Boris bikes: health benefits outweigh risks from injury and pollution

shutterstock_63541750The London cycle hire scheme has had a positive overall effect on the health of its users by increasing physical activity within the capital. These benefits outweigh the potential negative impacts from injuries and exposure to air pollution, according to the results of a large-scale modelling study published today in the BMJ.

The scheme has been used far more by younger than older adults and by men than women. The research found that men and the relatively few older cyclists (45 and older) who use the scheme achieve the most pronounced benefits, while women and younger riders do not benefit as much.

The study authors suggest that reducing the injury risks cyclists face, as well as encouraging greater use of the scheme among older people, would further amplify the health benefits. The research was funded by the Medical Research Council (MRC) and National Institute for Health Research (NIHR), and through the UK Clinical Research Collaboration.

Physical inactivity has been linked previously with a wide range of health problems including heart disease, stroke, diabetes, dementia, depression and many forms of cancer. Research suggests that most people in London would benefit from increasing their activity levels and cycling offers a good opportunity to integrate this activity into everyday life. Public bike sharing schemes, like London’s ‘Boris bikes’, have been implemented in over 600 cities in 49 countries. However, to date there is only limited evidence on the health effect of these schemes.

MRC researchers, in collaboration with the London School of Hygiene and Tropical Medicine and UCL, assessed the London cycle hire scheme using a computer model that weighed up changes from physical activity, injuries and exposure to air pollution over one year (April 2011- March 2012). They used data from every journey made on a hire bike during this period, combined with information from surveys of cycle hire users and data on travel, physical activity, road traffic collisions and air pollution in central London.

The team compared the effects of the cycle hire scheme against the likely mode of transport (tube, bus, walking, etc) if the cycle hire scheme did not exist. They looked at two scenarios for injury rates – from reported accidents and injuries among cycle hire users, as well as background rates of injuries and deaths among all cyclists in central London (including those with their own bikes). They determined health benefits using a measurement called Disability Adjusted Life Years (DALYs) – the number of years of life lost to illness, disability or premature death.

The benefits of the cycle hire scheme substantially outweighed the harms when weighed against observed injury rates for hired bikes. When injury rates for all cycling in central London were used as a comparison, the benefits were smaller and disappeared entirely for women (largely due to higher death rates among female cyclists following collisions with HGVs in London). This difference reflects a trend towards lower injury rates on the cycle hire bikes than for cyclists in general in the area covered by the scheme.

Senior author Dr Anna Goodman, an NIHR Postdoctoral Fellow at the London School of Hygiene and Tropical Medicine, said: “When the cycle hire scheme was introduced, there were widespread concerns that increasing the number of inexperienced cyclists in central London would lead to higher injury rates. Our findings are reassuring, as we found no evidence of this. On the contrary, our findings suggest that the scheme has benefited the health of Londoners and that cycle hire users are certainly not at higher risk than other cyclists.”

However first author Dr James Woodcock, an MRC Population Health Scientist from the UKCRC Centre for Diet and Activity Research, which is based in the MRC Epidemiology Unit at the University of Cambridge, cautions: “We also found that the health benefits were not as pronounced in younger adults, particularly the under-30s. One reason for this is that many of the diseases affected by physical activity, such as heart disease, are less common in younger people. Even though older adults might be more at risk of injury than younger adults, the benefits from being active increase much more quickly.

“Reducing road traffic danger is another key factor. If cycling in central London was as safe as in cities in the Netherlands, the health benefits from initiatives like the cycle hire scheme would be far more substantial. The Netherlands manages to achieve high levels of cycling with low risks, not by focusing on helmets and hi-vis, but by providing high quality infrastructure that physically protects cyclists from busy, fast moving traffic.”

Dr Janet Valentine, Head of Public Health & Ageing at the MRC, said:  “The health benefits of regular exercise are undisputed. It is important that we conduct rigorous scientific studies to assess the wider impacts of interventions designed to promote health. Studies like this, which look at large amounts of data from real-world scenarios, will help to develop future strategies to bring about positive changes to our health.” 


  • Read the full BMJ paper: Health effects of the London bicycle sharing system: health impact modelling study. BMJ, 2014;348
  • For interviews with Dr James Woodcock and Dr Anna Goodman, please contact Hannah Isom in the MRC press office on 0207 395 2345 (out of hours: 07818 428 297) or email
  • In 2013, there were approximately 600,000 bicycles across 636 schemes in 49 countries
  • During the year of the study period, more than half a million (578,607) users made 7.4 million trips on London cycle hire bikes. These trips would otherwise have been mostly made on public transport (47%) or by foot (31%). Almost three quarters (71%) of cycle time was by men.
  • The London Cycle Hire Scheme was launched in 2010. It operates 24 hours a day, 365 days a year and initially comprised 5,000 bicycles across 315 docking stations in London. Following an Eastern extension in March 2012, the scheme comprised 8,000 bikes across 571 stations.  Still more recently, in December 2013, the scheme expanded to cover more of Southwest London, and currently comprises around 10,000 bikes across 723 stations.
  • The contribution of James Woodcock (first author), was funded by the MRC and the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence.  The contribution of Anna Goodman (senior author) was funded by Research Fellowship award from the National Institute for Health Research (NIHR). The contribution of Oliver O’Brien and James Cheshire was funded by the Economic and Social Research Council.
  • The Centre for Diet and Activity Research (CEDAR) studies the factors that influence dietary and physical activity behaviours at a population level, develops and evaluates public health interventions, and is helping to shape public health practice and policy. CEDAR is one of five Centres of Excellence in Public Health Research funded through the UK Clinical Research Collaboration, and is a partnership between the University of Cambridge, the University of East Anglia and MRC Units in Cambridge. 
  • The London School of Hygiene & Tropical Medicine is a world-leading centre for research and postgraduate education in public and global health, with 3,500 students and more than 1,000 staff working in over 100 countries. The School is one of the highest-rated research institutions in the UK, and was recently cited as one of the world’s top universities for collaborative research.  The School’s mission is to improve health and health equity in the UK and worldwide; working in partnership to achieve excellence in public and global health research, education and translation of knowledge into policy and practice.
  • The Medical Research Council has been at the forefront of scientific discovery to improve human health. Founded in 1913 to tackle tuberculosis, the MRC now invests taxpayers’ money in some of the best medical research in the world across every area of health. Twenty-nine MRC-funded researchers have won Nobel prizes in a wide range of disciplines, and MRC scientists have been behind such diverse discoveries as vitamins, the structure of DNA and the link between smoking and cancer, as well as achievements such as pioneering the use of randomised controlled trials, the invention of MRI scanning, and the development of a group of antibodies used in the making of some of the most successful drugs ever developed. Today, MRC-funded scientists tackle some of the greatest health problems facing humanity in the 21st century, from the rising tide of chronic diseases associated with ageing to the threats posed by rapidly mutating micro-organisms.
  • The National Institute for Health Research (NIHR) is funded by the Department of Health to improve the health and wealth of the nation through research. Since its establishment in April 2006, the NIHR has transformed research in the NHS. It has increased the volume of applied health research for the benefit of patients and the public, driven faster translation of basic science discoveries into tangible benefits for patients and the economy, and developed and supported the people who conduct and contribute to applied health research. The NIHR plays a key role in the Government’s strategy for economic growth, attracting investment by the life-sciences industries through its world-class infrastructure for health research. Together, the NIHR people, programmes, centres of excellence and systems represent the most integrated health research system in the world. For further information, visit the NIHR website (