The heat was torrid. We were invited to Boguty (mountains to the east of Almaty) for a mountain hunt and I set out there with my friend and a local guide. The level of our training and equipment was far from perfect, but it was more than compensated by youth and abundance of game. We could finish the hunt on the first day, but we did not manage to hit from 200 m. We travelled along the ridges a bit and made another attempt, this time scoring miss from 150 m. Later we discovered that our SKS scope was defocused. At about 6 p.m. we were quite far from the camp. We had neither water, nor food with us– we did not expect the hunt would take so long. Moreover, I had no headdress. Bathed in sweat and burnt by sun we finally met another group of “teks” (Mid-Asian Ibexes) and were lucky enough to take one of these right on the spot while the second one was wounded (of course this was mine) and ran down the gorge. It is well known that the hunting process induces secretion of loading dose of adrenalin, so I was overwhelmed with it and rushed after the wounded ibex. Besides, this was my first tek ever!
Guys left to skin the animal while I was led further and further down the gorge by blood trail. During the search the fatigue appeared, soon the dehydration added itself to the situation (who’s been to Boguty mountains, knows about the considerable water shortage there). Finally, I found the animal and this fact inspired me greatly. I had no knife, so I shouldered it like the Samson. The ibex wasn’t that big, but I managed to do no more than 200 m up. Then, I began to lose consciousness, started seeing ring-like hallucinations, the nose bled…
The darkness almost fell when I scrambled out of the ill-starred gorge. I read in the eyes of my friends that I looked everything else but normal – it was a mess of ibex blood and faeces mixed with my own nose blood spread all over my face and body. However, I didn’t give a damn about that at the moment – I was reeling and feeling nausea. I don’t remember getting to the car. I remember that I kept thinking about a bottle of beer under the seat and how greedily I would gulp it…
This is how I experienced a thermal shock induced by heat, dehydration, physical activity, emotional outbursts and my own stupidity.
Mechanisms of thermoregulation in humans
Let’s start from the basics. The temperature of internal organs of a healthy man is a bit less than 37 degrees centigrade. The fluctuations limits are 35-42 degrees. If the temperature falls below 35 degrees we feel badly but the organism is still able to working (under certain circumstances). If temperature is above42 degrees centigrade, the blood proteins coagulate and the organism dies.
Apparently, such a temperature sensitive organism should have an orderly system of “sensors”, analyzers and means of struggle for surviving. And, of course, we have them. In our everyday life we encounter with the elements of this system –nerve endings in our skin and a tongue constantly send the signals about temperature changing in the surrounding world. These are so called peripheral receptors. But it is also apparent that human body inner temperature is much more important than the surrounding one. At the end of 18th century the scientists discovered that the central thermo sensor was located in hypothalamus. One brave physiologist let to implant the real thermo sensor into his own brain to prove that brain receptors were more important than those in human skin. In order to lower the temperature inside but not outside the body he had to consume almost 10 kg of ice cream. The following reaction proved the crucial role of hypothalamus receptors.
But let’s return to the periphery. Skin receptors can be divided into two groups – sensitive to warmth from 36 degrees centigrade and higher, and those sensitive to outer temperature decreases (from 35 to 13 degrees). These sensors determine the organism local reaction. If you wash your hands in a mountain stream they’ll turn red. The reason for this is that blood will flow to upper layers of your skin to neutralize the effect of cold water, but the internal temperature of your body won’t change. On the other side, despite the fact that a human with the inner temperature of 42 degrees will surely die, we can comfortably spent some pleasant time in sauna, where the temperature can reach more than a hundred degrees centigrade (the temperature when raw eggs at the same time cook hard boiled). We are saved from the overheating by the perspiration, when the surface of our skin as well as the whole organism is cooled. For the same reason, ascending the certain eminence we bathe in sweat and as a result of chemical reactions under such load our organism emits to 5 times more heat than usual. That’s why mountain hunters should use outerwear provided with additional ventilation abilities, made of quick-drying materials (some synthetic fabrics get dry 20 times faster than natural ones) with good ratio of moisture drainage because right after the overheating you may face freezing-cold wind squall and wet clothes may cause hypothermia (overcooling).
Perspiration is not the only way our organism fights overheating. It also involved electromagnetic radiation (at low rates), thermal conduction – the process of energy (heat) transfer from one object to another (given that these are in direct contact), forced convection – the transfer of heat in mobile medium, for example in wind or water flow (thermal layer around your body can’t be formed in mobile mediums and heat loss goes quickly).
However, the role of perspiration is crucial. It is driven by hormone adrenalin secreted when a body temperature rises or our organism is under the stress (that’s why your hands and forehead sweat when you’re scared). The perspiration can increase the heat loss up to 20 times! On a very hot day a person can lose 10-12 liters of liquid, especially under the forced convection – just remember the feeling of ease when you’re blown with a light cool wind. Therefore, don’t be shy to take off the outerwear during ascending – let the convection increase the thermoregulation process. If the day is hot and windless pour yourself with water – it will help. The water will evaporate from the surface of your body making it cooler.
Otherwise, the sun, physical load, dehydration and absence of cooling may lead to thermal shock with a 30% probability to end up with a lethal outcome. The best anti-shock treatment in the field conditions is a rub-down with warm water (cold water constricts blood vessels and makes the situation worse).
Acclimatization of our perspiration to the heat takes about a week at the same time with sweat desalination (you have to renew the salt balance constantly).
