How to protect your brain by not wearing a helmet

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Steady rider
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How to protect your brain by not wearing a helmet

Postby Steady rider » 6 Jul 2020, 9:09pm

The following is only a very rough estimate to consider how the brain may benefit by not wearing a helmet. The common view would be wearing one must offer a benefit.

Lets start by looking at the level of risk. Roughly 5 serious brain injuries per million hours cycled, according the NZ data. For the UK roughly 300 million hours cycled per year would equate to 1500 brain injuries per year. if 10 million people use bicycles in the UK, that equates to one brain injury per 6000 years cycled or if cycling for 60 years per lifetime, once in 100 lifetimes.

So if a benefit occurs it would be unlikely to be in the average persons life of cycling.

Some research, Williams 1989 and Smith et al 1993, has detailed the impact location on helmets from typical accidents. It showed most were to the sides or temporal area of the head. Impacts to the top or front were less common, helmet testing may therefore be weak. Helmets usually reduce the levels of accelerations in testing but increase the duration of impacts, brain injury often depends on both.

Effects of bicycle helmet wearing on accident and injury rates, GB National Road Safety Conference, November 2019

https://www.researchgate.net/publicatio ... jury_rates
shows the accident rate increase with helmet use.

Robinson 1996 refers to the Wasserman data that detailed the incidence of cyclists hitting their head/helmet during an 18-month period was “significantly higher for helmet wearers (8/40 vs 13/476 - i.e. 20% vs 2.7%, p 0.00001)." A bare head width of approximately 150mm may avoid contact compared to a helmeted head at approximately 200mm wide (Clarke 2007). Assuming the 20% and 2.7% figures are typical, on a yearly average for helmeted and non-helmeted the risk of hitting their helmet or head would be 13.2% and 1.8% respectively. The increased risk of impact for helmeted about seven times higher. A degree of protection could be expected plus a degree of risk from the extra impacts.

Evaluating Cycling Fatality Risk with a Focus on Cycle Helmet Use Dec. 2018 http://worldtransportjournal.com/wp-con ... 4.4opt.pdf raises concerns.

http://nicochevalier.net/wp-content/upl ... iction.pdf
Colloids and Surfaces B: Biointerfaces
926 N.R. Chevalier / Colloids and Surfaces B: Biointerfaces 159 (2017) 924–928 ology willallowforhighthroughputmeasurementsofhair-on-hair friction
nicochevalier.net

The static hair-on-hair friction coefficients I found were in the range 0.12–0.25; they are consistent with static (s) or dynamic (k) values reported in the literature (Schwartz et al. [2], s = 0.16–0.3 for wet hair; Sadaie et al. [10] k = 0.1 c–0.2 in air at 50% relative humidity (RH); Luengo et al. [5] k = 0.05–0.3 in air at 75% RH)


It appears the friction of human hair may be lower than for cycle helmets. Some research appears to be in error considering they are similar.
https://medcraveonline.com/MOJSM/biomec ... njury.html

Real-life accidents are rarely this simple, however, instead typically involving an oblique head impact 3 that produces a rotational torque on the helmet and thus, the head. Indeed, since angular brain acceleration can be more injurious than linear acceleration in impact scenarios,4 a helmet that can dissipate linear impact energy may either not sufficiently reduce, or may even increase, angular accelerations.


Defining the frictional coefficient between the human head and the impact surface required an appraisal of the literature; however, there is a wide range of skin friction values between μ = 0.5 and 1.1 25-27 although none describing interactions of the human scalp or hair,

Figure 8 Peak angular accelerations.
Shows from side impacts (quite a frequent impact zone), a higher peak angular acceleration. The friction coefficient of hair could be lower giving reduced levels of rotational accelerations.

https://bmjopensem.bmj.com/content/6/1/e000746.full
The mean duration of PCS for helmet wearers was 22.9 months, and 16.8 months for patients not wearing a helmet at the time of concussion (p=0.41).

