December is upon us and with that comes snow and winter weather, well actually that’s been since October here! To allow the rest of you to bask in the fall warmth for a little longer though; we’ve been holding off on this post until the time seemed right. We think EVERYONE is now ready for winter. Staying active in the cold and dark can be a bit more challenging, BUT there are a ton of great winter sports and we encourage you to try them all. To help motivate everyone to get out there, be active, and stay healthy we are posting on Nutrition for Winter Sports.
There are several nutritional challenges for athletes competing in winter sports. These athletes are often exposed to environmental extremes that can increase energy expenditure and the rate at which the body uses up its glycogen stores (glucose or energy). The cold dry air also increases fluid losses, a fact that often goes unnoticed as athletes tend to drink less in the cold. In addition to the cold, many winter sports also occur at higher altitudes presenting an additional challenge (1). We’ll discuss nutritional challenges for those competing in the cold weather this week and continue on with the effects of altitude next week.
How is Exercising the Cold Different?
Exercising in cold weather can increase the amount of energy needed. If protective clothing and physiological responses such as constricting the blood vessels and heat production due to increased movement can maintain body temperatures, energy needs may not be significantly higher. Conversely, if additional energy is needed to maintain body temperature, especially if shivering is involved, then energy needs during cold weather exercise can increase greatly (2). It is important to keep in mind not just the temperature but the wind chill (Calgary anyone?) and humidity. All of these factors are important in the body’s ability to maintain its core temperature (3). Hydration is also a concern for cold weather athletes. There can still be large fluid losses due to sweat, as well as respiratory water loss because of the low humidity, cold-induced diuresis, and limited access to fluids (1).
It has been suggested that athletes training and competing in the cold require more calories that those competing and training in warmer weather (1). Looking at the individual sports; cross-country skiers have been reported as having the highest energy expenditures due to the endurance nature of the sport as well as their larger muscle mass (as compared to say runners or ski jumpers) (4). These athletes need to consume very high energy intakes and should monitor their body weight to ensure they are meeting their energy needs.
Carbohydrates, Proteins, and Fats
For the endurance winter sports glycogen stores are often the limiting factor and carbohydrate intakes should be between 6 and 10 g/kg body weight/day (5). When exercise lasts longer than one to two hours athletes should ensure that they are consuming some carbohydrate during exercise either through a sport drink or easily digestible foods and water. The goal is 30-60 grams of carbohydrate per hour and in some cases up to 90 grams per hour (1). Make sure you take your carbohydrates with some fluid as well.
Alpine skiers and other power athletes can have increased lactate concentrations and muscle glycogen depletion and should consume carbohydrates while training on snow (6). Protein should be 1.4 to 1.7 g/kg body weight/day and most athletes meet this requirement (7). Fat should be 25 to 40% of total energy or 1 to 1.9 g/kg body weight/day (8). Choose healthy fats including plant oils, nuts, seeds, and fatty fish. Fat intakes may need to be higher in winter athletes, as they require more energy dense foods to meet their increased energy needs.
Consuming adequate fluids during winter exercise can be extremely challenging. I cannot count the number of times my water bottle has frozen during a long ski! The best advice is to use the amount of sweat and check for signs of dehydration (headaches, fatigue etc.) to determine fluid needs. To quickly figure out how much water you need you can weigh yourself before and after your work out (without clothes). If you’ve lost more than 2% of your body weight then you need to increase your intakes next go around. When you do so be sure to make small adjustments for the exercise time, intensity, and temperature changes. Tip: Try starting with warm water and adding a sport or electrolyte mix to your water to delay the freezing a bit. There are also insulated water bottles and containers with larger lids.
The body is not able to produce vitamin D effectively in the fall and winter months so it is advisable for everyone to take a vitamin D supplement of 1000 IU. This is especially important for athletes, as vitamin D is required to maintain a healthy immune system. For athletes it also seems that consuming vitamin C daily can reduce the risk of upper respiratory tract infections. The doses used in the studies vary but a minimum of 200 mg and a maximum of 1 gram appear to have some benefits without side-effects (9).
Nutrient timing is similar to summer sports, however, be sure to adjust for increased fluid and energy intakes if necessary. Ideally you want to eat a pre-workout meal and a pre-workout snack that are high in carbohydrates, give you a little bit of protein, and are low in fat and fibre. If your event is longer than an hour or so try to consume some carbohydrate, fluid, and electrolyte during the event or training. For longer races (i.e ~ 30 km or over 2 -3 hours) carbohydrate loading may be beneficial (1). Nutrient timing can also be challenging for winter athletes as environmental conditions may result in delayed competition times. If this is the case, you’ll have to adjust on the fly. Recovery is the same as warmer weather. Eat high glycemic index carbohydrates, proteins, fluids, and electrolytes within the first 30 minutes of completing the workout (1).
- Meyer NL et al. (2011) Nutrition for winter sports. Journal of Sports Sciences. 29;sup1, S127-136.
- Castellani JW et al. (2006) American College of Sports Medicine position stand: Prevention of cold injuries during exercise. Medicine and Science in Sports and Exercise. 38:2012-2029.
- Sawka MN et al. (2000) Blood volume: Importance and adaptations to exercise training, environmental stresses, and trauma/sickness. Medicine and Science in Sports and Exercise. 32:332-348.
- Ekblom B et al. (2000). Cross-country skiing. In R.J. Maughan (Ed), Nutrition in sport (Vol. 7 pp 656-662): Oxford: Blackwell Science.
- Sjodin, AM et al. (1994) Energy balance in cross-country skiers: A study using doubly labeled water. Medicine and Science in Sports and Exercise. 26:720-724.
- Ferguson, RA (2010) Limitations to performance during alpine skiing. Experimental Physiology. 95:404-410.
- Phillips SM et al. (2011) Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci 29 suppl 1:S29-38.
- Meyer NL et al. (2009) Winter sports. In L. M. Burke (Ed), Practical sports nutrition pp. 335-358. Champaign, IL: Human Kinetics.
- Heimer KA (2009) Examining the evidence for the use of vitamin c in the prophylaxis and treatment of the common cold. J Am Acad Nurse Pract 21(5):295-300.