The use of the automobile for personal transportation brings considerable benefits to individuals, such as the ability to travel quickly, easily and independently over long distances. However, car travel also contributes to health problems and societal threats such as physical inactivity, obesity, air pollution, climate change, habitat degradation, oil dependence, political instability, and economic insecurity.
These problems are particularly pronounced in the USA, which currently consumes roughly 27% of global oil production and produces approximately 25% of global carbon emissions, and where roughly 65% of adults are overweight or obese. Other countries throughout the world that replicate or hope to replicate the automobile-based lifestyle of the USA face similar problems now or in the near future.
Diet, genetic makeup, culture, and politics predispose some individuals to obesity and overweight. However, weight gain or loss is determined by the balance of energy intake (eating) and energy expenditure (exercise). Therefore, increased physical activity, assuming no other changes, would translate into a loss of weight.
In a recent paper, I explored the relationships between the distances that could be travelled through recommended daily exercise by walking or cycling with weight loss, oil consumption and carbon emissions. Straightforward calculations demonstrate that an average individual who substitutes the recommended daily amount of exercise for car trips would burn 12.2 and 26.0 kg of fat per year for walking and cycling, respectively. If exercise based transportation were adopted by the population as a whole, this rate of weight loss is sufficient to eliminate obese and overweight conditions in a few years without dangerous or draconian diet plans.
At the same time, substituting exercise for car travel would reduce the USA’s oil consumption by up to 38%. This is a potential saving that far exceeds the amount of oil recoverable from the Arctic National Wildlife Refuge, suggesting that exercise can reduce foreign oil dependence and provide an alternative to oil extraction from environmentally sensitive habitat.
Finally, if the savings on health care that result from increased physical activity were applied toward reducing the risks of climate change—roughly US$ 117 billion is spent annually in the USA on health care for obesity and overweight health problems alone—a reduction in carbon dioxide emissions of roughly 35% is possible. Of course, alternative uses for any health care savings may make sense.
These are highly simplified calculations, of course, that overlook significant barriers to the adoption of exercise-based transportation. For example, given the option to drive, people are often reluctant to walk or cycle even short distances under ideal conditions. Poor health, disability, weather, time of travel and previously developed infrastructure all pose additional obstacles to the substitution of exercise for driving. Furthermore, driving distances are unequally distributed throughout the population and many individuals do not drive sufficiently far (or even at all). This makes the assumption of substitutability of driving questionable in some cases.
On the other hand, urban planning could facilitate a transportation approach that combines public transportation with exercise and that offers even greater potential for reaping co-benefits. For example, individuals could walk or bike short distances to bus or train stops and then take mass transit for much longer distances. This would amplify the potential to reduce oil dependence and carbon emissions.
Most importantly, these calculations appear to contradict three widely-held views: (1) meeting current and future energy needs requires either extraction or technological development, (2) addressing the threat posed by climate change requires social and economic sacrifice, and (3) dieting constitutes the most effective weight-loss strategy. Instead, exercise based transportation offers a favorable alternative to the energy and diet plans that are currently being implemented in developed countries like the USA and may lead policy-makers to better development choices in developing countries.
For individuals, these calculations illustrate that by integrating exercise into daily our lives, we can dramatically improve our physical activity and health and help solve several of today’s most challenging social problems. Given the crushing burden of obesity on individuals and society, we need to tap all potential sources of motivation.
This post is adapted from: Higgins, P.A.T. 2005. Exercise based transportation reduces oil dependence, carbon emissions and obesity. Environmental Conservation. 32(3):197-202.