So it appears helmet wearers will incur more impacts and have bicycling-related concussions leading to longer periods - postconcussion syndrome in adults. In addition to more accidents.

So by not wearing a helmet you are more likely to gain a benefit in not having impacts and have a lower risk a concussion or multiple concussions and fewer accidents. This could mean you are protecting your brain by not wearing a helmet.

Some concussion data for the USA compared to cycling levels
http://www.cycle-helmets.com/us_helmets.html

Seems like more concussions compared with prior to widespread helmet use.
https://www.youtube.com/watch?v=NJ-VEZmzSs4

On the other hand some medical reports comparing helmeted to non-wearers find a lower proportion of head injuries for helmeted. They are usually comparing a relatively small sample of total accidents and falls.

Icsunonove
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Re: How to protect your brain by not wearing a helmet

Postby Icsunonove » 9 Jul 2020, 11:10am

The way I've rationalised not wearing one:

UK DfT research report (2009) claimed that between 10% and 16% of fatal injuries might be prevented by the wearing of a helmet. In the UK, according to published figures there are typically 100 to 110 cyclists are killed annually. The total annual distance covered by bicycle in the UK is claimed to be roughly 3.33 billion miles (Cycling UK 2018). i.e. Statistically typically one death per 30.3 million to 33.3 million miles covered. So, with a benefit of 10% to 16% you might expect helmet might save a life once every 189 million to 333 million miles.

Now, I'm currently a relatively high mileage cyclist... If I do 10,000 miles a year, using the DfT estimate I can expect a helmet might save my life once every 18,940 to 33,300 years.... For me, that's a long time to be wearing a helmet.... and a lot of helmets (assuming I replace once every 10 years).

I know that a good proportion of cyclists do wear helmets and that this will distort the figures used and calculated above; and my basic numeracy doesn't extend to taking this into account. However, since the benefit effect of helmet wearing is relatively low (10% to 16%), I don't think it will alter the overall picture too much. (I still would have had to be cycling 10,000 miles a year, every year, since when you could still walk to France (and most of Britain was covered in ice) and many millennia before the Egyptian pyramids were built.)

This does make me wonder about all those "My cycle helmet saved my life" stories.

UpWrong
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Re: How to protect your brain by not wearing a helmet

Postby UpWrong » 14 Jul 2020, 5:55pm

It's a hard one. I fell off a couple of weeks ago and banged the side of my helmet on a kerb. But would it have happened if I wasn't wearing a helmet? - a helmet makes your head bigger.

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Syd
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Re: How to protect your brain by not wearing a helmet

Postby Syd » 14 Jul 2020, 6:32pm

UpWrong wrote:It's a hard one. I fell off a couple of weeks ago and banged the side of my helmet on a kerb. But would it have happened if I wasn't wearing a helmet? - a helmet makes your head bigger.

Unless you have neck muscles of almost superhero strength, that would have allowed you to stop you head moving in that extra cm or two, then it’s virtually certain you’d have hit your head either way.

Jdsk
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Re: How to protect your brain by not wearing a helmet

Postby Jdsk » 14 Jul 2020, 6:41pm

Syd wrote:
UpWrong wrote:It's a hard one. I fell off a couple of weeks ago and banged the side of my helmet on a kerb. But would it have happened if I wasn't wearing a helmet? - a helmet makes your head bigger.

Unless you have neck muscles of almost superhero strength, that would have allowed you to stop you head moving in that extra cm or two, then it’s virtually certain you’d have hit your head either way.

It's that type of injury where I think a helmet might just make the marginal difference to the only brain I'll ever be issued.

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Re: How to protect your brain by not wearing a helmet

Postby Steady rider » 14 Jul 2020, 8:06pm

I fell off some time ago and very nearly hit my head, it took about one to two second to fall, I had time to move my head away from the kerb.
If I had been wearing a standard helmet I would have probably hit it and perhaps cause some ill effects.

