Forget all the other reasons you should be riding a bike. This is the one that matters

A new study offers perhaps the most definitive reason yet why society should be doing more to encourage cycling, and serves as another reminder that the health benefits of cycling far outweigh the risks.

This British study took a comprehensive look at the health benefits of bicycle commuting, and the results are staggering. Over the course of the study, the 263,450 subjects who were under review had a 41 per cent lower chance of death than those who didn’t. “Cycle commuters had a 52 per cent lower risk of dying from heart disease and a 40 per cent lower risk of dying from cancer. They also had 46 per cent lower risk of developing heart disease and a 45 per cent lower risk of developing cancer at all,” the study’s authors wrote.

Vancouver cycling

Bicycle commuting has major health benefits that far outweigh its risks. Photo: Tom Babin.

Just let those numbers soak in a bit. They truly are significant. If a pharmaceutical company created a pill that could reduce your chance of dying by almost half, with particular success against those stubborn scourges of humanity of cancer and heart disease, it would be heralded as a wonder drug. Luckily, this pill is already hanging from the rafters of your garage.

Two things struck me particularly from the study.

In their analysis, the researchers accounted for the risk associated with road accidents, which offers further evidence that even the supposed risks of riding a bike are vastly outweighed by the benefits of riding. Put another way: Our irrational fear of the relatively small risk of a blow to the head is overriding the guaranteed health benefits of bicycle commuting. Our assessment of risk in this context is, to be blunt, pretty messed up.

This mirrors the message of this new Australian documentary arguing against the country’s mandatory helmet law. In it, public health doctors and advocates express the same message: the health benefits of cycling far outweigh the risk of injury, so we should be doing more to make it easier to ride bikes daily for transportation.

Which leads me to the second aspect of the study that really caught my attention. Of most benefit here wasn’t just riding a bike, but bicycle commuting. This is a pretty significant distinction.

That distinction is the difference between encouraging people to get out and exercise and making it easier for people to simply use a bike in their everyday lives. The medical community has been encouraging us for nearly a century to do the former, and despite the mainstreaming of things like running and going to the gym, we keep getting more sedentary, more obese and more unhealthy. That approach to health isn’t exactly a ringing success.

But this study seems to be mirroring what many cycling advocates have long said, and what bike commuters preach about all the time: Active living works when it’s part of our day, not an add-on.

The study found most of the benefits from cycling come in those situations in which cycling has already been built into the daily lives of people. In the world’s great bike cities, for example, people don’t bike because it’s good for them any more than they bike because it improves the street life of the city or because, God forbid, it reduces their carbon footprint. If you ask them, they will tell you that they ride a bike because it’s quick and easy.

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Bicycle commuting, in particular, was found to have major health benefits far beyond recreational cycling. Photo: Tom Babin.

“Policies designed to affect a population level modal shift to more active modes of commuting, particularly cycle commuting (eg, cycle lanes, city bike hire, subsidised cycle purchase schemes, and increasing provision for cycles on public transport), present major opportunities for the improvement of public health,” according to the study’s conclusion.

Therein lies the solution. If we want society to realize that 41 per cent improvement in our health that comes with bicycle commuting, we need to make it fast and easy to get places on a bike. That means continuing to accommodate bikes on our streets and building cities around the idea of active transportation. We’ve already started in most cities. We just need to hurry up.


Also published on Medium.

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19 Comments

  1. Geoff McLeod

    I made this film to help people see that there are many different forms of cycling and many different benefits to using a bicycle, with health being the main one. As the Australian experience shows, a one-size-fits-all helmet law can do more harm than good in public health.
    I hope it helps policy makers everywhere to understand that is always better to make it safer to ride instead of laws making it safer to crash.

    • Thanks for taking the time to comment, Geoff. Your film makes some great points, particularly about our failure to recognize the differences between different types of riding. Even in places without a mandatory helmet law, the film has much to teach us. Here’s my take on helmet use in my cycling life: http://shifter.info/most-of-the-time-i-ride-a-bike-i-wear-a-helmet-but-not-always-heres-why/

    • Tony

      I have been riding for over 15 years about 100 k’s per week. I have come off 8 times , 6 of those my head has hit the road or a post.
      I would probably not still be riding if I had not worn a helmet.
      I will continue to ride my bike WITH a helmet

      • Frank Krygowski

        You’re almost certainly mistaken if your “.. if I had not worn a helmet” was supposed to mean you would have suffered serious or fatal Traumatic Brain Injury (TBI).

        It’s very common to believe a scratched, dented or broken helmet is proof that a serious brain injury was prevented. But it’s a false belief. Every year there are vast numbers of such claims, but there has never been a corresponding drop in bike fatalities. Since helmets became popular, pedestrian fatalities have fallen faster than bicyclist fatalities; there is no apparent helmet benefit in that data. From 1997 to 2011, despite growing helmet use, bicyclist concussions rose more than 60%. There is no apparent helmet benefit in that data either. And even Tour de France racers rarely used helmets until forced to in recent years, yet had no greater TBI count than today.

