Hypothermia prevention and treatment

Winter is beautiful. But beware the dangers, too. Pic credit: Andrew Magill on Flickr

Winter is beautiful. But beware the dangers, too. Photograph: Andrew Magill on Flickr

All you need to know about hypothermia when walking or running in the mountains.

Hypothermia is a tricky and deceptive condition. It can creep up without victims noticing, and can be a killer in the mountains.

According to Scottish Mountain Rescue, hypothermia is frequently the prime cause of call-outs.

Ian Dawson, a long-standing volunteer with Lomond MRT, says: “Even during the warmer months of the year, let alone the winter, the inability to walk off the hill, as a result of exhaustion or injury, means many casualties will commonly show some degree of hypothermia.

“In fact, most winter mountaineers will often be mildly hypothermic during points of their day. It is also a common contributory factor in many fatalities. We treat everyone that we rescue for hypothermia with warm drinks, food, bothy bag and foam mat.”

First signs of hypothermia

When stable, our core body temperature is around 37°C. As the heat leaves the body we will experience symptoms such as shivering. This is our body’s way of telling us to put on extra clothes, or to eat something for extra energy. At this stage, most people recognise the symptoms of the cold and make enough changes to keep themselves safe.

The problem occurs in the hills and mountains if you have been working hard, such as running or walking fast, and you don’t notice the drop in your body temperature until it’s too late.

It could be that you have moved quickly from a lower area to a higher and more exposed position and you do not realise how much the air temperature has dropped. Another danger point is when people stop for a rest at higher altitude – where they are less protected from cold temperatures and wind-chill – and suddenly realise they are shivering.

In some cases people haven’t realised how cold they have become and have not made the right decision to add clothing. For example, you might be thinking: “I’ll just get to that next hill or I’ll catch up my walking friends, and then I’ll put on more clothes.”

Cold hands and feet, a lack of food and drink and general tiredness can all lead to a drop in core body temperature.

When do you become hypothermic?

It’s important to know the signs of hypothermia so you can help other people. Most commonly it is someone else who will notice that you are acting a little differently.

For example, the classic signs of hypothermia are:

  • Shivering, sometimes uncontrollably
  • Poor decision-making
  • Lack of concentration
  • Tiredness
  • Irritability with those around you.
  • Fast breathing (hyperventilating), even when at rest

This is classed as Mild Hypothermia and occurs when the core body temperature dips to around 35°C.

The next stage is called Moderate Hypothermia. This occurs when the body temperature drops to around 28°-32°C. Symptoms include:

  • Confusion
  • Lack of concentration
  • Loss of judgement and reasoning
  • Difficulty moving around
  • Loss of co-ordination
  • Sleepiness and sudden fatigue
  • Slurred speech
  • Slow and shallow breathing

This is also when something strange, but very alarming, occurs. People who are increasingly hypothermic will stop shivering. The reason is that the body starts to focus on survival rather than fighting a battle and draws blood to its core.

Sadly, when the shivering stops many people believe that the body is warming up. It’s a bad mistake to make. This is when severe hypothermia takes a grip.

Hypothermia will be a very real risk if you are, for some reason, caught out in bad weather or if someone in the group suffers an injury.

The next stage – severe hypothermia

Below 28°-32°C, victims are heading towards severe hypothermia. At worst, consciousness can be lost and the heart rate becomes irregular. Bizarrely this is the stage when hypothermic victims will try to strip off their clothes, complaining of being too warm.

This happens because the body no longer has the energy to make the muscles work to generate heat, so it stops trying. The blood that has been stored in a bid to keep the core body warm is then released into the circulatory system.

The victim feels unbearably warm and will try to shed clothes. If this happens and the body temperature drops to 28°C, cardiac arrest is a near certainty.

Severe hypothermia symptoms to look out for in others are:

  • Pale and clammy skin
  • Unconsciousness
  • Shallow or no breathing
  • Weak, irregular or no pulse
  • Dilated pupils
  • Blue fingers and lips
  • Severe incoherence and irrationality

When severe hypothermia sets in, the blood cools and becomes denser (more viscous) and is less able to transport oxygen. A lack of oxygen means the body can’t metabolise sugars so energy levels drop further.

As the cooling continues, hypothermic victims typically become incoherent, irritable, unco-ordinated, irrational and clammy to touch. Fingers and lips will also turn blue.

Someone with severe hypothermia, and who is unconscious, may appear to be dead. A pulse may be hard to detect. However, under these circumstances the individual must be taken to hospital to determine whether they are in a state of severe hypothermia. Amazingly, medical treatment can sometimes still save a life at this stage.

Prevention is better than cure

The most obvious way to avoid hypothermia is to prevent it happening in the first place. Check weather forecasts and be sensible about where and when you walk or run.

Wear the right clothes for the conditions and take spares with you. This is particularly important for walkers and runners who like to travel light. In winter, this really isn’t an option if you plan to be out all day or at higher altitude.

Waterproof, windproof and insulated are key words for winter walking and running clothing.

Pay attention to the extremities, especially head, neck and hands. Wear good quality gloves (and take a spare pair), wear a hat and make sure you have suitable winter footwear. A buff is perfect for the neck area.

Ensure you are properly fuelled and hydrated before and during a mountain outing. Carry more food and drink than you think you’ll need.

Eat and drink whenever you feel the need, or at least every hour, and don’t leave it “just until I get over there”.

Carry a bivy bag, survival blanket or some kind of shelter, as well as energy gels and an emergency down jacket. If someone gets into trouble you will need all of these to help them to survive.

What can you do if hypothermia strikes?

Hypothermic victims typically require help from someone else but it’s vital that those who come to their aid do not also put their own health in danger. If a walking or running friend is in danger of hypothermia, you could be, too.

Stay warm: Put on dry clothes, find shelter, and insulate the body from the ground.

Refuel: Eat high-energy foods, rehydrate and, if possible, sip warm fluids, such as tea.

Get off the hill: Once you feel it’s safe, try to walk lower down the hill and get off as quickly as you can.

Warm up slowly: Applying direct heat, such as sitting on a radiator or next to an open fire, is not recommended. You need to warm the body up more slowly.

Warm and sweet: Drinks, high-energy food and gels will help to replace lost energy and warm from the inside out. Never offer alcohol or caffeine-heavy drinks.

Give a hug: This might sound odd but a hug and words of encouragement can help with recovery.

Gentle rubbing: In severe cases, over vigorous rubbing of the skin to “warm up” patients can lead to a cold blood to rush to the heart and brain. This could cause cardiac arrest.

Call emergency services: Know how to make contact with Mountain Rescue.

Get to hospital: In the worst cases, and especially when the victim has lost consciousness, you need to get them to hospital. Even if you can’t find a pulse all might not be lost. Survival rates from hypothermia can still be quite high even for those found with no apparent signs of life.

Further reading Stay safe in the winter hills

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