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Syd
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How to protect your brain by not wearing a helmet

Postby Syd » 14 Jul 2020, 8:27pm

Steady rider wrote:I fell off some time ago and very nearly hit my head, it took about one to two second to fall, I had time to move my head away from the kerb.
If I had been wearing a standard helmet I would have probably hit it and perhaps cause some ill effects.
A fall tends to bring about instinctive actions so doubt I’d have time to consciously work out where my head is likely to land, and make appropriate adjustments, so yes, on an uneven surface, it is possible a helmet may turn a near miss into contact.

As to the effect on that I couldn’t say and wouldn’t want to put it to the test.

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mjr
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Re: How to protect your brain by not wearing a helmet

Postby mjr » 15 Jul 2020, 11:20am

UpWrong wrote:It's a hard one. I fell off a couple of weeks ago and banged the side of my helmet on a kerb. But would it have happened if I wasn't wearing a helmet? - a helmet makes your head bigger.

Was it a helmet where the side is tested and shown to be protective? Most of them only test the top, a zone above 5cm above the equator of the headform IIRC. Even MIPS only tests six points broadly inside that zone, not the sides. The sides are mainly to prevent the helmet sliding around during the crash.
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pjclinch
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Re: How to protect your brain by not wearing a helmet

Postby pjclinch » 15 Jul 2020, 11:35am

Jdsk wrote:
Syd wrote:
UpWrong wrote:It's a hard one. I fell off a couple of weeks ago and banged the side of my helmet on a kerb. But would it have happened if I wasn't wearing a helmet? - a helmet makes your head bigger.

Unless you have neck muscles of almost superhero strength, that would have allowed you to stop you head moving in that extra cm or two, then it’s virtually certain you’d have hit your head either way.

It's that type of injury where I think a helmet might just make the marginal difference to the only brain I'll ever be issued.


It's fun to see the cycle training community (of which I am a member, but of the enfant terrible tendency at times) do their risk assessments for Bikeability 1 or Play Together on Pedals in a school playground. Risk, children may fall, Control, all participants to wear helmets. Splendid!

After the lesson the kids go back in, and emerge sometime later for their free play in the lunch hour or break, during which time as an almost daily occurrence one or more will fall over and hit their head, there will be floods of tears, their pal will escort them to the office and they'll get some TLC, an "I've Been Brave!" sticker, and because it's a head injury they'll also get a form letter home saying they hit their head and an extra "I banged my head :( " sticker. Nobody atthe school notices that the extra controls for the Bikeability (much greater supervision ratios, readier access to first aid, planned activity and site-specific RAs to keep bikes away from troublesome stuff like playground furniture) already make it safer than playground free play, yet it still engenders the Risk management Measure Of Last Resort, PPE.

The fear of a brain injury is part of current UK cycling "culture". It's important because people go on about it rather than it happens a lot, so people are hyper aware of it. So we have instances where they'll drive to a cycle event but not use their helmet in the car (why wouldn't you, if it was only about "just in case" risks to your only brain?), or ride to something like an ice rink and totter about on sheets of ice surrounded by uncontrolled skaters of wildly varying ability for an hour with far less worry about hitting their head than on their bike.

Why don't those marginal possibilities matter there? Because the culture is different, and the culture overrides the risk. The ground is just as hard in NL, gravity much the same, segregated fietspads don't stop you falling off, and yet it's not a worry there. That's not because it isn't a risk, but that the culture says it's not a significant risk worth the faff.

This is not saying to folk they should stop wearing a lid to ride if they don't use one to drive, skate etc., but it's useful to realise that it's a rationalisation rather than a cold, hard, objective risk assessment. We all rationalise stuff, it's a basic human thing, but I think it's good if we can say "I just prefer doing it this way" to imagining particular scenarios that justify our gut feelings. One of the things I like about Tim Gill's consultancy piece with the helmet annex is he's honest enough to admit he wears a helmet for personal "what if?" feelings despite his evidence-led conclusions that the case for recommending them at a policy level has not been properly made.

