Dealing With Cold
Many people hate the cold. They shiver when the temperature in the house drops below 20 degrees and don’t venture outside at all when temperatures reach freezing. How we perceive temperature is a complex physical and also mental process, which is often highly personal. When winter camping it helps to realise that comfort and air temperature are not as closely related as we often think. As long as our body stays at a normal 37 degrees, we can live comfortably in much lower temperatures than we think. But where are our limits?
This article is the fourth in a series of articles about winter camping. See the index of all parts below.
Active in extreme cold
Guest article by Kees Floor, Dutch meteorologist. Translated from Dutch and republished with permission
Since 1996, there have been no extremely cold days in the Netherlands. According to the climate models of the Royal Dutch Meteorological Service KNMI, climate change reduces the risk of extreme cold. Nevertheless, now and in the future, a bitterly cold day can still ‘slip through the cracks’. Will we then be advised by meteorologists or the government to stay indoors? How would we deal with that? Will we be unable to go to work, no longer receive our daily newspaper or mail, will there be no police in the streets, will we cancel our daily run and crawl into bed and stay inside near the heater?
‘There is no need to worry’, says the American College of Sports Medicine. ‘Being in the cold doesn’t mean being cold’. ‘Cold is almost never an obstacle for exercising outside, participating in competitions, actively recreating or going to work’, the conclusion reads. Mail deliverers, construction workers, employees of the park service and police officers can attest to this, even though working outside in a bitterly cold eastern wind is no fun. Incidentally, the American authors of the advice add some conditions: ‘Those involved and their coaches or managers must inform themselves of the expected conditions, be aware of the risks and, depending on health and physical state, adjust their clothing and take other measures against the cold. Athletes and outdoor workers also need to know what to do if conditions deteriorate.’ In addition, the sports scientists recommend: ‘If necessary, shorten your training and make sure you are always near a place where you can warm up again.’
Many of these recommendations are actively used by the Royal Dutch Marines, who regularly hold cold weather exercises in the north of Norway, in extreme cold. ‘But our men can’t always go back to a protected environment and are often on the road for days’, says Captain Friso Amsterdam. “They are then outside for a long time, carrying 30 kilos of luggage, a weapon and a sled with tents, more weapons, ammunition and food. The only shelter they have are the tents or self-built igloos, in which the temperature is a balmy zero degrees. Everyone needs to know exactly how to dress and make sure they continue to eat and drink well.” Food provides the energy to keep metabolism and heat production going, keeping the body temperature up. Drinking is necessary to replenish the fluid that is sweated out during great exertion.”
Working in the cold
When is it actually so cold that you really have to take this kind of advice to heart? Amsterdam thinks of at least 10 below zero, or better yet minus 20 degrees centigrade. Eric Hoeben, who as a company doctor of ‘Arts in Bedrijf’ regularly visits cold stores, keeps temperatures of minus 10 to minus 15 degrees as a limit. ‘There are rules for rest and working hours for working under these conditions’, he says. ‘These special rules apply if you work more than four hours a day in such a cold environment and also prescribe that you should never work in that cold for more than an hour at a time. After that, you have to spend at least half an hour in a place where it is twenty degrees warmer.’
In construction, different thresholds are used to whether or not to work in the cold. ‘A construction worker may stop working in the open air when it is freezing and the perceived temperature has a value of minus 6 degrees or lower’, we read on the website of ‘Vorstverlet Opgelet’.
‘If there is hardly any wind, the perceived temperature is equal to the prevailing air temperature. But with some wind or drafts, it immediately feels colder, because the body loses more heat’, explains information officer Harry Geurts of the KNMI. ‘We can express that heat loss in a kind of sensed value of the temperature, which we refer to as perceived temperature. At wind force 4, one degree of frost is enough to get a perceived temperature of minus 6, at which construction workers will move indoors or go home.’
Such an arrangement seems simple and unambiguous, but there is still a catch, according to the words of Oscar Enschedé of Weathernews. This company provides weather reports for the construction industry. This includes the perceived temperature, which is often missing in normal weather reports. ‘We always talk afterwards and about standard conditions,’ says Enschedé. ‘For example, we can conclude that one or two hours ago, according to the current agreements in Soesterberg, it was just possible to work at a height of one and a half metres. But what about a construction site in nearby Bunschoten, where the site is more open and the wind blows harder? In addition, the wind increases with altitude. A few floors up in a flat under construction the work will therefore have to be stopped earlier than on the ground floor. Discussion and disagreement about whether or not to work remains possible’.
