Exercise in a Cold Environment and High Altitude

Exercise in a cold environment and high altitude

Performing exercise in cold environments has been done since the human race set its foot on the northern hemisphere and had to survive the first winters. In more modern time, performing exercise in cold environments where the temperature sinks below zero degrees has, for certain sports and certain parts of the world, become common and seems like a normality. However, training in a cold environment comes with risks and challenges, which the athletes and/or coaches have to deal with. An early example of exercise in extreme cold is the race to the South Pole between Roald Amundsen and Robert Falcon Scott where they were exposed to temperatures as low as -50 degrees centigrade. Today, winter sports such as biathlon, alpine skiing and cross-country skiing are all undertaken under environmental extremes, which means multiple factors (e.g. nutrition, injury prevention, temperature regulation) have to be taken into consideration when planning training and competition (Meyer, Manore and Helle, 2011). Exercising in extreme environments, both cold and hot, is an important aspect in international sport and for coaches, it is important to know how to protect and develop athletes. A common perception is that exercising in a cold environment is harder and more dangerous than when performed at higher temperatures and can lead to injuries/discomforts during and after it is performed (e.g. a burning sensation in the lungs and stinging in the throat and nose) (Pavlik, 2012). This review of literature has two aims, the first is to look at what type of research is already out there on the topic exercising in cold environments and high altitude training (nutrition, injuries and performance) and the second is to give the reader an indication on how to best prepare an athlete for exercise in these environments.

Nutrition

When performing exercise in a cold environment there is often also a higher altitude involved than there normally is for sports such as soccer, rugby, hockey and other popular summer sports. With the high altitude, new issues can occur. The cold environment combined with high altitude suggests that winter sport athletes have to take the accumulative effects of low temperature and altitude into consideration when it comes to energy spending, fluid loss and nutrition intake, as a lack of this may result in injuries (Meyer, Manore and Helle, 2011). Current research on the area of exercise in cold environments and/or altitude (e.g. Meyer et al., 2011; Clark, 2012; Castellani, Young, Ducharme, Giesbrecht, Glickman and Sallis, 2006; Burke, 2005) suggests exercise in low temperatures may increase energy requirements. However, there is not a specific answer to what the main reason for the extra energy expenditure is. Clark (2012) suggests that by exercising in a cold environment the body temperature drops to a lower level than normal and the body uses its own defence mechanism, shivering (involuntary muscle tensing – creates heat – requires more energy). Whereas Castellani et al. (2006) and Burke (2005) propose the increase in energy requirements depends on the thermoregulation, how protective clothing manage to maintain the skin and core temperature and the body’s physiological response to a change in temperature. Another consequence of exercising in a cold environment is a reduced thirst (Clark, 2012; Burke, 2005). Due to a low temperature the feeling of being thirsty is lowered, despite sweat loss. Combine this with the fact that aerobic exercise can increase the metabolism in an individual to a level as high as 10 times above the resting level (Clark, 2012) and it may strengthen the proposal from Meyer et al. (2011) that individuals may lose as much as 3-8% of their body weight during exercise in a cold environment. Clark (2012), Meyer et al. (2011) and Meyer (2014) all agree on the importance of being hydrated before starting exercise in low temperature to prevent dehydration. Clark (2012) strengthens this by referring to a study conducted among skiers and soccer players where skiers reportedly had the highest rate of chronic dehydration. The study revealed that 11 out of 12 alpine skiers were classified as dehydrated before a competition. In the modern world of sport there is no lack of literature on nutritional needs and exercise (e.g. Robergs and Roberts, 1996; Draper and Marshall, 2014) and the importance of a healthy diet with the right amount of macronutrients and micronutrients for athletes is not being questioned. However, studies investigating nutrition matters in winter sports performed in low temperatures and/or high altitude is, in comparison, very limited. Meyer et al. (2011) looks at how winter sport athletes’ nutritional needs differ with which sport they compete in. The energy requirements for different winter sports is, as for summer sports, diverse and varies from sport to sport. Ski jumpers are perceived as the athletes with the lowest energy requirements on a day to day basis during training and competition with an average intake of between 1600-2000 kcal, whereas cross-country skiers and biathletes have the highest with an average intake between 3000-6000 kcal (Meyer et al., 2011; Burke, 2005). Meyer et al. presents the formula from Sjodin, Andersson, Hogberg and Westerterp (1994) which suggests carbohydrate intake for Nordic sports such as cross-country skiing, biathlon and Nordic combined should be ≥ 6 g ⋅ kg -1 ⋅ day -1 and that the carbohydrate intake for these sports may need to exceed 10 g ⋅ kg -1 ⋅ day -1. The study presents a similar formula for alpine, snowboarding and freestyle as well as well as endurance sports performed on ice (e.g. ice hockey and speed skating) and recommends the carbohydrate intake should not be lower than 6 g ⋅ kg -1 ⋅ day -1 for any endurance sport and the requirement rises when the temperature drops and altitude increases. The study also presents a formula for fat 1.4 – 1.7 g ⋅ kg -1 ⋅ day -1 and protein 1.0 – 1.9 g ⋅ kg -1 ⋅ day -1 (Meyer and Parker-Simmons, 2009). Research on nutrition in winter sports (e.g. Meyer et al., 2011; Meyer 2014; Meyer and Parker-Simmons, 2009; Burke, 2005) indicates that there is a difference between sports in terms of which macronutrients are more important for high performance, but a main perception among current literature seems to be that the main focus for athletes and their coaches should be to maintain energy levels and fluid balance in cold environment and/or high altitude to prevent a drop in performance and/or dehydration.