During the intensive physical exercises we lose more water than we are able to drink, that’s why you have to drink as much as possible even if you don’t want it. Generally, having sufficient amount of salts and water our organism is quite able to cope with heat and mountains.
Cold
Our hunting season is to be in autumn and winter. At this time in the highlands one thing is on the watch for us – it is cold. With its strong claws it penetrates under our clothes and locks our movements and minds. Air temperature falls circa 1 degree with every hundred meters above sea level. It is simple to calculate, that having 10 C degrees below zero on a plain, we’ll get 30 C degrees at 3 km elevation! It is rather tolerable temperature if you have warm clothes and high-calorie meals and there’s no forced convection provided by strong wind. Paul Siple, a famous American explorer of Antarctica, had experimentally established the correlation between the wind strength and heat transfer (now we call it wind chill factor). Thus, 29 C below zero with the wind velocity 4-5 m/s feels like 44 C below zero, and with the wind 6-7 m/s feels like 66 C below zero and that is going to be enough for a naked skin to get frostbite in 30 seconds.
If your organism gets cold, it would firstly sacrifice its limbs –hands and feet, because these lose the most of the body heat (due to the large surface area and very dense capillary network).
There is another danger – a possibility to freeze to your beloved rifle with your naked hands. It happens because of thin layer of moisture on skin of your hands. In such cases servicemen recommend simply to urinate on that. By the way, cold and frost increase urine production – blood vessels constrict and the excess liquid is excreted.
What a stress for the organism is all that mountain hunt! First prus uphill, sweat, lose liquids, overheat yourself, then you sit, freeze and lose your liquids again…
Until the body temperature is higher than 35-34 degrees, the organism tries to resist the temperature fall of skin coverings. Firstly, the vessels constrict but when the temperature of the skin falls to 10 degrees they dilate again. In this case you feel severe pain (It is said that it is due to slow removal of metabolic products) and the skins turns from pale to bright red.
Sometimes the process of vasodilation can be activated by physical activity of frozen limbs (remember the episode in Ryazanov film when the character was hopped around a Christmas tree repeating “Drink less”), emotional burst (induced by adrenalin) or by extreme actions like rubbing (medics don’t recommend to do it with snow but with a woolen cloth).
Hearing about “cold” I often remember myself being at an altitude of 3000 m in winter, wearing rubber boots and wet socks. When the sun went down the temperature fell lower than -20 C below zero. My feet began to freeze. Finally, I understood that I needed to do something otherwise I would get frostbite. Luckily, I had an extra pair of woolen socks. I took off the boots. My feet “looked miserable” and absolutely lost the sensitivity. I wrung insoles, thoroughly rubbed my feet with a sweater and they returned to life in dry socks. But how painful it was! With each step it felt like you step on thousands of needles.
When our body experiences considerable exposure to cold it tries to war itself up in the most familiar manner – by involuntary contractions of muscle tissues referred to as shivering. However, despite all mechanisms of self-defense, the cases of hypothermia in the mountains aren’t that rare. Among the most distressing things is a loss of sensitivity and muscle activity of hands, when a simple action like lighting a match turns into a challenge. So, before going hunting, prepare a fire in a base camp, who knows, maybe it will save your life. A year ago there was an accident on mt Khan Tengri, when a Polish mountaineer froze to death because he lost the plastic cover of his boot when lost sensitivity of his hands.
There are several other symptoms of hypothermia: weakness, apathy, sleepiness. When the body temperature falls to 32 C the shivering stops, the energy runs out. At 30 C you lose consciousness. When the body cools down to 20 C, the heart stops beating. But most often we don’t follow this sad scenario – frostbites are much more common (mostly of limbs and face). This happens due to overall hypothermia, when tissues temperature falls lower than 0 C – ice crystals form inside cells, cell membranes break and tissues die off.
Frostbites should be treated in hospital. The procedure is very painful and having consequences. After having some minor frostbite of my fingers in my young years (was having a climbing test held by pioneer organization) I still have troubles – when an air temperature slightly falls my fingers lose sensitivity.
Fords and river crossing during the cold season are even more dangerous. Water of the mountain stream will cool down your body 25 faster than air. That’s why crossing the river on foot without safety equipment is very risky. With wet clothes on, your body will cool down 20 times faster than in dry clothes. So do always have an extra set of clothes and thermal underwear.
In the conclusion – all the information in concise form:
- Physical activity during the mountain hunt in a hot weather may lead to thermal shock. To prevent it, use light air-breathing clothes, remember to wear a headdress, drink lots of water, don’t feel shy to take off some clothes for a better convection. If it’s possible, rub yourself with wet cloth – this will speed up the cooling process.
- During the perspiration you lose not just water but lots of salts (up to three tea spoons of salt during one hot day!). Take care of the mineral balance of your organism.
- Wear proper clothes according to season. During the cold one use thermal underwear – it will remove the moisture and will slow down the heat loss. An advice from personal experience: if it’s really cold and after a long ascends you’ll have to sit and wait on windy spot and you’re not sure in moisture-removal properties of your underwear use a cotton undershirt (as a “blotter”) worn between outerwear and underwear. Taking the undershirt off when on a spot you’ll reduce the heat loss.
- The colder it gets the more calories you need. Take enough high-calorie food and don’t forget about hot drinks. Climbing a mountain in winter you’ll sweat no less than in summer.
- Use special outer- and underwear with good breathing, wind-blocking and water-resistant qualities specially designed for mountain hunts.
- Watch your limbs when it is freezing hard. Low temperature blocks the sensitivity of nerve fibers and you can get frostbite without even feeling it.
