, most sprawling communities were likely to weigh six pounds more than those living in the most dense, compact communities. There was also a strong relationship to chronic disease – those living in sprawling communities were found to be more likely to suffer from high blood pressure.
By designing decentralized suburbs with little pedestrian or bicycle access to schools, offices, shopping and recreation, we have essentially engineered physical activity out of our daily lives. For many people living in the suburbs, the car (or, more and more often, the SUV) is by far the most convenient transportation choice to daily destinations. Many suburbs lack safe bicycle or pedestrian routes. Some don't even have sidewalks.
So, while more than 70 per cent of their parents walked or rode bicycles to school, just 18 per cent of today's schoolchildren in the U.S. do the same. In fact, more than 90 per cent of all urban trips in the U.S. are by car, while just six per cent are by foot or bike.
Canadian cities are, on the whole, more bicycle and pedestrian friendly. Today, 12 per cent of our urban trips are made by foot or bike, but we still pale in comparison to the Dutch and the Germans, who walk or bike to some 40 per cent of their destinations. These European countries also have lower rates of obesity and heart disease.
The emphasis on the car is not only making us fatter, it's causing other health problems, like asthma. More cars on our roads means more air pollution, which can trigger asthma attacks and other respiratory problems. It also means more global warming, which is likely to lead to greater health problems in the future – from increased air pollution to extreme weather events and increased exposure to new diseases.
Governments want to promote healthy lifestyles, and they have budgets for public awareness campaigns to encourage people to be more active. But it's absurd and counterproductive for people to have to get into their cars and drive to the gym. According to the U.S. Center for Disease Control, simply burning an extra 100 calories per day, or 20 minutes of walking, is enough exercise to help people lose weight and curb the disturbing obesity trend.
To buck that trend, we have to re-engineer physical activity back into our lifestyles. That means redesigning our cities to be more dense and compact, with better bike paths and pedestrian-friendly walkways. It means changing development patterns so that "going out" does not always involve walking into the garage, climbing into an SUV, clicking the door opener and driving five kilometres. It means fewer strip malls with vast parking lots that are accessible only by car. It means making stairways more accessible and more attractive so people use them. It means widening sidewalks and narrowing roads. More importantly, it means cleaner air, better health, reduced global warming and a better quality of life.
Science Matters is a regular feature by writer, geneticist and television host David Suzuki. To discuss this topic with others, visit the discussion forum at www.davidsuzuki.org. |
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