Bicycle helmets do almost nothing to prevent concussions • Hacker News Board

Re: Bicycle helmets do almost nothing to prevent concussions

#51

Post by robg » Sat, Oct 11, 2014, 11:34 AM UTC

Consider that your brain is an egg yolk floating in a shell. A concussion is the rapid loss of velocity slamming the yolk into the inside of the shell, scrambling it up if you will. A helmet can't do much there except minimize the velocity a tad bit.

The benefit of the helmet is prevent a crack in the shell, your skull, so your brains don't spill out onto the pavement in a crash. It's not perfect, but given your are traveling at high rates of speed on a hard surface, the insurance is your brain mostly intact inside the shell versus a scrambled mess on the ground.

Preventing concussions - the yolk from slamming into the inside of the shell - is a hard problem. The brain is floating in liquid - the cerebrospinal fluid. To take another example, drop a ping pong ball into a glass of water. Now try to move fast without the ball hitting the side of the glass. The amount of padding on the outside of the glass won't do much to prevent the ball from hitting the inside of the glass.

It's not just crashes you need to worry about. Even roller coasters cause concussions, albeit small ones, but still with cognitive decrements.

Re: Bicycle helmets do almost nothing to prevent concussions

#52

Post by brational » Sat, Oct 11, 2014, 11:42 AM UTC

robg wrote: post #51

Consider that your brain is an egg yolk floating in a shell. A concussion is the rapid loss of velocity slamming the yolk into the inside of the shell, scrambling it up if you will. A helmet can't do much there except minimize the velocity a tad bit. The benefit of the helmet is prevent a crack in the shell, your skull, so your brains don't spill out onto the pavement in a crash. It's not perfect, but given your are…

Yep. Its worth noting that (american) football helmets are the same. They dont provide shake protection just prevent skull fractures.

Re: Bicycle helmets do almost nothing to prevent concussions

#53

Post by witoldc » Sat, Oct 11, 2014, 11:44 AM UTC

Some of this debate is also going on in the motorcycle industry. "Softer" helmets provide better outcomes in slower crashes. "Harder" helmets provide better outcomes in faster, harder crashes. (To some extent, this is "DOT" approved helmets vs "SNELL" approved helmets.)

You can't really have both unless you make the helmet bigger, or use some more exotic and more expensive materials. Fact of the matter is that EPS is cheap and works really, really well. It's what helps you SURVIVE - not save you from a silly concussion. (silly, comparatively speaking.) That is the fundamental functionality of a helmet. Maybe someone will make a $1000 helmet that is slightly better in avoiding concussions in smaller accidents, but people do not think there is much market for such a product.

I couldn't muster to keep reading after the writer deemed 1-127 degrees F as "extreme conditions." 127F is what your helmet bakes in when you leave it in the car, for example, and there are plenty of regions around the world and US where it is easy to hit 127F by leaving the helmet in the wrong place. It's hardly "extreme."

Re: Bicycle helmets do almost nothing to prevent concussions

#54

Post by damian2000 » Sat, Oct 11, 2014, 11:46 AM UTC

Being from Australia I can't fathom not wearing a helmet. Its like wearing a seat belt in the car, just something you don't notice doing anymore.

Anyone who is discouraged from cycling due to having to wear a helmet would more than likely also be discouraged by many other reasons - bad drivers, bad weather, flat tire, etc.

Re: Bicycle helmets do almost nothing to prevent concussions

#55

Post by nl » Sat, Oct 11, 2014, 11:50 AM UTC

revelation wrote: post #48

nl wrote: post #32

Earlier quoted context omitted.

Regarding the reduction is cycling: the share of cycling as a transport mechanism fell by almost the same amount in a number of jurisdictions with no mandatory helmet laws over the same time period[1]. People in the transport strategy field generally seem to think the cause of this change was more dual-car families. However, I used to be strongly in favour of mandatory helmet laws. Now I tend to think they need to be…

The idea being that a) cyclists should fuck off, b) pedestrians deserve no space or protection and c) the burden of mitigating danger needs to be placed on those most vulnerable to it, not those introducing it in the first place (cars). This is thinking from the 1950s. All of these things have failed dramatically.

I'm unsure if your response is to my ideas around helmet laws or something else? For context, I'm from Australia, where helmets are mandatory for all bike riders. Making them non-mandatory is a change that some think will increase cycling uptake.

Anyway, if it was to me, then

a) I'm a cyclist (over 6000km and 115,000 vertical meters this year. That's further than I drove).

b) Of course pedestrians deserve space. I'd prefer to change the laws to allow non-helmeted riding on separated bike paths only, but that would be useless as where I live most separated bike paths don't link up which means people must either ride on the road or (illegally) on the footpath to get between them. In a world where not everywhere is Copenhagen or Amsterdam I'd prefer to see children ride to school with their parents on footpaths than not ride. I'd prefer to see people who worry about helmet hair ride to work on footpaths and separated bike paths than not ride. Where I live both these things are currently illegal.

c) Yes. Riding on roads needs to be made safe. That does not preclude encouraging more diverse transport choices by making other changes too.

