Active commuting is beneficial for healthBMJ 2017; 357 doi: https://doi.org/10.1136/bmj.j1740 (Published 19 April 2017) Cite this as: BMJ 2017;357:j1740
- Lars Bo Andersen, professor
- Department of Teacher Education and Sport, Western Norwegian University of Applied Sciences, Bergen, Norway
Physical inactivity increases the risk of many diseases such as type 2 diabetes, cardiovascular disease, and some cancers.1 Many adults are not attracted to sports and other leisure time physical activities but may be motivated to integrate physical activity into their everyday lives. Commuting by walking and cycling are such activities. In Denmark, cycling is embedded in the national culture for two reasons: it is easier to navigate cities by bicycle than by car, and taxation on new cars is punitive.
A link between cycling and health benefits has been clear for some years—my colleagues and I first reported in 2000 that all cause mortality was 30% lower in cyclists compared with non-cyclists after multivariate adjustment.2 Since then, many studies have consistently reported lower rates of cardiovascular disease,34 type 2 diabetes,5 cancers,4 and mortality6 associated with cycling compared with not cycling. Other studies have shown that walking is also associated with health benefits, including a lower risk of cardiovascular disease, type 2 diabetes, and all cause mortality.7
In one of the largest studies of active commuting to date, Celis-Morales and colleagues (doi:10.1136/bmj.j1456) analysed data from UK Biobank to investigate associations between active commuting by walking or cycling and cardiovascular disease (incidence and mortality) cancer (incidence and mortality) and all cause death.8 Among more than 250 000 adults in paid employment, they found that active commuting by bicycle was associated with a substantial and statistically significant decrease in the risk of all cause death (hazard ratio 0.59, 95% confidence interval 0.42 to 0.83), death from cancer (0.60, 0.40 to 0.90), and death from cardiovascular disease (0.48, 0.25 to 0.92) compared with passive commuting by car or public transport. Walking was also associated with a lower risk of cardiovascular disease, but the risk of cancer or all cause death was not different from that for passive commuters. Data showed a consistent graded relation, with greater benefits for longer commuting distances and for active commuting alone compared with mixed mode commuting by active and passive methods. The study is observational, and causal relations cannot be established, but results are consistent with those of randomised trials of cycling to work9 or to school,10 which report beneficial changes in cardiovascular risk factors.
To put these new findings into perspective, around 2.6% of Celis-Morales and colleagues’ sample cycled to work (n=6751). This group experienced 37 deaths. If cycling is directly responsible for a mortality reduction (and we cannot say for sure with this design), with a hazard ratio of 0.59, 63 participants would have died if they had all commuted by car or public transport. Extrapolated across the whole of England and Wales, cycling to work could save a substantial number of lives.
Walkers did not experience a lower mortality in Celis-Morales and colleagues’ study, but they did experience a lower risk of cardiovascular disease, along with other active commuters. The British Heart Foundation11 estimates the costs of cardiovascular disease in the UK to be £15bn each year. Active commuting by walking or cycling has the potential to reduce these costs substantially. Further savings in diabetes and cancer are also possible, allowing diversion of funds into projects to improve the UK’s infrastructure for active travel.
The UK has neglected to build infrastructure to promote cycling for decades and the potential for improvements to increase cycling and the safety of cycling is huge. Cities such as Copenhagen have prioritised cycling by building bike lanes; tunnels for bikes, so cyclists do not need to pass heavy traffic; and bridges over the harbour to shorten travel time for pedestrians and cyclists. Today, no car or bus can travel faster than a bike through Copenhagen.
This has resulted in cycling rates increasing by 30% in Copenhagen over the past two decades. Most other larger cities around the world and in the UK have experienced decreases in cycling rates over the same period.12 Cycling related traffic incidents in Copenhagen have decreased by roughly two thirds, probably because the new infrastructure has improved safety. Around 40% of all commuter trips in Copenhagen are now by bike. It will take decades to change commuter culture in the UK, but it is possible, and changes in commuter behaviour can occur quickly when active travel is seen as both safe and convenient.
The findings from this study are a clear call for political action on active commuting, which has the potential to improve public health by preventing common (and costly) non-communicable diseases. A shift from car to more active modes of travel will also decrease traffic in congested city centres and help reduce air pollution, with further benefits for health.
Competing interests: I have read and understood the BMJ policy on declaration of interests declare the following: none.
Provenance and peer review: Commissioned; not peer reviewed.