        There’s been considerable speculation why the “it saved me!” tales don’t correspond with drops in TBI. Some studies have shown that people with helmets are more likely to crash and hit their heads, whether its because they feel protected and are therefore less careful (i.e. “risk compensation”), or simply because a helmet is a larger target than a bare head. In other words, perhaps helmets convert many near misses of bare heads into helmet impacts. Surely, if one wore styrofoam clown shoes for a few days the cracks and dents would soon “prove” they saved your feet dozens of times!

        In any case, an impartial evaluation of data shows that ordinary bicycling imposes no great risk of serious TBI. Bicyclist comprise only 0.6% of the fatal brain injuries in the U.S. (Walking and riding in motor vehicles are much bigger sources, and pedestrians are at much higher risk per mile traveled.) Whether one is worried about TBI or worried about other other serious injuries, cycling is NOT an excessively risky activity. Every study ever done on the issue has found cycling’s benefits greatly outweigh its tiny risks. And as Chris Boardman has said, helmets are not even in the top ten list of ways to make cycling safer.

  2. Lee

    I took a scanning look at the study. I did not see that the participants were randomly selected to be active…or indolent. Which of course would be needed for a relevant study . It is most probable that those who rode bikes were more active & fit in the first place and conversely those who did not ride bikes or were more indolent…were less fit or had some underlying problem that influenced their lack of activity. Self selection does not make a study.

    • Good questions to ask. From the author’s piece linked to above: “We looked at 263,450 people with an average age of 53 who were either in paid employment or self-employed, and didn’t always work at home. Participants were asked whether they usually travelled to work by car, public transport, walking, cycling or a combination.

      “We then grouped our commuters into five categories: non-active (car/public transport); walking only; cycling (including some who also walked); mixed-mode walking (walking plus non-active); and mixed-mode cycling (cycling plus non-active, including some who also walked).

      “We followed people for around five years, counting the incidences of heart disease, cancers and death. Importantly, we adjusted for other health influences including sex, age, deprivation, ethnicity, smoking, body mass index, other types of physical activity, time spent sitting down and diet.”

      • Anonymous

        what do you say now Lee?
        booya

      • Lee’s right. This is an observational study (as opposed to a randomized controlled trial), and estimates of causal effects with observational data are likely to be biased. The fundamental problem is that people who chose to cycle to work are probably different–along other health dimensions relevant to the outcome variables–than those who drive. Unless you control for every one of those relevant health dimensions, you’ve introduced a source of bias. Note that the study authors repeatedly say “cycling is associated with…” rather than “cycling causes…”. That’s their way of essentially admitting they can’t draw the conclusions that Tom’s drawing. The authors even write “associations may not imply causation” and “the findings, if causal…” near the end of the paper. Sure, they control for a bunch of relevant stuff, but they even admit that they don’t control for overall non-commuting physical activity. That’s a huge omission and could cause huge bias. The way to do this study right is to find something that randomly assigns people to bike or drive and make comparisons of health outcomes across those groups.

        • Frank Krygowski

          It’s true the study didn’t deal with randomly selected subjects, since that would be practically impossible. And yes, it wasn’t a gold-standard double blind study, because that too would be practically impossible.

          OTOH, there have been at least five studies that I know of that have attempted to determine the benefit to risk ratio of cycling (not necessarily cycle commuting). In each case, using different metrics and different techniques, the study found cycling’s benefits far outweighed its tiny risks. The lowest ratio I’m aware of was 7:1 in favor of cycling. The highest I know of was 77:1 in favor of cycling.

          • Wouldn’t surprise me if each of those studies was subject to a similar criticism, since it’s hard to randomize whether people commute by bike (or ride bikes, exercise, whatever). Would be nice if someone found some good, naturally occurring, random variation in commute choice to exploit. That would probably give us a more reliable estimate of the causal effect. Until then, we should be cautious making empirical claims about causal effects. The problem with bad science is that it tends to tarnish all science–including the well-done studies.

        • jay

          Even a randomized control trial would be biased -as people randomly assigned to the cycling condition would likely drop out at a higher rate than the other conditions because cycling can be difficult/scary for inexperienced people. Nevertheless, they did statistically control for all of the variables that could plausibly produce such a large health effect:

          “Analyses were adjusted for sex, age, ethnicity, Townsend deprivation index, comorbidities (longstanding illness, diabetes, hypertension, CVD, cancer, and depression), body mass index (coded as categorical variable based on the World Health Organization classification19), smoking, dietary intake (alcohol, fruit and vegetable, red meat, oily fish, poultry, and processed meat), time spent walking for pleasure, time spent undertaking strenuous sport, time spent in light and heavy DIY, level of occupational physical activity, and sedentary behaviour.”

