Friday, January 30, 2015

Seems Like Science: Protect ya neck

I had a revelation recently.

It was a cold evening - so cold, in fact, that it was even a bit chilly in the house. I had thrown on a lightweight shirt with a hood and thumb holes (this one, which I freakin' love), and was feeling pretty comfy in it. For some reason or other, I ended up pulling down the hood, and suddenly I was much less warm.

This got me thinking.

That whole thing about losing more heat through your head than anywhere else? Bunk. So why was I feeling the cold more?

I let it stew in my brain for a couple of days, and was finally hit with the answer as I zipped up the collar of my down vest one night to go for a walk. It may be old news to many of you, but for those who either haven't bothered to think about it or are just as obtuse as I am I'll spell it out for you.

It has almost nothing to do with keeping your head covered - it's all in your neck!

Let's take a look at a diagram of the major blood vessels that run through the area:

Ooh, science-y!

Now think about exactly how much flesh you have keeping those babies insulated, when compared to the rest of your body. Since they're so close to the surface, the blood in those veins and arteries is going to be much more influenced by the air temperature than those in your torso or legs.

The second factor that makes it so crucial to insulate those major blood vessels is their routing and flow. These are no back alleyways - those are huge expressways for transporting blood to and from your brain and heart. If that blood is getting chilled as it runs into your cranium and then again as it comes back into your chest cavity, you might as well be haemorrhaging pure heat!

The same principle applies to your wrists and ankles, as well, though to a lesser extent. While the veins and arteries in those areas are similarly close to the surface, your body's natural defense against cold will slow blood flow to them to preserve heat in order to keep your torso and head warm. Additionally, the blood returning to your torso does have to travel through meatier areas of the body before it reaches your heart, so the impact of the cooling is lessened by the increased distance from your core. Your hands and feet will get cold, of course, and I do recommend wearing gloves with long cuffs (to overlap your shirt or jacket) and good, warm socks that seal off your ankles, but it won't keep you from feeling chilled to the bone if you're still exposing your neck. As a matter of fact, keeping the blood that's flowing into your torso warm will delay the narrowing of the blood vessels that restricts flow to your extremities, so your toes and fingers will thank you for insulating your neck as well!

So what the hell does all this mean, apart from me looking like a dork wearing a hood and thumbies at every opportunity in winter?


I've talked in the past about how essential accessories are for winter running, and I'd specifically mentioned how much use I get out of those multifunctional tubes of fabric that can be headband, earband, balaclava, neck gaiter, or serve other purposes. Icebreaker calls them a chute, Chaos calls them "multi tubular headwear", Outdoor Research calls them an Ubertube and Arcteryx just goes with neck gaiter. There's also that company that doesn't make anything but tubes in various styles and fabrics. While I'd always thought that the best reason for wearing one in winter was to keep my head warm, I generally use them in such a way that they seal between my hat and the collar of my jacket, too - insulating those precious blood vessels that seem to have such influence over my perceived temperature.

Not just while running, either.

Of course, since I've previously discussed my love affair with merino wool, all of the ones I wear are made of this glorious material. They're lightweight, warm when wet, beautifully soft against my skin and dry quickly so they're ready to go for the next day's run or ride. You could do the same thing with a scarf, but the movement of running is likely to cause it to shift, and the trailing ends can be both a nuisance and a hazard.

Even in milder temperatures when I don't require full armageddon proofing, just wearing a top with a zip-up tall collar (like so many quarter- or half-zip running shirts) can make a profound difference in my warmth levels. The beautiful part being that if you start to overheat, you can simply zip down the collar a bit to expose your blood vessel-filled "radiator" to the outside air to cool you down.

As an aside, all of the above is a huge reason why I will never buy a cold weather coat that doesn't have a hood. While it's possible to use a gaiter or scarf to keep your neck warm, drafts can still be an issue: there is simply no substitute for an attached hood and chin-height (or higher) collar that completely seals your neck in an envelope of warmth when the mercury drops past the point when any sane being would go scurrying for the indoors.

So the next time you're heading outside and dreading winter's chill, do yourself a favour and wrap up that neck!

'Cause that's using your head!

Who knew the Wu Tang Clan could teach us about winter running?

No comments:

Post a Comment

Go on, have at me!