experiment
We don’t always know why we do things, and often we do stupid things, without ever knowing why. Being the knowledgeable child that I am, I, sadly, quite often know why I do stupid things; mostly I do stupid things out of boredom and curiosity, and stupidity, of course. Anyway,yesterday while writing my note ‘squiggles’, my feet were covering the program bar, meaning I didn’t notice that the few people who were on MSN were talking to me and hence I appeared to ignore them. This offended them, leading them to be grumpy at me, which sucked, so I left. Not wanting to go back to work, and too lazy to do anything useful, I decided to do an experiment I had dreamt up since kayaking on Tuesday. I will open brackets for a brief explanation… (Explanation: I’m doing my 2 star and part of the theory needing to be learnt for this is how to deal with Hypothermia. I knew most of it from PLG, but a few things were revelations to me.) Anyway, all this knowledge I had accumulated about hypothermia was solely theoretical (as, unlike hyperthermia- more commonly known as heat exhaustion- I’d never had to deal with it, or anything even close as far as I knew). As the house was empty and I had nothing better to do (this is a lie- I had plenty of better things to do, I just chose not to do them), I decided to go ahead with my experiment, which I originally called the Cold Bath Experiment. It’s pretty self-explanatory. There was one bath filled with cold water, a stopwatch, a thermometer and a results table already drawn up. Oh, and me. (I did say it was a stupid thing!)
So I took my temperature and jotted it down, then hopped into the bath. It was cold. (This was the first thing that struck me.) While in the bath (for a full 90 minutes) I sang DofE songs, recited my French Oral (because we all know Antonin Artaud is a complete dude and highly appropriate for the bathtub…ew) and shivered quite a bit. I was resolved not to allow my core temp to drop below 36ºC, as 35ºC is the hypothermic onset and I didn’t want to be dealing with that. However, I was pleasantly surprised at the body’s ability to reserve and create heat.
Sitting up to my armpits in cold water, my core temperature went up by over 0.5ºC in the first twenty minutes, and it actually took an hour for my body to drop to the temperature it was before I got into the cold water. I was wholly impressed and decided to stay in for another half hour to see if the rate I was cooling changed. Within 15 minutes I had dropped to the lowest I was prepared to go, but I stayed in out of curiosity and was again surprised to find that I was shivering enough to remain around 36ºC. Having been submerged in cold water for an hour and a half, very bemused, but with teeth chattering so bad I’d had to stop informing the bathroom about other theatre in 1930s Paris, I got out, drained the water and preceded to carefully dry myself and dress. I had assumed that upon being dry and clothed I would warm up pretty quickly, but taking a measurement 10 minutes after getting out I found my core temperature had actually dropped to 35.4ºC. This (and there is no other way of putting it) pissed me off. Why, when I had so artfully managed to maintain heat in the water, did I suddenly lose it when dressed in warm clothes (well trousers and a t-shirt)? Being annoyed I donned my cool black and white cow socks and my PLG hoodie (which is just so damn warm I hate to part from it), and hoped for an improvement in heat. I ate high energy food and made some hot chocolate. For a while heat came slowly, then the sugar kicked in and I warmed up.
So, what lessons did I learn from this stupid thing?
It’s true that shivering keeps you warm. (I had been told in the past that shivering actually increases the amount of heat the body can generate from about 70watts to 400! This meant absolutely NOTHING to me (‘cause I’m bad at physics) but now I see the power of shivering (pun not intended, but shamefully amusing to me (I am very very very bored!))).
Water is a better insulator than air. (I’m not sure about the scientific truth behind this finding- it might be utter crap. If you’re a scientist, help me out.)
But the lesson I’m gonna use most in my day-to-day life is that even when you feel absolutely fucking freezing, chances are you’re ok. I mean, during my time in the water my feet went white, I shivered uncontrollably at times, and I got incredibly sleepy (although that might have been down to Artaud- he isn’t the most interesting guy. I mean, he was great two terms ago but really I could be happier moving on to other things to think about…) BUT I was fine. I didn’t get cold enough for hypothermia to ‘set in’, and really it was just a joke.
