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Exposure to Cold & Altitude


The major risks to people exposed to the cold are: general body cooling leading to hypothermia (exposure), and local cooling, primarily affecting the hands and feet (chilblains & frostbite). Those at greatest risk are the ill prepared.

Visitors to cold climates should be aware of the condition known as hypothermia which is caused when a person's internal body temperature falls below normal (37C). It is likely to happen on cold, wet, windy days to people who are poorly clothed, hungry and tired.

Cold conditions are exacerbated by wind where the temperature is effectively lowered and it appears to be much colder than it actually is. This phenomenon is known as wind-chill.

Hypothermia is a dangerous condition and is often accompanied by mental confusion where the person affected does not realise what is happening preventing them from seeking help. Extreme hypothermia can lead to death in just a few hours.

Prevention of hypothermia is achieved by the use of appropriate clothing including hat, gloves/mittens, suitable socks and boots. There is an abundance of excellent protective clothing available for outdoor enthusiasts. Specialist advice should be sought as to the best equipment for a trip, including survival equipment. Loss of articles of clothing in an accident can be disastrous unless spares are carried.

Symptoms of Hypothermia include:

  • Uncontrolled shivering followed by
  • Confusion & dizziness
  • Slow, clumsy movements and difficulty in walking
  • The person feels tired
  • Breathing becomes shallow and pulse becomes slow
  • Loss of consciousness

Treatment of someone suffering from hypothermia entails preventing any further drop in body temperature. This involves seeking shelter, insulating and protecting them from the cold environment. Replace any wet clothing with dry ones. Make sure the head, feet and hands are covered. Place the person in a sleeping bag with another person. Give them warm drinks and high energy foods (sweets, chocolate etc.) Avoid rapid re-warming unless the victim is well and conscious.

Chilblains (non-freezing cold injury) occur in cold, damp conditions where the hands and feet are cold (and generally wet) for extended periods. They are characterised by itchy or painful swellings that can lead to open sores if left untreated.

Frostbite is freezing of the skin and surrounding tissues and can occur in anyone exposed to temperatures below freezing without adequate protection. Frostbite should never be defrosted if there is a likelihood of re-freezing as this will greatly exacerbate the problem.

Prevention of these conditions is achieved by maintaining adequate insulation from the cold by the use of appropriate clothing, keeping the extremities warm and dry and by consuming high energy foods and warm drinks.

Being attentive to early signs and symptoms is important. If frostbite is suspected the casualty should be referred for medical help as soon as possible.

In all suspected cases of exposure to a cold environment:- AVOID ALCOHOL


The problems associated with high altitude are usually only manifest in people who have been to altitudes in excess of 3,000 metres (10,000 feet).

The main concerns associated with high altitude include:-

Cold: is a factor generally experienced at altitude. As a rule, the higher you climb, the colder it gets. The risks and precautions that need to be taken with regard to the cold are covered in the previous section.

Dehydration: It is very easy to become dehydrated at high altitude due to the dryness of the air and by water loss in sweat caused by exertion. In order to prevent dehydration, it is important that you drink as much fluid as you can while in the mountains, (about 3 litres per day). The best way to determine if you are getting enough fluid is by urine output. It should be colourless or pale yellow. If it is bright yellow or orange, you are not drinking enough.

Sunburn: At higher altitudes the sun's harmful ultraviolet rays are more concentrated. You must protect yourself against these rays by using sunscreens or sun blocks. You can also use hats, scarves and masks to protect your face and neck. Remember, even if it is not hot, you can get severely burned. For more information, see the section on exposure to the sun.

Snow blindness: Snow and ice both reflect ultraviolet rays. These rays can damage your eyes causing pain, watering and swelling and an intolerance to light. This condition is known as snow blindness and can be very painful. Fortunately it is short lived and recovery is usually complete after a few days. It can prevented by using adequate protection such as sun glasses or goggles.

The Golden Rules of Altitude Sickness

  • It is OK to get altitude sickness but it is not OK to die from it.

  • Any illness at altitude is altitude illness unless proven otherwise.

  • Never ascend with symptoms of AMS.

  • If you are getting worse, go down at once.

  • Never leave someone with AMS alone.

Acute mountain sickness (AMS) is the term used to describe the most common symptoms which include; headache, nausea, dizziness, loss of appetite, vomiting and insomnia. If these symptoms are ignored and the affected person continues to ascend, more serious conditions such as High Altitude Cerebral and/or Pulmonary Oedema (HACO & HAPO) both of which are life threatening can result.

Avoidance of mountain sickness is best achieved by a slow ascent and by maximising the opportunities to acclimatise.

The appearance of any of the above symptoms should prompt consideration of a descent, or at least the decision not to go any higher until they resolve.

Continued symptoms should result in a shift to a lower altitude. By spending the night at a lower altitude than the highest attained during the day is helpful - Climb High Sleep Low.

Prophylactic acetazolamide has been effective in preventing altitude sickness in susceptible travellers, or when time for natural acclimatisation is limited but it does not protect against cerebral or pulmonary oedema.

Note on Lariam and altitude
Lariam (mefloquine) is an anti-malarial drug used in areas where resistance has developed to chloroquine. Sometimes travellers intending to climb to altitude must pass through such areas e.g. Kilimanjaro which is located in Tanzania.

Because of certain properties of lariam it is now contraindicated in people travelling to high altitude. Apart from predisposing people to mountain sickness, some of the side effects actually mimic the symptoms of mountain sickness and therefore make diagnosis difficult.

Preventing Acute Mountain Sickness

Acute mountain sickness is caused by a lack of oxygen when travelling to higher elevations. This usually occurs in individuals exposed to an altitude over 7,000 feet (2,100 m) who have not had a chance to acclimate to the altitude before engaging in physical activities.

Mountain climbers, trekkers, skiers, and travellers to the Andes or Himalayas are at greatest risk. While individual tolerance varies, symptoms usually appear in several hours, with those in poor physical condition being most susceptible.

Headache, fatigue, shortness of breath, nausea, and poor appetite occur initially. Inability to sleep is also frequently reported. In more severe cases thinking and judgement may become impaired. An uncommon but potentially fatal complication called high altitude pulmonary oedema, caused by fluid build-up in the lungs, can also occur.

The symptoms of acute mountain sickness can be prevented or minimised by gradually ascending (less than 500 meters/day) over several days to give your body a chance to acclimatise to the higher altitude. Once symptoms occur, they usually improve over several days without treatment. However, if they become severe, they can be relieved with the administration of oxygen or descent to a lower altitude.

Acetazolamide (Diamox) allows your body to metabolise more oxygen, thereby minimising the symptoms caused by poor oxygenation. This is especially helpful at night when the respiratory drive is decreased.

It is advisable to start taking it 24 to 48 hours before you go to altitude and to continue treatment while ascending until you have fully acclimatised to your final altitude.

The recommended dose is 250mg (one tablet) twice a day when required.

Possible side effects include tingling of the lips and fingertips, blurring of vision, and alteration of taste. People with a known allergy to it should not take it.

Acetazolamide (Diamox) is a prescription only drug so you need to contact your doctor for a prescription to obtain it.

For more in-depth information
on Altitude Sickness

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