Unpleasant or dangerous?
Skaters, cross-country skiers, joggers and other athletes who brave the cold at their own free will to practice their hobby, probably care little about these kinds of strict rules. Researchers participating in polar expeditions or conducting research into ice cores in freezing laboratories also appear to have little need for regulation. But for those who have to earn such a living – daily in freezers or occasionally in the open air – it is different. ‘Working in the cold is not only unpleasant, but can also be dangerous’, says Hein Daanen, researcher at TNO and professor of thermo-physiology at VU University Amsterdam. ‘First there is the unpleasant feeling of cold. The moment at which that begins to occur is strongly individually and culturally determined. If the temperature drops further or the cold lasts longer, the perform manual tasks decreases. As a result, the risk of accidents increases and eventually more serious issues can arise in the musculoskeletal system. For example, in a study, workers from cold stores were found to show many more joint problems than colleagues who did the same work in a normal warehouse.’
Corporate physician Hoeben further expands the list of issues of workers in cold stores: ‘Muscles cramp when transitioning from hot to cold and blood becomes more viscous than normal. That in turn leads to things like acute back pain, stomach issues, sinusitis, thrombosis, anything that has to do with cardiovascular problems. Not always of course,’ Hoeben puts into perspective, ‘but there is an increased risk.’
Hypothermia and frostbite
For the Marines, hypothermia and frostbite are the biggest threats. ‘You have frost nip and frost bite’, Captain Amsterdam explains. ‘Frost nip is a superficial frostbite, in which the skin becomes slightly discoloured and hardened.’ Frost bite turns out to be more serious: ‘the skin turns dark and begins to die.’
The aforementioned advice from the American College of Sports Medicine contains some statistics. At air temperatures of minus 15 degrees, the chance of freezing the skin is less than five percent. However, if the perceived temperature falls below minus 27 degrees, skin exposed to the cold can freeze within half an hour. In people with dark skin, the risk of injuries from the cold is two to four times higher than in white people.
Cold war inside your body
In order to prevent this kind of ‘frost damage’, the captain of the Marines informs his soldiers of the dangers: ‘The climate is your biggest enemy. Arming yourself against this has first priority. Fighting against any other opponents comes second.’ As a weapon against the cold, the Marines have a standard arctic equipment kit with more and better insulating clothes than standard issue, thicker gloves and face protectors. During heavy exercise – ‘our people also perform top sport’ – clothing is more likely to become damp due to sweat, which then leads to more cooling. The troops are instructed to regularly change into dry clothes to better enable the body to keep itself at temperature.
‘It’s also war in the body itself’, says Professor Daanen. The battle rages between the core and the extremities, such as fingers and toes. ‘If the core threatens to become too cold, the body stops the supply of heat to the limbs as a survival strategy. As a result, you have a greater chance of cold injury to fingers or toes. Body preservation is more important than the discomfort of missing a finger, is apparently the underlying idea.’ However, Daanen points out that hypothermia does not always have to lead to death: ‘Hypothermia is less threatening than is often thought. Don’t write off someone who is hypothermic too quickly: “You are only dead when you are warm and dead”, is his motto. If the body temperature falls below 35 degrees you speak of hypothermia. However, there is this case of a woman who had cooled down to just under 14ºC, did not give any more signs of life, but eventually made a full recovery after warming up.
Alcohol is taboo in the army nowadays, but Daanen can still say something about it: ‘It lowers the shiver response, which produces body heat, but increases the feeling of comfort.’ Hence his advice-with-wink for when you are stuck in the cold during an expedition with a bottle of liquor in your pocket: ‘Do not touch the bottle as long as there is still some chance of rescue; only drink it when there is no more hope of survival.’
Just go outside!
So you won’t easily die of extreme cold. “Extreme cold does not have to be an obstacle to physical activity. Numerous successful and safe polar expeditions are proof of this,” says the American College of Sports Medicine. What about those victims about which the media report every year after a cold outage in the United States? “They mainly fall under people who take irresponsible risks or among members of vulnerable groups who cannot defend themselves against the cold,” says American meteorologist Edwin Kessler, annoyed by the many exaggerations in the media. Just go outside!