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Icecold calculations: How much cold can we actually tolerate without it affecting our performance?

March 7, 2010
Researchers in Norway are gathering physiological data on how we react to cold. These data will give scientists the expertise they need to develop what they call "advanced protection" for persons who operate in our most severe climate zones, such as Siberia and the Arctic.

A Hans-Rudolf valve is inserted in Sindre Sandbakk's mouth; used in conjunction with a nose-clip, this produces a closed breathing system. The test reveals Sindre's maximum oxygen uptake capacity, and maps out where his lactic acid threshold lies.
Credit: Image courtesy of SINTEF

The general aim of the ColdWear project at SINTEF is to gather physiological data on how we react to cold. These data will give scientists the expertise they need to develop what they call "advanced protection" for persons who operate in our most severe climate zones, such as Siberia and the Arctic.

Among the products envisaged by the scientists are "intelligent" extreme-weather clothing. Technical clothing for elite athletes are also on the scientists' list of potential products that could see the light of day as a result of this project.

A total of 21 persons have been tested under six temperature conditions, ranging from + 20 to -25 degrees, in the course of the past six months. The scientists have also carried out tests of "manual capacity," which gives us an idea of what cold does to our ability to concentrate and perform fine motor tasks at different temperatures, a capacity that is extremely relevant to industry.

No other research team anywhere in the world has tested human subjects in extreme cold in this fashion. The figures obtained by the tests will soon be systematised, and the results will become a database of "cold" facts.

"The results so far show that cold has major effects on both fine and coarse motor capacity, which indicates that there is a real need for new clothing concepts," says Øystein Wiggen at SINTEF.

Extreme reality

Research scientist and ColdWear project manager Hilde Færevik pops in to the laboratory to make sure that everything is going according to plan.

"It is impossible to imagine what it is like to work in the harshest climate areas, where temperatures can fall to minus 60 degrees. What is clear is that there is a need for advanced protective clothing when you are working under these conditions. And work of this sort is necessary, because technical equipment needs constant maintenance in extreme cold. This is why the tests that we are carrying out just now are an important aspect of the ColdWear project," says Færevik, as she mentions some of the ideas that her research group in SINTEF is working on:

"It is quite impossible to imagine what it is like to work in these regions, where temperatures can fall to 60 below zero." says Hilde Færevik

"We are thinking of clothes made of functional materials which, for example, can store excess body heat that can be extracted from the garments when the temperature falls again. We are also developing clothing with integrated sensors that both monitor the person wearing them and communicate with the outside world," she says.

Færevik emphasises that the real world can produce far worse climate conditions than the scientists can simulate in the laboratory, so she hopes that SINTEF's efforts will be both useful and profitable. One third of the world's oil reserves are estimated to lie in arctic regions. The oil companies and contractors that begin to operate in these regions will face enormous challenges in terms of HSE, in addition to technical problems.

For this reason, part of the research project will consist of interviewing people who have lived under extreme weather conditions. Børge Ousland is one such person whom the scientists plan to interview.

"An arctic explorer like Ouslandhas unique experience that would be very useful for us," says Færevik.

An hour of hard work

The cross-country skier, Sindre Sandbakk, is sent into the treadmill, where today's task is to complete four runs of gradually increasing difficulty, before a final trial that will involve "giving everything" -- a maximum test to exhaustion. The test leader monitors the graphs on the computer screen closely. Nothing is left to chance; everything must go according to plan. If there is even a suspicion that something is wrong with the athlete, the test will immediately be broken off.

The treadmill has not been set up for a Sunday trip, but for aerobic exercise, and its ventilation fan, which is nearly a metre in diameter, will make sure that he has plenty of air resistance.

"All of the air that passes in and out of Sandbakk's system will be measured by this, which enables us to measure his oxygen uptake, how hard he is working and how much heat he is generating, " explains test leader Øystein Wiggen.

