Body Heat Loss

Ever heard that "you lose up to three quarters of your body heat through your head, so you'd better put on a hat?" Ever notice, that on your steep alpine approach, that when you take off your hat, you're still bloody hot? I just read an interesting explanation for this "paradox":

http://wildernessmedicinenewsletter.wordpress.com/2007/02/14/heat-loss-through-the-head-and-hypothermia/

This guy took some intrepid volunteers and measured the rate at which they lost heat through various parts of their bodies. They found that there's nothing particularly special about the head; under normal circumstances, you lose about 7% of your body heat through your head. This jives with the "rule of the nines" which says that your head and neck account for about 9% of your total body surface area. The rest of the article is rather unclear, and I leave you to decipher it for yourself; it's hard to tell what people are wearing, how things were measured, etc. Surely, it matters what you're wearing: one can imagine that if you're dressed from neck down in a thick down suit, you're going to be losing more and more body heat through your head, even as the total amount of body heat you lose goes down.

To clarify the situation, I looked around some more. In the British Medical Journal,

http://www.bmj.com/cgi/content/full/337/dec17_2/a2769

Vreeman and Carroll demolish this and many other myths. Apparently, the myth stems from an army study where, as mentioned above, the subjects were wearing survival suits. Well, duh. Indeed, a rigorous study in the Journal of Applied Physiology supports this:

http://jap.physiology.org/cgi/content/abstract/101/2/669?ijKey=8424233366f33e094555aea4283b303397b32ab4&keytype2=tf_ipsecsha

So, there you are. If you forget your hat, your ears may feel cold, but you won't collapse from hypothermia (necessarily).

In completely unrelated news, I've been training my core strength a bit. According to the US Marine Corps and Army PFT standards, I'm quite a wimp. I don't know how I'd do at running (but I'd probably be terrible). I was regularly doing 7 or 8 minute miles over 5 miles for a while, but then my shins started hurting terribly and I switched to stair climbing instead. Despite the surprisingly mediocre athletics facilities at school here, there's a machine which functions like an escalator, except that you walk up it backwards. It feels very much like hiking but it's stairs, not uneven terrain, so the workout isn't quite as good.

Anyways, I should be able to do 3 pullups, 50 crunches or 65 situps, and 58 pushups (various sources). With pullups, I have no problem. I can easily crank out 10, and I don't think it would be too hard for me to get to 15 or even 20. The crunches and pushups are another story, though. I can do about thirty of each at the moment (after doing them for a few weeks), so clearly, core strength is a bit of a weakness for me. But I'm doing them every day or two, so in a few months, I should be "up to spec." I've noticed that when I climb very steep terrain, I do struggle to keep my feet on, particularly for big, semi-dynamic moves. So it'll be good for my climbing, and good for my overall health, too. My shoulders have been clicking oddly and I've had some elbow tendonitis (on the inside), so I've been doing shoulder presses (raise a weight above your head starting with your arm to the side and your elbow pointed towards the ground) and reverse wrist curls (hold a weight with your arm horizontally and your wrist pointed all the way down, and curling it back up to the neutral position). It seems to be helping.

What sort of core workouts do you do? Keller told me he does some sort of ridiculous circuit which "makes people puke." I'm not really into puking, personally, so I'm not aiming for that at all. But he did tell me it involves all sorts of exotica like clapping pushups. That's just overkill, at least for now. I *would* like to be able to do a front lever and one arm pullup, though. I can do a half-lever (hanging from both arms, body horizontal, with one knee tucked in), in so-so form, for about five seconds if I'm hanging from rings. And I can do a one-arm lockoff with my right arm (left is weaker) for about five seconds, although that is pretty stressful on my shoulder. So I'm making progress, but it's going to be quite a while before I have that kind of strength. But that's part of the fun of training right? It's the dizzying highs of success and improvement, followed by the doldrums of injury, regaining old ground, and plain plateaus. Woo hoo!