# Does wearing a bicycle helmet really not effect the head? **URL:** \ **Category:** Factual Questions\ **Created:** [December 10, 2016, 6:18pm UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366 "2016-12-10T18:18:12Z")\ **Posts on this page:** 20\ **Page:** 5
**Author:** ![Turble](https://avatars.discourse-cdn.com/v4/letter/t/8dc957/32.png) [@Turble](https://boards.straightdope.com/u/Turble)\ **Post date:** [December 14, 2016, 3:14am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/81 "2016-12-14T03:14:37Z")
> [@Riemann](#): > > I’d also like to see evidence for your earlier claim that pro cyclist injury and death rates are worse since mandatory helmets were introduced for racing. Here you go; helmets became mandatory in 2003 and the difference is very clear – used to be years between the deaths of pro cyclists during a race, now it rare for a year to go by without at least one and maybe more. [Cyclists who died due to a race](https://en.wikipedia.org/wiki/List_of_cyclists_with_a_cycling_related_death) ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [December 14, 2016, 3:28am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/82 "2016-12-14T03:28:49Z")
> [@Turble](#): > > Here you go; helmets became mandatory in 2003 and the difference is very clear – used to be years between the deaths of pro cyclists during a race, now it rare for a year to go by without at least one and maybe more. > > [Cyclists who died due to a race](https://en.wikipedia.org/wiki/List_of_cyclists_with_a_cycling_related_death) Yes, that site was the first thing I found when I saw your claim further upthread. How are you interpreting that to show more deaths since mandatory helmets? ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [December 14, 2016, 3:39am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/83 "2016-12-14T03:39:01Z")
> [@Turble](#): > > Here you go; helmets became mandatory in 2003 and the difference is very clear – used to be years between the deaths of pro cyclists during a race, now it rare for a year to go by without at least one and maybe more. > > [Cyclists who died due to a race](https://en.wikipedia.org/wiki/List_of_cyclists_with_a_cycling_related_death) 21 deaths between 2003 and present. 1-no helmet 6-heart attacks 1-collision with 18 wheeler 3-vehicle collision 1-blunt force trauma to chest 1-high speed on decent ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [December 14, 2016, 4:36am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/84 "2016-12-14T04:36:40Z")
Interesting how helmets have increased the number of heart attacks occurring during bicycle races too. Of course what is missing is the denominator. Competitive cycling exploded over that time frame. Amazingly when the denominator is included [the rate of serious injuries is unchanged](http://bjsm.bmj.com/content/50/11/669.abstract). > [@](#): > > A total of 777 documented reports of accidents (1230 injuries) were retrieved for the years 2002 and 2012. There was no significant difference between incidence and injury rate between 2002 and 2012. … Severe injuries were seen in 29.5% in 2002 and in 30.1% in 2012. Given that bikes have gotten faster and more fragile (carbon fiber), pelotons larger and more crowded, and that the fields in competitive races are twice the size they used to be (with poor visibility of the road ahead due to so many other racers) I am personally shocked that the rate has not increased, even with helmets. Helmets can only do so much at the speeds these cyclists travel at. Best to avoid cherry-picking studies and go with a solid meta-analysis. [Cochrane](https://www.ncbi.nlm.nih.gov/pubmed/18646128) does 'em best albeit they are often labelled as having an excessively high bar of evidence. As far as helmet legislation effectiveness goes they conclude: > [@](#): > > Bicycle helmet legislation appears to be effective in increasing helmet use and decreasing head injury rates in the populations for which it is implemented Data however of limited quality. And no data if such legislation decreased the number of those cycling and thus increased deaths secondary to decreased fitness. In a typical year 900 deaths occur during cycling. Huge high risk for the typical recreational or commuting cyclist? No. Risk-free also no. I can work in my job with a separated shoulder or a broken collar bone just fine. I need my brain though. I will continue to wear my helmet, my high viz clothing, and use my defensive riding habits. ---
