Hypothermia: Know The Signs That Can Kill You

With winter here, it’s time to gen yourself up on the dangers of running in the cold. Here’s the survival manual.

Linda Doke |

Hypothermia is defined as a medical emergency that occurs when the body loses heat faster than it can produce it, resulting in a dangerously low core temperature (not to be confused with hypERthermia, which is dangerously high body temperature).

Normal healthy core temperature for humans ranges between 36.6°C and 37.7°C. The body has a remarkable ability to regulate its operating temperature – simply put, we shiver when cold, and sweat when hot.
When we’re exposed to cold, the body activates three defence mechanisms to protect itself. The first is to readjust its energy expenditure by de-prioritising certain functions so it can focus on others.

Energy to the nervous system is reduced, so that the impulses to the muscles slow down. At the same time, more carbohydrates are burned to produce lactic acid. The combination of the two force the body to slow down to retain heat.

The second defence process is the constriction of blood vessels away from the surface of the skin to minimise heat loss. This reduces blood flow to the peripherals – the fingers, hands and feet, which explains why they’re the first to feel cold.

The natural reflex of shivering is the body’s third defence mechanism against cold. The rapid contraction of muscles generates heat and helps raise body temperature.

Risky conditions

Low temperature
This might seem an obvious one, but surprisingly, the temperature doesn’t need to be radically low to risk hypothermia. If a combination of factors are in place (see below), the air temperature can be as mild as 10°C for the risk of hypothermia to rear its head.

Wet plus wind
These two factors are notorious for conducting heat away from the body, even in hot conditions. Add any form of moisture – be it rain, snow, sleet or even sweat – to icy wind, and you have the perfect combination to cause rapid and dramatic loss in body temperature.

Slower pace or stopping
Providing you’re able to keep moving at a decent pace, you’ll be able to keep your core temperature stable. While your fingers and toes might be cold, if your torso is warm, you’re safe. If you’re forced to slow the pace, perhaps to assist a fellow runner who is walking – or worse, if you need to stop for whatever reason – your body temperature is likely to drop.


Exhaustion and extreme fatigue leave you vulnerable to a drop in body temperature. Physical depletion will mean your body simply does not have the means to expend energy on the three basic ways of keeping your core temperature stable.

Inadequate or inappropriate kit
The classic saying stands true: there’s no such thing as bad weather, only bad kit.

Symptoms of hypothermia

Every runner should equip themselves with at least a basic knowledge of how to recognise the first symptoms of hypothermia – in themselves and in fellow runners. There have been several examples in just this past year of runners becoming hypothermic, and being assisted by their fellow runners. Thankfully, all these cases turned out positively; but there was every chance they could have ended in tragedy.

Early stages
■ shivering is the first stage of impending hypothermia; from here, deterioration happens fast
■ speech becomes monosyllabic, slurry and impaired
■ loss of coordination, with a slow, stumbling step
■ confusion and poor judgment
■ drowsiness

Advanced stages
■ A desire to sit down or lie down, even if there’s snow on the ground (and even if the person knows it’s irrational)
■ Lowered heart rate
■ Shivering stops when the body temperature drops below 34°C; at this point the person may perceive their body to no longer be cold, and start stripping off layers of clothing

What to do to help others

When running in extremely cold conditions, be aware of not only your own condition, but also that of your fellow runners. Be on the look out for symptoms of hypothermia – and should you see them, act fast

■ Remove any wet items of clothing from the runner, and replace with layers of dry apparel
■ Wrap the runner in a space blanket
■ If possible, lie the runner on dry ground,sheltered from rain and wind
■ Lie close to (or, if necessary, on top of) the runner, to transfer your own body heat
■ If possible, get the runner to sip warm fluids

How to avoid hypothermia

Stick to these basic do’s and don’ts for running in cold or changeable conditions:

■ Wear layers of apparel, and be prepared to remove them and put them on again (repeatedly, if necessary) as conditions change. This will be particularly important when running in mountainous areas, where temperatures drop with altitude gain, and weather conditions are often unpredictable
■ Technical apparel only! This should go without saying. Cotton is out – technical fabric does not become heavy with moisture, and wicks the moisture away from your body
■ Ensure your rain jacket is properly waterproof (seam-sealed, and with a hood), rather than water-resistant
■ Warm headwear is essential, be it a fleeced beanie, a Buff, or a fleeced headband that covers the ears
■ Wear long tights if it’s cold. Even once wet, they help to reduce wind chill…
■ …but of couse, waterproof pants over your tights are first prize
■ Gloves are good for keeping wind chill off the hands. Once wet, though, you’re better off without them – they’ll only serve to keep your hands cold. (This does not apply in snowy and icy conditions, however, where risk of frostbite is high.)
■ Consume extra kilojoules during cold weather runs.

Salomon athlete Jock Green’s experience at the 50km Bastille Day Trail Run 2017

The background: the race is run in midwinter, in the mountains above the Berg River Dam behind Franschhoek, in the Western Cape. Mountains are notoriously unpredictable weather-wise; add the Cape’s wet winter to the mix, and you have what many Cape trail runners consider ‘real’ trail-running conditions.

That day, the weather was truly foul – there was rain, wind and cold. Jock was one of the front runners, contending for the win. Just 20km into the route, near the top of a 1 150m peak, Jock became hypothermic. He told me the story of his ordeal:

“Firstly, never trust the weather forecast for mountains. Right up until the start of the race the weather report for that day was mild, showing a minimum of 9°C with a slight chance of rain. What we often discount is the wind factor. As we reached the summit that morning the wind was blowing in excess of 60km/h, and the real feel was sub-zero.

“I made lots of mistakes that day. I underestimated how big that mountain really was. Worse than that, I showed the race distance of ‘just 50km’ no respect. Instead, I thought how hard can a 50km race really be? As ultra runners, our races only start after 60km!

“Considering how badly my body responds to cold conditions, I was completely unprepared for the weather that day. I had the usual, mandatory emergency race kit (thermal undershirt, rain jacket, buff, space blanket), but it was far from enough. I needed thermal tights, rain pants, proper gloves and a beanie, in addition to what I had in my pack.

“I started the race in really good physical condition, and with the event being a Salomon-sponsored race, my plan was to obliterate the field. I wasn’t going to let a bit of bad weather slow me down by having to put on my wet-weather gear early… and that was another huge mistake! A two-minute stop might have saved my race (and meant I wouldn’t have put my life in danger).

“As I climbed, I grew colder and became slower. I remember looking around for a place to shelter from that terrible wind, but that was yet another huge mistake. I found a large rock to shelter behind, and sat down to ‘get warm’. Fortunately, it was pretty close to the trail; and luckily for me, my fellow competitors found me.

“Then I learned the biggest lesson of my running career: every single one of the runners who came across me stopped – to help me, stay with me, give me whatever clothing they had at their disposal; and once I was stable, to offer any additional help that I might have needed.

“I passed out twice next to that rock. The second time I passed out, honestly, I was content to die. There was nothing left in me. The strange thing about that feeling was that I was actually content with my decision to give up – there was nothing more I could do, and I simply wanted everything to end.

“When I awoke, there was a runner rubbing each limb to get me warm, and one behind me, holding me. They’d pulled a pair of rain pants on me, three long-sleeved thermal shirts, three buffs and
a beanie.

“As I orientated myself, I realised that their stopping to help me was now putting them in danger of becoming hypothermic.

“Not one of the five guys who revived me would accept me telling them that I was okay, and that they should continue with their own race. Instead, they helped me stand up, and stayed with me as we made our way down. Only once we were safely off the mountain did they continue their race. And by that time, any chance of a good result for them had been sacrificed for me.

“I’ll never forget what the Erasmus brothers, Bradley Hyman, Steven Roberts, and a number of complete strangers did for me that day. I hope that one day I’ll get the opportunity to repay that favour by helping a fellow runner in need.”

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