          • Attrition bias is a common problem with randomized controlled trials (also with panels of observational data). But it’s easier to adjust for (or put bounds on) than omitted variables bias. The following quote is from the authors of this paper:

            “Additionally, fitness and objectively measured physical activity was only available for a subset of the cohort with active commuting data, which limited the possibility of adding these variables as covariates in our models. We adjusted for occupational physical activity and some aspects of leisure time physical activity (walking for pleasure, strenuous sport, and DIY), but do not have a measure of overall non-commuting activity, so may not have fully adjusted for potential contributions of non-commuting physical activity on the measured health outcomes.”

            So they didn’t control for “all of the variables…” And then there’s any other determinant of mortality that happens to be correlated with commuting by bike and that they didn’t have data for (there could be dozens). And the fact that health might actually be driving the bike commuting decision, rather than the reverse causal direction assumed (without discussion) by the authors.

  3. Kevin Dale McKeown

    A very inspiring commentary on a valuable study, spoiled only by the author’s poor choice of words in the second paragraph, repeated subsequently:

    “… subjects who were under review had a 41 per cent lower chance of death than those who didn’t.”

    Sorry folks, but every one of us has a 100 per cent chance of death.

    I know it’s a picky point, but as an editor that’s what I specialize in. Tighten it up!

    • Thank you for the editing! But if you read the entire sentence, I think it holds up. The operative phrase is at the beginning: “Over the course of the study…”

  4. stephanie Peppard Post

    I am from Dublin Ireland and had been commuting to work by bicycle for approx 40 years (I am a nurse working in a busy city hospital and am now 60) I have never fallen off my bicycle and NEVER worn a helmet. I cycle on my holidays on my own bike or sometimes on a rented bike (depending on where I am… my most recent bike rental was when I went to San Fransisco). Recently, for family reasons, I moved further into the countryside, sadly too far to commute by bicycle but I cycle still on summer evenings and every weekend. I will continue to cycle without a helmet even if they make it a law here (Can’t imagine the farmers here complying when they head down to road to bring in the cows).

  5. Martin Cornish

    I live on the Gold Coast that has universal mandatory helmet laws and working in Darwin where you are allowed to ride on bike tracks without a helmet. I prefer the Darwin way . It is just great getting on a bike and riding somewhere without having to stick on a helmet. People just use common sense . The ones going very fast tend to wear helmets even though they don’t have to because they know they have a much higher risk of crashing than the rest of us. Bike sharing is harder when you have to wear helmets. Years ago a mate of mine with a beer gut lost his drivers licence and had to commute to work by pushbike resulting in his beergut disappearing very quickly. He had changed nothing else in his lifestyle. I am 100 per cent behind making the world bike friendly.

  6. Aaron Ure

    I am from Cambridge New Zealand, we have an increase in the use of Trikes here and I am loving it. A trike rider myself I am constantly in touch with older folk who wont to give it a go but the helmets and costs are a draw back. For the speed that most cyclists move at, two or three wheel, a helmet makes little difference.
    The problem comes with sharing a road that is designed for larger-faster transport. The pace of society dictates that we wont to do everything now, a two minute noodle generation, and life is actually enriched by taking time not racing from one place to another.
    Looking at the wider problem we have local councils creating new roads that are barley wide enough for two vehicles with parking on one side, let alone making space for cyclists as well. I say lets create wider shared pathways and dedicated cycle roads that by pass the main traffic and high accident areas.

  7. @ Martin: Although it’s been a while since I read other studies of benefits vs. risk of cycling, I recall that several if not most of those studies arrived at their conclusions by computation, using previously determined data. For example, there’s decent data on the frequency of bike crashes and the distribution of the magnitude of injuries; on the effects of air pollution exposure; on the risks motoring imposes on pedestrians; on the benefits of exercise, etc. In at least some of the studies, these factors and many others were combined mathematically to arrive at benefit vs. risk ratios for cycling.

    Also, the criteria and affected populations varied, with some examining only the cyclists, others examining the entire affected population (since pollution affects bystanders, motor vehicles kill pedestrians, etc.). For criteria, some studies used years-of-life gained vs. lost, others used medical expenses incurred vs. saved, etc. In those studies, the research itself did not need to randomly select cyclist subjects, since the existing data applied to (e.g.) anyone getting exercise, or anyone breathing pollution.

    The significant point is that despite variations in methodology and criteria, _every_ study done on this question (AFAIK) found by large margins that bicycling was a net health and societal benefit.

    And the importance is this: A great many people believe that bicycling is a terribly risky activity unless done only on special facilities while using unusual protective equipment. But that idea is false. Ordinary bicycling is extremely beneficial both for those who choose to bicycle and for those who are thereby subjected to less risk from auto use. On balance, it’s not an activity that should be considered “dangerous.” It should be promoted.

  8. R. L. Skylark

    The attached study points out that the longevity of healthier people may burden an already overpopulated environment. http://opim.wharton.upenn.edu/~ulrich/documents/ulrich-cycling-enviro-may06.pdf

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