**Author:** ![Turble](https://avatars.discourse-cdn.com/v4/letter/t/8dc957/32.png) [@Turble](https://boards.straightdope.com/u/Turble)\ **Post date:** [December 14, 2016, 4:30pm UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/85 "2016-12-14T16:30:45Z")
> [@DSeid](#): > > Best to avoid cherry-picking studies and go with a solid meta-analysis. [Cochrane](https://www.ncbi.nlm.nih.gov/pubmed/18646128) does 'em best … > . Cochrane does cherry-picking best? It is very widely criticized, one reason being they cherry-picked data, using mostly their own previous studies in their analysis. A couple example with links to many more: [Cochrane review of bicycle helmets: an unsound guide](http://www.bmj.com/rapid-response/2011/10/30/cochrane-review-bicycle-helmets-unsound-guide) [Cochrane Review: Helmets for preventing head and facial injuries in bicyclists](http://www.cyclehelmets.org/1069.html) ---
**Author:** ![snowthx](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowthx/32/10660_2.png) [@snowthx](https://boards.straightdope.com/u/snowthx)\ **Post date:** [December 14, 2016, 10:57pm UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/86 "2016-12-14T22:57:15Z")
To take the tangent from this thread further, I think there is not much disagreement here that mandatory helmet laws are a fools errand. As stated, there are millions, perhaps billions of people who ride a bicycle every day all over the globe without a helmet, and are not any more advantaged or disadvantaged regarding safety than anyone else. However, I think there is a subtle difference that may not have specific data. For example, those millions of people who ride every day without a helmet, perhaps they are using the bike to haul goods or raw materials from/to a small factory, or using a bike to run a quick errand to the corner grocery, or just cruising over to the coffee shop down the street or across a college campus. Let’s say these types of uses are at speeds \<10mph. Then there are your typical North American and European lycra-set, who are using the bike for exercise and fitness, or as transportation to their office job, or are a competitive racer in training, who navigate 1st-world urban and suburban areas while sharing space with other cars and trucks. Let’s say these uses are at speeds \>10mph. My question: the speed of cycling - does that have anything to do with the actual or even perceived benefits of helmets? FWIW: I cannot ride any bicycle, any distance, for any purpose, without putting on a helmet. I feel weird without it. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [December 14, 2016, 11:08pm UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/87 "2016-12-14T23:08:11Z")
> [@snowthx](#): > > My question: the speed of cycling - does that have anything to do with the actual or even perceived benefits of helmets? > > FWIW: I cannot ride any bicycle, any distance, for any purpose, without putting on a helmet. I feel weird without it. Unless you run into a wall, the critical speed is the drop of the head to the ground. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [December 14, 2016, 11:13pm UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/88 "2016-12-14T23:13:06Z")
> [@snowthx](#): > > …FWIW: I cannot ride any bicycle, any distance, for any purpose, without putting on a helmet. I feel weird without it. I think this underscores the plausibility of the risk compensation hypothesis, don’t you? Perhaps “feeling weird without it” might mean that you’d ride extremely cautiously and defensively without the perceived protection of the helmet. ---
**Author:** ![snowthx](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowthx/32/10660_2.png) [@snowthx](https://boards.straightdope.com/u/snowthx)\ **Post date:** [December 14, 2016, 11:25pm UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/89 "2016-12-14T23:25:44Z")
> [@Riemann](#): > > I think this underscores the plausibility of the risk compensation hypothesis, don’t you? Perhaps “feeling weird without it” might mean that you’d ride extremely cautiously and defensively without the perceived protection of the helmet. Yes, similar to seat belts in cars. I am a lot less cautious when I am belted in, so let’s stop wearing seat belts, right? 😉 ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [December 15, 2016, 2:01am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/90 "2016-12-15T02:01:29Z")
> [@Turble](#): > > Cochrane does cherry-picking best? It is very widely criticized, one reason being they cherry-picked data, using mostly their own previous studies in their analysis. > > A couple example with links to many more: > > [Cochrane review of bicycle helmets: an unsound guide](http://www.bmj.com/rapid-response/2011/10/30/cochrane-review-bicycle-helmets-unsound-guide) > > [Cochrane Review: Helmets for preventing head and facial injuries in bicyclists](http://www.cyclehelmets.org/1069.html) It is of note that a even a site like the one you site that is devoted to coming to the conclusion that helmets cause harms has to start off with the admission that > [@](#): > > The Cochrane database has established a reputation as a key resource for medical research. Yes. They do. Having been doing evidence-based medicine for longer than the phrase has been around their reputation is very solid with the criticisms mainly being that sometimes the bar for acceptable evidence is unreasonably high. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [December 15, 2016, 2:04am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/91 "2016-12-15T02:04:41Z")
