Abstract
Objective To review the literature about cycling and health, and to provide an overview and discussion of the available evidence.
Sources of information The MeSH terms bicycle and transportation were searched in PubMed. Clinical trials, practice reviews, and systematic reviews were included. All reference lists were reviewed for additional articles.
Main message Climate change is a threat to health. In Canada alone, transportation is the second largest source of greenhouse gas emissions. Active transportation, which is any form of human-powered transportation, can mitigate the health effects of the climate crisis while simultaneously improving the health of people. Physical activity improves overall well-being, as well as physical and mental health. Active transportation, particularly cycling, is a convenient way to meet physical activity targets, reduce risk of disease and all-cause mortality, and derive mental health and social benefits. Family physician advocacy for active transportation has been shown to increase cycling levels in patients compared with no physician advocacy.
Conclusion Family physicians can help to increase the level of active transportation at the individual patient level through patient education and behaviour change counseling; at the community level through community education and political advocacy; and at the policy level through partnerships with larger organizations.
Case description
A 48-year-old male in your practice, Mr B., underwent primary percutaneous coronary intervention last month for non–ST-segment elevation myocardial infarction. He is feeling quite well and is here for follow-up. He has 2 school-aged children and a busy law practice. Recently, his children have been expressing anxiety about the environment after learning about the climate crisis at school. At previous periodic health reviews, Mr B. told you that he is too busy to exercise. Mr B. now states, “I know exercise is important to prevent another heart attack, but I still feel like I have no time. How can I do everything I need to do to stay healthy?”
Sources of information
The authors performed a literature search on cycling and health. The MeSH terms bicycle and transportation were searched in PubMed. Clinical trials, practice reviews, and systematic reviews were included. All reference lists were reviewed for additional articles.
Main message
Cycling and the climate crisis. The World Health Organization has called climate change the biggest health threat of this century.1 Climate change has a range of direct and indirect physical and mental health effects, including increased heat-related illness; worsening lung and heart disease from increased air pollution; direct injury and displacement from floods, droughts, and other extreme weather events; and increased food insecurity.1 As family physicians, we can do more to help mitigate climate change and preserve our planet.2 Tackling climate change has also been called “the greatest global health opportunity of the 21st century”3 through the health co-benefits of mitigation.4
In Canada, transportation is the second largest source of greenhouse gas emissions, accounting for 25% of total emissions.5 Private automobile use accounts for about half of all transportation-related emissions.6 Active transportation, which is any form of human-powered transportation,7 can mitigate the health effects of the climate crisis by decreasing transportation-related emissions. A recent study that used travel activity data from 7 European cities found that those who switch 1 trip per day from car driving to cycling reduce their carbon footprint by about 0.5 metric tons per year. Thus, if 10% of the population were to change their travel behaviour, the emissions savings would be around 4% of life-cycle carbon dioxide emissions from all car travel.8
Cycling is a reliable, convenient, and efficient form of transportation. In Canada, the percentage of bicycle commuter trips varies from 1% to 3%,9 while in Europe, cities with extensive cycling infrastructure reach levels of 40%.10 Physicians can both promote cycling as a viable mode of active transportation to their patients and advocate for safe cycling infrastructure to their community leaders.
Health co-benefits of cycling. In addition to mitigating the health impacts of climate change by reducing greenhouse gas emissions, there are direct health benefits of cycling. Physical activity improves well-being; allows for prolonged independence as we age; prevents development of chronic diseases such as diabetes, coronary artery disease, and depression; and decreases all-cause mortality.11 Yet, Canadians do not get enough exercise: only 16% of adults meet the recommended activity target of 150 minutes of moderate to vigorous physical activity per week.12
Active transportation provides a convenient way for people to meet physical activity targets, all within the framework of their daily commute.13 Cycling for transportation is an excellent form of exercise,14 and a recent systematic review of randomized controlled trials has shown that switching to active commuting can increase physical activity levels and physical fitness.15 The effect is similar in children.16 One study showed that commuting a distance of 3 km by bicycle was enough to lead to a statistically significantly increase in physical fitness.17
Large cross-sectional observational surveys have shown that active commuting is statistically significantly and independently associated with a reduction in risk of cardiovascular disease, cancer, and all-cause mortality,18-26 which has been confirmed in a recent systematic review.27 Several recent randomized controlled trials have confirmed similar results.21,28,29
Three studies have concluded that the benefits of physical activity from active transportation outweigh the risks of air pollution exposure in most scenarios.30-32 In fact, a systematic review of 39 studies investigating the relationship between transportation mode and air pollution exposure concluded that motorists consistently experience the highest exposure to air pollution.33
Cycling for transportation may also have important mental health benefits. Some studies have demonstrated a decrease in depression symptoms,34,35 while others have demonstrated an overall increase in emotional well-being and happiness.36,37
Cycling as active transportation has shown to have indirect benefits for health. A study showed that an increase in bicycle use and a reduction in car use reduces air pollution,38 which is a major cause of respiratory and cardiovascular disease.39,40 Xia et al reported that a reduction in traffic-related air pollution decreases disability and death from asthma and heart disease,41 and can help mitigate climate change in the future. Noise pollution has also been directly linked with decreased quality of life,42,43 and will likewise decrease with a decrease in motorized traffic.44,45 Finally, time spent sitting in a car is directly associated with poor health outcomes, including obesity and cardiovascular disease46; less time spent behind the wheel and more time spent on 2 wheels will lead directly to better health outcomes.14-29
