About Winter Sports
The winter sports that are part of the Olympic Winter Games include biathlon, bobsleigh, curling, ice hockey, luge, skating, skeleton and skiing. Within skiing, there are five disciplines and these include alpine, cross-country, ski jumping, Nordic combined, freestyle and snowboarding.
This fact sheet will provide a background on the nutritional implications for skiing, specifically, the effect of altitude and cold exposure as these are unique aspects to these sports. The winter competition for skiing starts at the end of October and concludes in late March. Olympic Games and World Championship are held during the month of February and occur in three out of the four-year cycle. The off-season is held during the month of April. Each athlete competes in approximately 30 to 45 events over a five-month winter season.
Nordic combined and ski jumping benefit from a low body weight and high level of anaerobic power with Nordic combined athletes typically at least 5kg and ski jumpers 10kg below their ideal body weight. Computer simulation shows that the jump length decreases by approximately 1m/kg of increased weight. There is a tendency for very young athletes to compete in international competitions because they generally weigh less than their older athletes of similar height. Delayed growth and maturation has also been observed in ski jumpers as well as extreme weight loss and eating disorder cases.
The physical structure of cross-country skiers has changed over the last twenty years with them now reported as muscular and having average height. Cross-country skiing is an endurance sport requiring a high aerobic and anaerobic capacity. Cross-country skiers have the highest VO2 max of all endurance athletes.
Successful alpine skiers appear tall and heavy with a high lean tissue mass. In general, slalom skiers tend to be lighter and leaner than speed skiers in events such as downhill and “super-G”.
As many aerialists have a gymnastics background, physique characteristics are similar to gymnasts, particularly female athletes, although aerialists appear older and heavier. Energy metabolism in freestyle skiing for both events is expected to receive a large contribution via anaerobic energy pathways due to their high intensity and short duration. Energy for the aerialist is predominantly anaerobic due to the short duration of a jump (6 to 7 seconds), while the mogul skier relies, to a greater extent on muscle glycogen.
The most important nutritional factors to consider when working with winter sport athletes are the effects of cold and altitude that may lead to increased energy expenditure, greater reliance on blood glucose and muscle glycogen, and increase fluid loss. Upon ascent to altitude, hormonal changes occur which leads to an increase in ventilation, vasoconstriction, as well as blood and vascular pressure.
Altitude exposure is frequently accompanied by weight loss that is often associated with negative energy balance due to appetite suppression and increased energy expenditure. Exercise in the cold may increase energy requirements, with 10 to 15% of the rise in energy expenditure due to the movements associated with exercising in heavy snow and thermoregulation.
It has previously been demonstrated that fuel selection at high altitude shifts to a greater use of blood glucose for men both at rest and during exercise compared to sea level. It has also been shown that carbohydrate oxidation may be elevated up to six-fold during shivering thermogenesis. This rise in carbohydrate oxidation is provided by greater plasma glucose turnover, muscle glycolysis, as well as glycogenolysis.
Living and training at altitude increases the athletes need for adequate iron stores in order for haematological adaptations to occur. Although well managed today, iron deficiency and depletion remain the most prevalent nutritional deficiency in winter sports.
Fluid requirements are higher in the cold compared to temperate environments, as cold air contains less water than warmer air, even if relative humidity is the same. Thus, cold exposure leads to a small but significant increase in respiratory water loss. In addition, cold temperatures can result in an impaired thirst response as well as an increased need to urinate.
Hydration can sometimes be as impractical as undesirable, due to restricted access to fluids, coupled with a reluctance to drink in the cold, or fear of the need to urinate (as toilets may be inaccessible!). While individual fluid recommendations during exercise vary, good fluid choices include flavoured milk, juice, hot chocolate/Milo, soup, or meal replacement shakes like Sustagen® Sport for long sessions on the snow. Sports drinks can encourage fluid intake and can assist with fluid retention, reducing the need to urinate while on snow. They also provide carbohydrate to help meet fuel needs.
Fluid intake is usually reduced when fluids are very cold (or frozen). Cool fluids (10 to 15oC) are generally preferred during strenuous sessions but in very cold conditions, warmer fluids may be more inviting. Try packing a thermos or insulated drink containers to prevent the temperature dropping to very low levels.
Eating and drinking during competition
For cross country events longer than 15kms, sport drinks should be provided to the athletes. Transporting large volumes of fluid onto the ski course and keeping the temperature of the beverages at 10 to 20°C is challenging. It is recommended that warm sports drinks be carried in leak-proof containers that have thermal covers.
For the other skiing events, fluid is provided at the end of the first and final run or jump. Carbohydrate-rich snack foods should be available to athletes to have between runs or jumps such as fruit, cereal bars, sports gels, sports bars, fruit muffins, jam sandwiches, hot chocolate, soup.
One thing to remember when packing snacks and drinks is that liquids freeze and bars get hard to chew! So, pack a thermos with warm liquids and place a heat pack around bars, lollies and gels. Socks can be handy to keep bars in, too! Thermal bowls are also available and will keep hot meals hot is sealed well. If training, you can also keep these foods packed into pockets and jumpers so that your own body heat keeps these foods edible.
Glycogen (carbohydrate) stores can be significantly reduced after a typical day of training or competition. Because of this, recovery of these stores should start as soon as possible after prolonged and/or high-intensity training and racing. A delay in returning to accommodation after training, may slow recovery time and affect the next day’s training so it is important to have portable snacks and meals handy to kick start recovery such as:
- Warm soup + bread rolls
- Pasta with tomato meat based sauce (can be kept warm in thermal bowls/containers)
- Meat and vegetable stir fry with rice
- Porridge made with milk