SAS Urban Survival Handbook (86 page)

REMEMBER

DON′T walk alone in unfamiliar territory – especially in extreme cold or heat. If you must, then tell someone where you are heading and when you expect to be back. All sorts of unforeseen hazards await the unwary rambler – from sudden mist and storms, wild animals, falls, all forms of attack to simply getting hopelessly lost.

Acclimatization

When you transfer yourself suddenly from a temperate climate to tropical heat, your body does not rise in temperature. Conversely, your temperature doesn’t fall in extreme cold. Instead, the ‘heat regulator’—the hypothalamus—situated in the brain, springs into action to acclimatize your body. It is thought to take up to six weeks for full acclimatization to be complete, but most of the changes occur within the first two weeks.

What are the changes? The resting temperature of your body actually falls, encouraging your glands to sweat more copiously for longer periods, starting at a lower temperature. It is the evaporation of the sweat which increases the heat lost by the body.

Heat is also transferred from inside the body to the surface at a higher rate, in order that heat can be further lost via convection. That happens through an increased flow of blood to the skin, and dilation of surface blood vessels starting at a lower temperature.

Factors that slow the rate of acclimatization are age, fatigue and obesity—and a low testosterone level (the male hormone that stimulates sweat). In other words, an overweight female pensioner, tired from a long journey, is going to feel uncomfortable! Here’s how to help YOUR body adjust:

Heat

The MOST important step is to increase your intake of fluid. It is essential that your body sweats sufficiently—you MUST constantly replenish the water (and salt) lost in this way. Drink two litres, plus one, per 10°C (one pint of water per 10°F) EVERY 24 HOURS. Yellow-coloured urine is a sign you are not drinking enough.

It isn’t often that you’re advised to eat more salt, but your body requires around double the normal amount in tropical heat. NEVER raise your salt intake without increasing your fluid intake accordingly. NEVER rely on any alcoholic drink to replenish your fluid levels.

WARNING

Nylon and other man-made fibres are the WORST things to wear. They barely absorb moisture, and you can end up with the extremely uncomfortable skin rash, prickly heat, because you’re living in a pool of sweat.

Since it is necessary for the sweat to evaporate to keep the body cool, what you wear is important. Loose (to trap a layer of air) light clothing made of absorbent fabric is the rule—white cotton is by far the best choice. Cotton absorbs 50 per cent of its weight in water. White clothing reflects the light, reducing the solar heat load by up to a half.

Sun

These days, much publicity is given to the dangers of excessive sunbathing—to the extent that one is less likely to feel envy for a white-skinned person burnt to that once-fashionable nutbrown colour. The link between sun exposure and skin cancer has now been proven, and the incidence of malignant melanomas in temperate countries has been rising at a rate roughly equivalent to the spread of mass tourism.

WARNING

If you WANT skin cancer, statistics indicate that all you need to do is work in an office for 50 weeks a year, then lie on a beach for the other two—preferably using tanning oil that offers insufficient protection and acquiring a nasty case of sunburn in the first few days. Anyone with red or blonde hair and/or a freckled skin will be particularly susceptible.

Sensible tanning

• ◑ Use a high SPF (sun protection factor) cream or lotion on ALL exposed parts for the first few days, changing to a lower SPF only once your skin has darkened.
  
• ◑ REMEMBER! The SPF levels of sun preparations are not standardized. One company’s factor 15 might be the same as another’s factor 32.
  
• ◑ Especially if you’re fair skinned or unused to the sun, consider a total sunblock for vulnerable areas (bridge of nose, knees, shoulders, breasts).
  
• ◑ REMEMBER! Burning rays reflect off water, snow and white sand, intensifying their effect. Always use waterproof lotion for swimming, since the rays penetrate several feet below the surface.
  
• ◑ The sun can burn even through glass, clothing and in shade. A cloudy sky is not a protection against sunburn.
  
• ◑ ALWAYS build up your sun exposure time gradually. 15 minutes is quite sufficient for the first day, especially if it’s winter back home. In general, you can double your exposure time daily, but use your common sense! YOU know how your skin reacts to sun.
  
• ◑ NEVER go out in the midday sun! In fact, avoid it between 11 am and 2 pm.
  

  

  WARNING
  

  SUNSTROKE/HEATSTROKE: Normally this unpleasant condition is heat syncope, or heat collapse, brought on by sudden, prolonged exposure to heat and is not serious. Symptoms of the mild form are dizziness, fatigue, nausea and fainting, possibly accompanied by blurred vision and yawning. Treatment is rest in a cool room and plenty of fluids.
  

  Heat hyperpyrexia, or heatstroke, however, is far more serious and potentially life-threatening if untreated. The body temperature rises to 40-41° C (105-106° F) due to the failure of the heat regulation mechanisms, sweating stops and the patient loses consciousness.
  

