The Physical Activity and Population Health BJSM Blog Series

By Sonia Cheng @soniawmcheng

The Tour de France. Lycra. Fending off swooping magpies during the Australian springtime.

Cycling is perhaps the most iconic type of physical activity of them all, and as a mode of transport, has been proposed as a potential solution to the global pandemic of physical inactivity. Yet detractors argue that cycling comes with additional costs and safety concerns, and requires an overhaul of existing infrastructure in order to be a safe and accessible means of transport for the general population. How does cycling weigh up as a strategy to increase incidental physical activity?

The headwind vs the tailwind: What are the health benefits and what are the risks?

Active commuting via bicycle is not very common in countries such as Australia or the UK, where driving remains the dominant form of transportation. In 2011, cycling represented 1% and 3% respectively of the population’s method of travelling to work^1,2.

Nevertheless, large population-based studies have shown that cycling as a mode of transport is associated with a lower risk of cardiovascular disease, cancer, and all-cause mortality, and may be a more beneficial form of commuting than walking^3,4. Getting on a bicycle and leaving the car at home has a positive societal impact too, helping to reduce air pollution and greenhouse gas emissions, and reduce traffic congestion.

Being a cycling commuter does pose some potential hazards, however. The risk of being involved in a traffic accident may increase, particularly in city centres and areas lacking supporting infrastructure – and crashes and collisions could result in injury or fatality. Cycling commuters may also be at risk of inhaling more air pollutants due to the increased breathing rates associated with physical activity. A small number of observational studies suggest that exposure to in-traffic air pollution may lead to airway inflammation and decrements in lung function in both healthy adults and those with existing lung conditions⁵.

When the benefits and risks are weighed up directly, the estimated health benefits of cycling are substantially larger than the health risks. One study showed that if 500,000 people in the Netherlands swapped their car for a bicycle for short trips on a daily basis, 3-14 months of life would be gained as a result of increased physical activity levels, compared to the smaller harmful effects of inhaled air pollution (0.8-40 days lost) and increase in traffic accidents (5-9 days lost)⁵.

Copenhagen: The world’s best city for cyclists

When Copenhageners own five times more bicycles than cars and Crown Princess Mary herself takes the kids to school in a cargo bike, you know the title of ‘world’s best city for cyclists’ is well-deserved.

Active commuting is part of the established culture in Copenhagen and can be attributed to the favourable cycling conditions in the city: dense urban proximities requiring short distances to travel, flat terrain, and an extensive and well-designed system of cycle tracks that are clearly separated from the roads by a curb.

A recent Danish report⁶on cycle related injuries and prevented morbidity/mortality revealed some impressive statistics:

• Over the last two decades, national levels of cycling in Denmark increased by 10%, but cycle related injuries have declined by 55% since 1998.
• Cycling may prevent over 6,000 deaths, 5,000 cases of cardiovascular disease and 3,000 cases of type 2 diabetes each year.
• The health benefits of physical activity associated with cycling were 21 times higher than the risk of injuries.

A two-wheeled ride off into the sunset

Cities like Copenhagen illustrate just how much can be done to increase active commuting in the general population, and we can certainly learn from their strategies to improve the safety of cycling commuters: segregated cycle lanes, bicycle hire and purchase schemes, secure parking, facilities for bicycles on public transport, to name a few.

‘The bicycle is a valuable means of transport in its own right and should be treated as such’, declares the Cycling Embassy of Denmark. And if governments and policymakers can make cycling safe, convenient and accessible – then people will ride.

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Sonia Cheng @soniawmcheng graduated from The University of Sydney with a Bachelor of Applied Sciences (Physiotherapy) (Honours Class I) in 2014. Sonia is currently employed as a physiotherapist with Royal Prince Alfred Hospital and Westmead Hospital in Sydney.

We invite you to share and support the Physical Activity and Population Health BJSM Blog Series. Join the conversation on ‘how change happens’ at #PAblogBJSM and #brightspotsBJSM. We welcome guest blogger contributions. If you have any ideas please email emmanuel.stamatakis@sydney.edu.au.

References

1. Australian Bureau of Statistics. ‘More than two in three drive to work, Census reveals’. Published 23 October 2017. http://www.abs.gov.au/ausstats/abs@.nsf/mediareleasesbyReleaseDate/7DD5DC715B608612CA2581BF001F8404?OpenDocument.
2. Goodman A. Walking, cycling and driving to work in the English and Welsh 2011 census: trends, socio-economic patterning and relevance to travel behaviour in general. PLoS One. 2013;8:e71790. doi: https://doi.org/10.1371/journal.pone.0071790.
3. Celis-Morales CA, Lyall DM, Welsh P, Anderson J, Steell L, Guo Y, et al. Association between active commuting and incident cardiovascular disease, cancer, and mortality: prospective cohort study. BMJ. 2017;357:j1456. doi: https://doi.org/10.1136/bmj.j1456.
4. Matthews CE, Jurj AL, Shu XO, Li HL, Yang G, Li Q, Gao YT, Zheng W. Influence of exercise, walking, cycling, and overall nonexercise physical activity on mortality in Chinese women. Am J Epidemiol. 2007;165:1343–50. doi: https://doi.org/10.1093/aje/kwm088.
5. Johan de Hartog J, Boogaard H, Nijland H, Hoek G. Do the health benefits of cycling outweigh the risks? Environ Health Perspect. 2010;118:1109-16. doi: https://doi.org/10.1289/ehp.0901747.
6. Andersen LB, Riisera A, Rutter H, Goenkad S, Nordengen S, Solbraa AK. Trends in cycling and cycle related injuries and a calculation of prevented morbidity and mortality. J Transport Health.2018;9:217-25. doi: https://doi.org/10.1016/j.jth.2018.02.009.