> [@running\_coach](#): > > Unless you run into a wall, the critical speed is the drop of the head to the ground. If I lose control making a turn on wet pavement and hit the ground when riding at 18 mph I hit the ground harder than if I fall off my bike at a stop. > [@Riemann](#): > > I think this underscores the plausibility of the risk compensation hypothesis, don’t you? Perhaps “feeling weird without it” might mean that you’d ride extremely cautiously and defensively without the perceived protection of the helmet. More likely “feeling weird without it” means the same as my feeling weird if I was walking around outside in my underwear … it’s just not something I do. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [December 15, 2016, 2:12am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/92 "2016-12-15T02:12:15Z")
> [@snowthx](#): > > … My question: the speed of cycling - does that have anything to do with the actual or even perceived benefits of helmets?.. The data on helmets protecting children - who ride at slower speeds - from serious head injuries is great. At racing speeds I am not sure how much good they do. To me the biggest variable is the fact that faster speeds, and road cyclists interacting with drivers, are more likely to have accidents. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [December 15, 2016, 2:15am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/93 "2016-12-15T02:15:35Z")
> [@DSeid](#): > > If I lose control making a turn on wet pavement and hit the ground when riding at 18 mph I hit the ground harder than if I fall off my bike at a stop. Gravity is gravity. Unless something gives you an extra acceleration when you wipe out, your forward speed should not affect how fast you go from upright to ground. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 15, 2016, 2:33am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/94 "2016-12-15T02:33:37Z")
True. Forward speed does however effect how fast your head implants into the side of a tree, a curb, or a car. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [December 15, 2016, 2:41am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/95 "2016-12-15T02:41:45Z")
> [@LSLGuy](#): > > True. > > Forward speed does however effect how fast your head implants into the side of a tree, a curb, or a car. Covered that. > [@running\_coach](#): > > Unless you run into a wall, the critical speed is the drop of the head to the ground. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [December 15, 2016, 3:14am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/96 "2016-12-15T03:14:54Z")
If you are imagining a hypothetical circumstance with a perfectly horizontal surface with no friction then it _may_ be true that the only force at play is gravity. The real world is not that extremely hypothetical circumstance. No it is not true that speed does matter unless is running into a wall. It matters unless you are in an imaginary hypothetical circumstance. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [December 15, 2016, 4:00am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/97 "2016-12-15T04:00:15Z")
[Helmets.org](http://www.helmets.org/limits.htm) > [@](#): > > The typical road or trail bike crash involves a drop to pavement. The important energy in that crash is supplied by gravity, not by forward speed. Although forward speed can contribute some additional energy, the main force is the attraction of gravity, and the impact severity is determined by the height of your head above the pavement when the fall begins. It is gravity that determines how fast your helmet closes with the pavement. Some of the crash energy is often “scrubbed off” by hitting first with other body parts. The typical bicycle crash impact occurs at a force level equating to about 1 meter (3 feet) of drop, or a falling speed of 10 MPH. The rider’s forward speed before the crash may be considerably higher than that, but the speed of the head closing with the ground, plus a component of the forward speed, less any energy “scrubbed off” in other ways, normally average out at about 10 MPH. Unfortunately, there’s no source for their information. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [December 15, 2016, 5:04am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/98 "2016-12-15T05:04:28Z")