  The moment you suspect hyperpyrexia, SEEK URGENT MEDICAL ATTENTION. Cool the casualty, preferably by spraying with cold water in a stream of dry air, or by wrapping in a wet sheet or immersing in a cool bath. It is VITAL to take the casualty’s temperature (rectally) every five minutes or so and STOP the cooling procedure as soon as it drops to 39°C (102°F).
  

  The casualty MUST drink plenty of water and take salt. This can be given intravenously if unconscious. This condition tends to be rare in the ordinary traveller – expatriate manual workers in hot climates are most at risk.
  

• ◑ NEVER fall asleep in the sun. Sunburn is dangerous, especially if the skin blisters. The medical names for sunburn are acute actinic dermatitis and solar erythema—let that put you off!
  

Humidity

You sweat just as much in dry heat, but the sweat evaporates. In a humid climate, the atmosphere is all but saturated with moisture already and can’t absorb much extra. This means your sweat stays with you, and you may believe you’re sweating more copiously. You’re not.

A relative humidity of 40-70 per cent is generally agreed to be comfortable for humans, with an air temperature of 15.5- 27° C (60-80° F). Mogadishu (Somalia) has a maximum relative humidity of 81 per cent; Bahrain, 89 per cent; Mauritania, 91 per cent; and Oman, 94 per cent! Top of the hell-on-earth league, though, is the United Arab Emirates, where it is possible for the air to become saturated to the maximum—100 per cent relative humidity.

Altitude

Several important cities are at or higher than 1830 metres (about 6000 feet) above sea level—for instance, Nairobi, Johannesburg, Bogota and Mexico City (the most populous city in the world, incidentally, with some 19 million inhabitants). On arrival, you will undoubtedly find you are shorter of breath than usual, owing to the rarified atmosphere—there is less oxygen in the air.

Tolerance for altitude varies considerably from one person to another, but the symptoms of ‘mountain sickness’—headache, nausea and shortness of breath—are very unlikely to appear in anyone below 3050 metres (10,000 feet).

The body copes with altitude by making new blood cells to enable you to take in more of what little oxygen there is—this process takes up to three weeks. So, even if you feel quite well, you should NOT exert yourself when you arrive. The British athletes at the 1980 Olympics were brought to Mexico City—which is 2255 metres (7400 feet) above sea level—four weeks before the Games and were forbidden to train at all for the first four days to allow their systems to adjust.

Cold

In a very cold climate, the small arteries (arterioles) become restricted, reducing the flow of blood to the surface in order to maintain warmth. This increases the blood pressure, meaning that the heart works harder and needs more oxygen. Angina sufferers feel worse in the cold, and those with arteriosclerosis (hardened arteries) will suffer freezing cold feet and hands, since the blood flow is impeded.

In extreme heat, loose clothing traps a layer of air and encourages perspiration. In the cold, you should also wear loose clothes—this time to trap warm air. The rule is, wear several layers—you stay much warmer than with one thick jumper. Clothing should be close fitting, but not tight enough to restrict movement or prevent that insulating layer of air.

Don’t wear TOO much. If you sweat profusely, the moisture can freeze. Equally, ensure that your outer clothing always stays dry. Extremities (toes, fingers and especially ears) are prone to frostbite.

Time zones

Aside from climate changes, the traveller has to cope with readjusting to different time zones. It’s a peculiar fact of modern life that you can now get around the world so fast that you can live through a few hours twice, or never have them at all.

The internationally-agreed time change line is drawn along the 180° meridian, zig-zagging around lands in the Pacific. For every 15° of longitude, the time changes by one hour—backwards (or behind Greenwich Mean Time), to the west and forwards (ahead of GMT), to the east.

As we now know, the ‘unnatural’ speed of travel across time zones upsets your body clock. Apart from this problem of jetlag ALWAYS take into consideration the time at which you will reach your destination. It is not fun to arrive exhausted in a strange city in the small hours after a 12-hour flight!

Jetlag

Flying across time zones disturbs not only your sleep patterns, but also your pulse rate, body temperature, reaction time and decision-making abilities. Bowel movements and urination times are usually affected too, possibly leading to temporary constipation and further disturbance of sleep through having to get up in the night to urinate.

It has been proven that jetlag is twice as bad after eastbound flights than westbound, whatever the time displacement. Flying north-south has no effect apart from the normal journey fatigue. Jetlag is not usually dangerous, it’s more a case of inconvenience.

MINIMIZING JETLAG

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  Time your journey so that you can go to bed as near to your ‘old’ home bedtime as possible
  
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  DON’T make decisions or enter an important meeting straight after arrival.
  

  Your faculties will be greatly impaired
  

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  Try to take it easy for the first 24 hours after arrival
  
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  Use an aperient and/or mild sedative on arrival for constipation and insomnia ONLY if absolutely necessary
  
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  Diabetics should take their meals and administer insulin injections at the ‘old’ time during long flights, then change their routine on arrival. Always notify the airline in advance