Your friggin brain is still working well, that’s good news!

The visor deals with branches before they smack you in the mask/eyes.

Most mountain bike helmets have greater rear coverage. Also variants with removable full-face components, etc.

Bicycle helmets are one-and-done, in that if you take one major hit with them they are meant to be discarded, it’s why they don’t really cover the side of your head, Ski helmets like Skate helmets cover your sides because they’re meant to take multiple hits.

Thoughts on MOUNTAIN biking helmets versus ski helmets? Both sports see high speeds and crashes into trees.

With kids it’s almost always about look. Helmet with a Mohawk is better than fighting the kids for an hour to wear an aero roadbike helmet. Both protect their heads.

> Skiing typically involves higher speeds than cycling

Really? I would not have thought that. Coming from a mountain and road biker who very often bikes above 20 mph, but very often bikes much slower than that as well. That said, most of us don't wear helmets on the way UP the mountain. In montana the way up is basically just up for a couple hours till you reach the top. You're going, at max, a few MPH and the worst thing you'll do is fall off (while stopped) and hit your head on a rock, which is easily enough avoided.

Down though, yeah, most of us wore full faced helmets (which was another reason why we didn't wear them on the way up. Wayyy too hot.)

I had a convertible helmet that had a strap on lower half so I could wear the upper half while climbing and I'd strap on the lower half for descending. It was nice. Not cheap, but nice.

There are a few possible explanations.

One is that the animals may just be better at preventing or dealing with cancer. We know the, for example, part of the hardiness of tardigrades comes from special proteins that are really good at repairing DNA. It could be that large animals have similar tools that we haven't identified yet.

An odd possibility is "supercancer". Cancer is deadly because as tumors grow they suck up vital resources from functional tissues and organs, and physically get in the way of the organs. What if a tumor had its own cancer? The secondary tumor would suck up resources and choke out the primary cancer, just like cancer normally does to healthy tissue and organs.

Because the animals are so big, tumors can grow for longer and get bigger than they could in smaller animals like humans. That gives more opportunities for supercancers to develop inside those tumors.

>Buying a new helmet is much, much cheaper then treating a head injury.

This was a convincing argument for me to stop acting dumb about safety. I crashed while using a brand new helmet and was put out about having to shell out over $100 in the same season. I had to be reminded that it's expensive because it protects my friggin brain!

That really is a style thing. I'm guilty of it. Road is aero. Dirt gets a visor. The visor does almost nothing but you look pretty silly without one.

Good point! Any helmet that takes a hit, or even gets dropped hard, should be carefully inspected to make sure the shell is intact and the interior materials aren't compromised. Buying a new helmet is much, much cheaper then treating a head injury.

Helmet design for motorcycles vs driving cars (e.g. racing) also differ this way based on type of impact. Car helmets are more resistant to crushing force impact. Motorcycles and bikes are designed for repeated, low crush force impact, as would happen when your body is thrown from the bike and head is skipping across the pavement.

Some of the evidence is glorious- Dr Ian Walker, serious scientist and researcher, wearing a wig and riding along while intentionally wobbling.

The fun part is when you throw in the impact of NOT cycling- ie, people being deterred from exercising, because they think it's dangerous, or the helmet is too expensive, or because it looks stupid. Australia's helmet mandate laws almost certainly caused more negative health impacts than positive, partly because people exercise less and partly because the reduced number of cyclists make it more dangerous for the remaining cyclists.

I totally believe there are net safety benefits to wearing a helmet, personally. But I also totally believe that they're pretty trivial statistically. Serious head injuries are relatively uncommon and, as a complicating factor in road accidents, often come along with other injuries. Minor head injuries are also worth protecting against though!

Ski/Snowboard helmets are also supposed to be tossed after one hit. There are helmets with special material that allow multiple hits, which is manufactured for both bikes and snow sports, but it's not interent to ski helmets.

Second that. Always get the urge to roll my eyes a little when parents buy kids skateboard helmets for use on a bike because they "look cooler".

It's 100% better than no helmet but it is not designed for optional protection in most bike accident patterns

I've seen all manner of arguments against using helmets which have nothing to do with injuries among "crash involved cyclists".

In a typical year I like to bike about 5,000 miles. Cars have close-passed me, tried to run me off the road, cut me off, yelled, spit, cursed, you name it. I've had drivers mad at me for going the speed limit, not going the speed limit, being in a bike lane, being within 3' of the curb, pretty much all of it. I used to have a bus driver who hated to let me ever get around him because once I got in front of him I'd slowly gain distance because he had to stop to pick up and let off people.

What I care about is what happens if or when my head hits something.

And then mountain biking also has different helmets.

In addition to the reasons mentioned already, ski helmets are designed to take multiple hits, but you toss a bike helmet after it takes one.

Right, but even if we we're to accept those results at face value*; they don't necessary contradict what I said. The study is "among crash involved cyclists". There's evidence that motorists drive closer to cyclists wearing helmets, so it wouldn't be a stretch to imagine that wearing a helmet increases the risk of being involved in a crash in the first place.

If you're looking for the risk of KSI with or without helmets; then that's the thing you need look at amongst all cyclists... not restricting it to the population of "crash involved cyclists".

​

* which I don't necessarily - for some papers at least you can show that using the methodology in the paper it follows that wearing a helmet reduces the risk of leg injuries...

I've not seen the data in years, but it is out there.

Bicycle helmets - To wear or not to wear? A meta-analyses of the effects of bicycle helmets on injuries

This article points out that cervical spine injuries aren't reduced, and as many bicyclists will tell you, there are plenty of other bones left to break. However, when it comes to protecting your skull, a bicycle helmet will do that better than no helmet.

Apart from injury mitigation considerations; when you're skiing getting cold is often a concern; whereas for cycling you're normally too hot.

Skiing typically involves higher speeds than cycling, so ski helmets tend to be stronger. Cycle helmets are not designed for high speed impacts, rather to mitigate the kind of thing that you might expect when fall off your bike - i.e. the speed your head picks up as you drop vertically off a bike.

Incidentally - as far as I know there's no good quality evidence that the wearing of cycle helmets actually makes any statistical difference to the likelihood of death or serious injury.

I hadn't considered the heat, but was going to say the second part.

Different helmets for different falls.

BMX / skateboard helmets are also very different from road-bike helmets.

They wear different types of helmets because the risk of injury to the skull comes from different types of injuries.

Bicycle sheets are designed to protect a rider from impact with the pavement and motor vehicles. These injuries often occur from side and top impact to the head.

Skiing injuries are usually from impacts with trees. These injuries occur from impact while forward facing.

American football helmets are another type of helmet with different priorities.

Bicycle and skiing helmets also prioritize hearing differently. Bicycling safety requires hearing skiing doesn't.

Dumb reason # 1- bike helmets don't keep your head and ears warm. Ski helmets should not be worn with a hat, so they have built in "hat" materials to keep your head warm. Biking helmets are usually designed with the opposite intent, to provide airflow and keep your head cool.

More Sciencey Reason - If you look at how a person falls and their head hits things on a bike vs. sking you'll see different patterns. Bonking your noggin' doesn't equal bonking your noggin in all cases. Specifically, snow sports usually involve sideways hits and biking involves front on hits. So the whole design is slightly different.

The short answer to your question is we simply don't know, and this is an area of ongoing research. We should expect to see cancer far more frequently in larger animals, just given the larger number of cells and the larger chance of accruing oncological mutations. Surprisingly, this is not what we see when we look at animals such as elephants and whales, and we really don't know why