I find too many cycling advocates come from entrenched pro or anti-helmet positions and aren't prepared to look for compromises. That isn't helpful overall.

Re: Bicycle helmets do almost nothing to prevent concussions

#56

Post by 3pt14159 » Sat, Oct 11, 2014, 11:55 AM UTC

damian2000 wrote: post #54

Being from Australia I can't fathom not wearing a helmet. Its like wearing a seat belt in the car, just something you don't notice doing anymore. Anyone who is discouraged from cycling due to having to wear a helmet would more than likely also be discouraged by many other reasons - bad drivers, bad weather, flat tire, etc.

I don't wear a helmet and I ride in downtown Toronto. Helmets save lives, but they also make motorist treat you differently. Also, they don't really save that many lives. Cycling without a helmet is safer than walking (kilometer for kilometer) and safer than being in the passenger seat while a new driver is driving.

Re: Bicycle helmets do almost nothing to prevent concussions

#57

Post by sklogic » Sat, Oct 11, 2014, 11:56 AM UTC

dmpk2k wrote: post #36

sklogic wrote: post #25

Besides being useless, there are also some negative side-effects: helmet limits field of vision significantly and distracts from perceiving audio- and visual- information properly. I feel blindfolded in a helmet, even in a very light one.

This is about bicycle helmets, not motorbike.

Yes, and I'm talking about the bicycle helmets. The only crash I had in my 25+ years of cycling was when I had a helmet - for the first time.

Re: Bicycle helmets do almost nothing to prevent concussions

#58

Post by pessimizer » Sat, Oct 11, 2014, 12:05 PM UTC

Tomte wrote: post #37

awjr wrote: post #31

As a space for cycling campaigner ( http://www.cyclebath.org.uk ) helmet articles are an interesting problem that tend to identify cycling as a dangerous activity without extolling the health benefits of cycling itself. In places like New York, where their Citi Bike scheme has had huge success without helmets (23 million miles of riding, no deaths), utility cycling (commuting) has been made safe through a huge invest…

> The point is, helmets and cycling create flame wars The point is, you are very much involved in creating flame wars by labelling the pro side as people who only have their superstitial, anecdotal fairy tales, while saying the contra side has all the cold, hard scientific facts. Let's just leave it at that.

It's just an observation of fact. Facts are known to be biased. If there are studies that show the benefits of bicycle helmet wearing, I'd be interested in seeing them.

Re: Bicycle helmets do almost nothing to prevent concussions

#59

Post by merraksh » Sat, Oct 11, 2014, 12:05 PM UTC

Snively estimated that a naked head struck the surface with a force more than 1,000 times greater than gravity, or 1,000g, which is lethal.

I assume it meant "the acceleration of a naked head upon hitting the surface is estimated as 1000g", as I can't make sense of it otherwise. It would also help to say what height he dropped it from or the impact speed.

Re: Bicycle helmets do almost nothing to prevent concussions

#60

Post by TheAnimus » Sat, Oct 11, 2014, 12:17 PM UTC

Tomte wrote: post #37

awjr wrote: post #31

As a space for cycling campaigner ( http://www.cyclebath.org.uk ) helmet articles are an interesting problem that tend to identify cycling as a dangerous activity without extolling the health benefits of cycling itself. In places like New York, where their Citi Bike scheme has had huge success without helmets (23 million miles of riding, no deaths), utility cycling (commuting) has been made safe through a huge invest…

> The point is, helmets and cycling create flame wars The point is, you are very much involved in creating flame wars by labelling the pro side as people who only have their superstitial, anecdotal fairy tales, while saying the contra side has all the cold, hard scientific facts. Let's just leave it at that.

There is also another benefit of a helmet, it changes how people treat you. They apparently respect cyclists more when they wear a helmet.

I was in a collision a two months ago. The driver hit me on purpose, because I had call him a wanker, he became self defining in this, by swiping me with the rear of his car, thankfully the relative speed difference would have been at most 10mph, so I only had minor injury (three fractures).

The police, who have a job to collect evidence, were not remotely accepting that I was not doing anything wrong. My arm was injured, my head obviously not, so before the ambulance arrived someone had helped me remove it, and clip it to the holder on my bag. Immediately the police were questioning me, asking why I wasn't wearing my helmet when the accident happened.

My head never came close to hitting the ground during the impact.

The fact is that people are very judgemental. Cyclists who wear helmets tend not to be the ones who cycle straight through junctions at red lights whilst smoking a spliff such as the space cadet I saw this Monday the 6th, 9:30am, Highgate.

It was interesting, that despite the obvious location of the collision, A lane that the car should not have been in, the Police were been told off by the paramedics for been hard on me, taking me off gas+air (mild anesthetic) so I could be breathalised for signs of alcohol consumption would be one good example of how I feal they acted poorly. Only after they found my pilots license did the police start to treat me with any dignity or respect, it was frankly shameful, as the other party had already admitted he used his car to injure me to a witness. Best of all, the driver isn't even been charged with assault.