Endos are not all that uncommon: drop your front wheel into a deep pothole or fail to miss that possum and you find yourself diving headfirst into whatever is in front of you. In those cases, your forward speed will contribute significantly to the impact of your helmet or head. In the case of losing grip in a turn, that usually means you are leaning into it, which means you are a bit closer to the ground, and the fall vector is mostly across the direction of travel, so speed does not contribute as much to the fall. The problem is that your head is right there up front. Recumbent bikes are better that way because, as the 'bent riders are wont to say, _life is too short to be riding into stuff headfirst_. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 15, 2016, 3:00pm UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/99 "2016-12-15T15:00:38Z")
> [@running\_coach](#): > > [Helmets.org](http://www.helmets.org/limits.htm) > > Unfortunately, there’s no source for their information. Not disputing you, just expanding on your work … Good find. The quote can be summarized as: “Most bike crashes involve falling off onto flat pavement. In those crashes, _and only those crashes_, forward speed is almost entirely immaterial.” Which is completely legit physics. As you and several folks have said. The key point being the quote explicitly makes no claim plus or minus about the nature of crashes involving something other than flat pavement. No claim at all. A casual reader might _assume_ they’re dismissing non-flat crashes as not being a risk. That would be a gross misunderstanding. They’re simply saying non-flat crashes are out of scope for what they want to talk about in that article. Which is a very different thing. I’m not competent to assess the “most crashes are flat” part. For all I know they may be 51% or they may be 95%. Or even only 20% and the quote’s antecedent is flat false. I doubt this latter case, but that’s conjecture, not evidence. The other thing is that if we’re assessing total risk of the activity we ought to weight the crashes by severity. The harm stemming from 99 blisters plus one beheading is different from the harm from 100 skinned knees. Or even 100 broken legs. Yet all three scenarios are 100 bad events. Saying something like “the accident rate is 1 per 10,000 bike miles ridden” sweeps that info under the rug. Sadly many academic research papers and consultant’s position pieces are written based on the stats they can find, not the stats that’d be necessary to truly derive useful real world predictions. Understanding the limits of applicability is difficult and it’s usually \*not \*in the interest of the author(s) to make those limits clear. We need to tease those limits out for ourselves. While avoiding both the reality and the appearance of “cherry-picking”. There’s little doubt that severity is (roughly) inversely exponentially distributed. IOW, lots of blisters per beheading. But I’d bet there’s enough severity out there that an adult riding on urban or suburban roads receives a very real and statistically obvious benefit from a helmet. But we’ll only know if we actually collected the data needed to run the stats. Whether a racer on a track or a child on a playground receives a benefit is a very different question. Which will have a very different answer. But we’ll only know if we actually collected the data needed to run the stats. My overall take, Turble, _et al_, notwithstanding would be that bike helmets reduce the harm of intermediate severity crashes. Both flat pavement and those involving obstacles, even those as minor as curbs. Considering that curbs are within a couple feet of any non-rural bicyclist nearly 100% of their riding time they are a ubiquitous risk factor easily overlooked. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [December 16, 2016, 1:20am UTC](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366/100 "2016-12-16T01:20:44Z")
> [@running\_coach](#): > > [Helmets.org](http://www.helmets.org/limits.htm) > > Unfortunately, there’s no source for their information. Yup. It’s an assertion with no support. Let’s imagine an experiment. You have two identical golf ball sized spheres of modelling clay. Clay ball 1 you drop from three feet onto pavement and it hits the ground at about 10 mph. Clay ball 2 you throw such that it hits the ground with 10 mph force in the vertical axis and 17 mph in the horizontal axis. Both pretty much stop where they made contact. Did those clay balls absorb the same amount of force on impact? Will they be deformed to the same degree? Experiment two. An egg is dropped vertically such that it it hits a horizontal surface of pavement at a velocity that is just below what would break the shell. Quarter of an inch? Whatever. Then it is arranged for it to hit the pavement at the same vertical velocity and with horizontal velocity of 17 mph? Do you believe that it will be at no additional risk of breaking the shell in the latter condition? [Previous page](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366.md?page=4) [Next page](https://boards.straightdope.com/t/does-wearing-a-bicycle-helmet-really-not-effect-the-head/774366.md?page=6)