Conclusion- that was a stupid experiment and should never be repeated. No benefit will come from it and you’ll just get bloody bored. My only regret is that I didn’t measure my pulse throughout, as it would have been nice to be able to compare pulse rate to increase/decrease in temperature. The human body is awesome. As you will appreciate, I was re-he-he-he-he-he-hearly bored! (I love Dr Cox! Scrubs forever!) Please don’t judge me. I know it was a stupid thing to do (as I said at the beginning) and could have been dangerous, but I had it all under control (and I was really bored!) The moral is- don’t let me get bored. In fact, really, this wouldn’t have happened if I had been sitting like a normal person 3 hours ago and had seen people talking to me on MSN… But (as Akin kindly, noted about me) I hate sitting normally. Now I’m going to do a sensible thing and have some tea- once I’ve told Vodka off for trying to eat my necklace!
Yours as ever,
Titch xxxx (because we’re in a frenchy mood, down here… ‘we’ being me and my hamster… who is, in fact, ignoring me in favour of a cardboard box… why am I still talking!?! Au revoir…)
posted by titch @ 11:03 AM
4 Comments:
This is an awesome post.
Very interesting. I'd not heard that shivering can increase your thermal output so much, that sounds awesome.
I have a couple of comments. Firstly did you remember to make the adjustment for the location that you were taking your temperature from (mouth I assume) and your core body temperature? They're two separate temperatures, although obviously they are related.
As for water being more of an insulator than air. Air is a far better insulator. I'd hazard a couple of guesses as to why you got colder in the air. My first would be that there was lag between where you measured the temperature and your core body temperature, so all your organs etc might well have still been cooling your blood.
Mammals also have some responses to being submerged in cold water head first (heart rate drops and some other things I forget) there might have been similar things going on with your body behaving differently when in water to when it was in air.
There is also the possibility that you didn't dry yourself fully so evaporation of the water was taking heat away from you.
I was also wondering if you'd managed to noticeably heat up the water. So I did a little calculation, assuming you transferred 300W of heat to the water for 90 minutes. Assuming the bath was about 150 litres of water, your body heat will have raised it's temperature by 2.5 degrees (you put in about 1.6 MJ of energy), so that might have had some affect, as the air would probably have been slightly colder (assuming the bath water reached the air temperature after 90 minutes). Might not be significant though.
Maybe the adrenaline had worn off after you felt you were not in danger so your body slowed down a bit.
Incidentally if your body's energy usage really does go up by about 200W then you burnt an extra 250 KCals from this experiment. So not recommendable as a way of losing weight :)
For your information, rectal temperature is the most accurate practical measure of core temperature, so perhaps that is something you ought to consider should you ever repeat the experiment.
In response to the cold, your hypothalamus stimulates shivering in the short-term, vasoconstriction via adrenaline and noradrenaline release in the medium-term, and thermogenesis via thyroid hormones in the long-term. The aim is to increase metabolic rate, in order to warm up the body.
Interestingly, the response is different if you are submerged head first. Fibres of the trigeminal nerve that receive sensation from the face have a more direct connection with the autonomic nervous system, and so actually counteract the hypothalamus to reduce metabolic rate. Their role is primarily to stop breathing so that you don't take in a lungful of cold water, and to slow down the heart so that it requires less oxygen.
Thus, the respose to hypothermia seems to be a fine balance between increasing metabolic rate to warm the body up, and decreasing metabolic rate to reduce nutrient requirements. The former appears to be more important in mild hypothermia when the body is capable of sufficient increases temperature, and the latter in severe hypothermia and when drowning is a risk.
In general, your physiological reserve will be able to compensate by increasing your metabolic rate until you fall below 31 degrees celsius. Below this temperature, the effect of the cold on your enzymes, as well as the trigeminal reflex, causes your metabolic rate to slow right down that your organs just go dormant. Thus, the lack of oxygen to your brain is not a problem in this state. In fact, it is possible to resuscitate people who have been in hypothermic comas for several days. They become undead.
The problem is when the person is warmed up and made undead too quickly. Multi-organ failure usually occurs due to reflex vasodilation causing shock, reperfusion injury, and cell lysis.
Yay for someone with medical knowledge :)
People have been known to survive for 30 minutes underwater while dead but very cold haven't they?
Or is it even longer than that?
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