Cycling also has substantial social benefits. Car ownership can be expensive; the average household in Canada spends a large proportion of its income on private vehicles and fuel.47 Extensive and safe cycling infrastructure can enable inexpensive travel around cities.48 Walkable and bikeable neighbourhoods foster social interaction and community cohesion. Findings from a systematic review on the built environment and health indicate that neighbourhoods that are more walkable are associated with increased physical activity, increased social capital, lower rates of obesity, lower reports of depression, and less reported alcohol use.49
Role of family physicians. Family physicians can help to increase the level of active transportation in our patients and communities in a number of ways. We can act at the micro or individual patient level, the meso or community level, and the macro or policy level.50 As family doctors, we are experts at intervening with individual patients. We are also obligated to advocate for strategies that can prevent illness and injury, and to engage in community health promotion.51
At the micro level, we can encourage our patients to ride bicycles as a form of exercise. We can work with our patients to overcome individual barriers to cycling using techniques such as motivational interviewing.52,53 A systematic review found that physician intervention to encourage cycling for transportation statistically significantly increased cycling levels compared with placebo intervention that did not involve physicians.54 Another review found that written interactive materials, including local maps; local bicycle retailers; and reflective safety accessories can lead to an increase in active commuting behaviour, especially when provided in tandem with improved cycling infrastructure.55
Encouraging active transportation can be understood as a form of social prescribing. A 2012 systematic review confirmed that brief primary care–based interventions promoting physical activity are effective in improving self-reported physical activity at 12 months, with a number needed to treat of 12.56 A recent Tools for Practice update57 confirmed that physical activity prescriptions, combined with patient-specific goals and monitoring, may increase physical activity levels by up to 1200 steps per day at 1 year, with an additional 1 person becoming active for every 10 prescribed activities compared with general advice alone.
At the micro level, we can also educate our patients on the individual health impacts of the climate crisis and the importance of mitigating climate change to promote health.58 A toolkit developed by the Canadian Association of Physicians for the Environment includes several patient handouts that might be useful in discussing the negative health effects of the climate crisis.59
At the meso level, family physicians can educate the public and our communities about the aforementioned extensive health benefits of cycling. Family physicians can also encourage our clinics and hospitals to provide bicycle parking and infrastructure for staff who choose to cycle to work, thereby serving as models for their community in using active transportation. The Green Office Toolkit provides further suggestions for reducing transportation-related emissions in clinics and hospitals.60
At the macro level, physicians can advocate for policy changes that increase cycling safety and increase the number of cyclists. Several systematic reviews of the health impact of transportation interventions show that the implementation of a robust network of separated bike lanes can increase levels of cycling and fitness.61-64 There is also limited evidence that removing street parking62 and implementing bike share programs may help improve cycling levels and fitness.65
Family physicians can advocate for safe cycling infrastructure in our neighbourhoods and communities by collaborating with local cycling advocacy and road safety groups, meeting with local city councillors, and engaging with local media. In 2017, several of the authors formed a group called Doctors for Safe Cycling with the goal of advocating for better cycling infrastructure in Toronto, Ont.66 Policy makers are very interested in hearing from physicians about health and safety issues, and our advocacy work can have an effect on local planning and policy.67 Family physicians are the most trusted source in their communities on environmental health issues,68 specifically climate change,69 and we can use that trust to bolster the work of other organizations that are working to support healthy communities. Partnering with other advocacy groups can lead to productive and effective advocacy work. We can also encourage our provincial and national organizations, including the College of Family Physicians of Canada, to advocate for safe cycling infrastructure.
Case resolution
Using motivational interviewing techniques, you suggest that Mr B. consider a form of active transportation to get to work. Mr B. normally drives to the commuter train station, but agrees to consider cycling to the train station, at least on nicer days. You provide him with additional information on the link between the climate crisis, exposure to air pollution, and exacerbation of heart disease to the benefits of active transportation. He is pleased that he can model climate action for his children. Inspired by Mr B.’s case, you also write to your local city councillor, highlighting the need for safer cycling infrastructure in your suburban community.
Conclusion
While many of the changes we must make to our society in order to mitigate the climate crisis require difficulty and compromise, increasing the level of cycling in our communities has been shown to be beneficial for both the environment and population health.
Notes
Editor’s key points
▸ Climate change has many negative physical and mental health effects, such as increased heat-related illnesses, worsening lung and heart disease, and injury from natural disasters. In Canada, greenhouse gas emissions from transportation account for a large proportion of total emissions.
▸ Active transportation—any form of human-powered transportation— can mitigate the detrimental health effects of climate change by reducing transportation-related greenhouse gas emissions. Cycling in particular has been shown to reduce carbon footprints, improve overall well-being, prevent chronic diseases and all-cause mortality, reduce noise pollution, and foster social interaction.
▸ Family physicians can both encourage active transportation and mitigate climate change by advocating for increased cycling levels in patients, by promoting safe cycling infrastructure in communities, and by collaborating with policy makers in governments.
Footnotes
Contributors
All authors contributed to the content of this manuscript and approved the final version for submission.
Competing interests
None declared
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This article has been peer reviewed.
La traduction en français de cet article se trouve à www.cfp.ca dans la table des matières du numéro d’octobre 2021 à la page e280.
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