Now Sandbakk is warming up. Then comes the set of gradually increasing ten-minute "drags," each followed by a two-minute pause to enable a sample to be taken for lactic acid analysis.

The hunt for the perfect sensor

Meanwhile, five hundred kilometres away in Oslo, SINTEF ICT researcher Trine Seeberg is working on another problem: what is the best way of attaching sensors and electronics to textiles?

"We are thinking that we can integrate sensors into clothing that measures, for example, heart-rate, respiration rate, activity level, humidity and temperature, or various combinations of these."

The scientists believe that the data that are registered by the sensors could be coupled up to the wearer's mobile telephone, which in turn can send the information wirelessly to a control room. Sensors of this sort would enable the wearer's state of health and working conditions to be monitored, which would make it possible to interrupt a task if necessary.

"Monitoring will give us a picture of the level of risk run by people working under extreme conditions, such as in Russia's Shtokman field," says Seeberg.

However, developing measurement sensors of this sort is one of the major challenges that face the project: the electronics would have to withstand machine washing, wide swings in temperature and heavy-handed use. Some of the sensors would also need to be attached to the skin. Satisfying requirements of this sort is not done "just like that."

The scientists will also need to finds ways of supplying the electronics with enough power to enable the clothing to operate wirelessly for long periods.

"Bluetooth technology works fine, but anyone who has ever tried to transmit images from a mobile phone via Bluetooth has certainly found that the mobile loses battery power quickly, so we are working on electronics that are less energy-intensive than current systems," explains Seeberg.

Stretchable electronics

The electronics that are integrated into textiles must also be flexible, like the material itself. This means that traditional conductive wiring cannot be used. Research scientist Arne Røyset and his colleagues are working on making certain areas of the textiles conductive with the aid of polymer plastics. Most polymers are poor conductors, but they are flexible and more comfortable against the body than metals.

The scientists are also looking at how to connect up two different polymer materials so that together they become a temperature sensor. This is done by exploiting the thermoelectric characteristics of the materials. A difference in temperature between two locations can generate a tiny voltage, and such voltages can be measured.

"The challenge involves finding combinations of materials that have high thermoelectric capacity and good conductivity, and that are stable and robust," explains Arne Røyset.

Microscale transport

Røyset's team are also studying the ability of textiles to transport humidity and heat. This is being studied at microscale, because it is at this scale that these properties lie, he explains, pointing out the unique capabilities of woollen fibres as an example of nature's own high technology: the material is both an excellent heat insulator and transporter of heat away from the body. These are properties of the nanostructure itself.

"Some materials changes their properties according to the conditions of temperature or humidity. This means that we can envisage a piece of clothing that is a good insulator when it is cold and a poor insulator when it is hot," says Røyset, and continues: "With demanding work in the cold, where work intensity and the ambient temperature vary, such a material would help to increase work capacity and safety at the same time as it provided better comfort.

Acid test

Back in the laboratory, Sandbakk is gearing up for his final effort. His lactic acid level is high, and his powers are beginning to fade. The assistant gives him a final encouraging call, before the figures on the computer screen offer their unambiguous verdict. Øystein Wiggen breaks off the experiment at three minutes to ten; he has the information he needs.

In the service of research, our excellent guinea-pig is exhausted but satisfied. Thirteen biocompatible sensors still have to be removed from his body, before he can take a quick shower. For Wiggen and his colleagues, there is still a good deal to do before the end of their working day. The scientists can now add the results to their database, which will bring them a step closer to the answer of what we can manage to do in the cold. That is a cold fact.

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SINTEF. "Icecold calculations: How much cold can we actually tolerate without it affecting our performance?." ScienceDaily. ScienceDaily, 7 March 2010. <>.
SINTEF. (2010, March 7). Icecold calculations: How much cold can we actually tolerate without it affecting our performance?. ScienceDaily. Retrieved April 27, 2017 from
SINTEF. "Icecold calculations: How much cold can we actually tolerate without it affecting our performance?." ScienceDaily. (accessed April 27, 2017).