Pete.
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reohn2
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Re: How to protect your brain by not wearing a helmet

Postby reohn2 » 15 Jul 2020, 12:18pm

^^^ THIS
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I cycle therefore I am.

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NATURAL ANKLING
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Re: How to protect your brain by not wearing a helmet

Postby NATURAL ANKLING » 15 Jul 2020, 12:29pm

Hi,
UpWrong wrote:It's a hard one. I fell off a couple of weeks ago and banged the side of my helmet on a kerb. But would it have happened if I wasn't wearing a helmet? - a helmet makes your head bigger.

I fell off on black ice and hit the side of my head on a relatively solid ground.
I reckon I suffered mild concussion for several days.
This is the first time in 52 years riding.
The helmet was damaged, the argument goes that if I was not wearing a helmet my head wouldn't have come anywhere near the ground.

These sort of things are for once-in-a-lifetime experience not your every day one.
You pays your money and takes your choice.
Incidentally I landed on my hip too after a few minutes I struggled to stand and was a real challenge to get home using just one leg powering. Several x-rays and couldn't walk for several weeks without crutches.
Without the helmet I probably would've needed and ambulance, this is just my opinion, my head collision Was not recorded anywhere, how many are actually recorded when someone damages their helmet?
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De Sisti
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Re: How to protect your brain by not wearing a helmet

Postby De Sisti » 17 Jul 2020, 7:41am

UpWrong wrote:It's a hard one. I fell off a couple of weeks ago and banged the side of my helmet on a kerb. But would it have happened if I wasn't wearing a helmet? - a helmet makes your head bigger.

You should have put your hands down to break your fall (even babies do that when they lose their balance
trying to walk)
and wore protection for your palms to prevent them from being damaged.

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pjclinch
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Re: How to protect your brain by not wearing a helmet

Postby pjclinch » 17 Jul 2020, 8:18am

De Sisti wrote:
UpWrong wrote:It's a hard one. I fell off a couple of weeks ago and banged the side of my helmet on a kerb. But would it have happened if I wasn't wearing a helmet? - a helmet makes your head bigger.

You should have put your hands down to break your fall (even babies do that when they lose their balance
trying to walk)
and wore protection for your palms to prevent them from being damaged.


Babies do that because it's a reflex action. Same reflex action happens falling off a bike, right after the reflex action to try and stay up, but sometimes it's just not quick enough. The point about reflex action is it doesn't involve any conscious thought, so "you should have..." is a non-sequitur.

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profpointy
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Re: How to protect your brain by not wearing a helmet

Postby profpointy » 17 Jul 2020, 8:59am

Steady rider wrote:I fell off some time ago and very nearly hit my head, it took about one to two second to fall, I had time to move my head away from the kerb.
If I had been wearing a standard helmet I would have probably hit it and perhaps cause some ill effects.


Ah but then you could say "the helmet saved my life"

Joking aside I once somersaulted over a car which had pulled out then stopped, landing on my shoulder. Apart from being winded and the gradual appearance of a bruise covering 3/4 of my chest I got away with it, but seeing the impact point on my shoulder made me realise my head can only have missed the ground by the width of a helmet. I could easily have got concussion and / or a neck injury and been convinced by helmet wearing had I been wearing one.

Of course, this isn't "evidence" one way or the other, but does indicate why the "it's obvious" argument for helmet wearing could easily be false - as indicated by the Australian experience

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Re: How to protect your brain by not wearing a helmet

Postby PaulaT » 17 Jul 2020, 9:07am

Icsunonove wrote:This does make me wonder about all those "My cycle helmet saved my life" stories.


No different from the "my lucky rabbit foot saved my life" or "my St Christopher cross saved my life". Just anti-science bias confirmation.