Cold Weather Comfort and Nutrition Tips

If you cross country ski, alpine ski, bike, hike etc. you have to deal with the cold. For the most part, there is no real risk so long as we take a few precautionary measures. In general, we won’t really be at any great risk until temperatures get below 10° F and skin is exposed (although frostbite is always a concern). Children typically require more protection than adults do and females generally require more protection than males. This is due mainly to differences in muscle mass which directly affects heat production. Being aware of this can help you plan for clothing and nutrition needs on the slopes.

Things to consider include the following:

• The energy requirements are about the same for activities regardless of whether they take place in a warm or cold environment. Furthermore, the heat produced is also about the same provided the work-rate is similar.
• What tends to vary is the amount of clothing and energy substrate usage. People tend to overdress in the cold while exercising leading to increased sweat rates and subsequent chilling due the sweat freezing.
• Pay attention to your environment: Heavy clothing can increase energy expenditure by restricting movement and the energy expenditure for walking on snow is about twice that of walking over a hard surface at the same speed. If it is soft snow, it is even higher.
• Wear your clothing in layers that allow you to easily expose or unzip different parts. That way as you go up and down the mountain you can make slight adjustments to maintain your comfort. Try not to breathe into your clothing as this traps moisture which will eventually freeze.
• Both your clothing and your activity patterns change the way in which you use energy. Most noticeably, they will increase energy expenditure slightly and increase the demand for carbohydrates.

Cold exposure causes vasoconstriction of blood vessels just under the skin. Due to the high fat deposits, this action decreases fat utilization and increases muscle glycogen utilization. Prolonged exercise generally increases the mobilization and oxidation of free fatty acids via the release of epinephrine and norepinephrine into the vascular system. Although cold exposure also triggers a marked elevation in catacholamine secretion, free fatty acid levels increase substantially less than during prolonged exercise in warm weather. Therefore, we have an increased demand for carbohydrates. That is why in just a few hours on the mountain we are starving and craving the good smelling food from the lodge.

Therefore, active replenishment of carbohydrate stores is arguably more important during cold weather exercise or pretty much during the winter. This also has implications for periodic snacking on the hill in between meals, especially for children. The quicker you burn up carbohydrate calories the quicker you will feel fatigued and cold. Children get hungrier more often and fatigue quicker. So for parents, be prepared, as you don’t want a good day spoiled from lack of food preparation. So carry a chocolate bar etc. to provide you with a little energy burst between meals. Then, when you do go inside stock up on breads and fruits and try to include something warm to eat or drink.

Most of this research has been provided to us through the military and they have some advisory guidelines:

1. Drink plenty of water
2. Increase energy intake 25-50% in the form of a well-balanced diet containing a variety of foods but high in carbohydrates.
3. Eat regular meals and consume snacks throughout the day
4. Eat hot, palatable food when possible
5. Moderate coffee and caffeine consumption
6. What would guidelines be without a few Don'ts? Don't drink excessive alcohol when you will be outside in the cold for extended periods of time. It is a myth that alcohol warms you up; in fact, it increases heat loss.

The consumption of alcohol is rather interesting in that it causes the exact opposite effect from common perception. Alcohol causes the blood vessels to dilate thereby causing increased cooling or heat loss. So use the alcohol sparingly and try to avoid it if you are heading back onto the slopes at all.

A final consideration for cold comfort has to do with breathing. Many people get concerned about the cold air ‘freezing their lungs’. The air that enters our lungs is well warmed and humidified by the time it enters our lungs so this is generally not a problem. However, for those that are asthmatic this can present some discomfort in that the cold air can irritate the airways. Always carry the inhaler and if you have severe difficulty try to get indoors out the cold dry air.

For the most part, we have nothing to worry about with sub-zero temperatures so long as we implement a few basic precautions. They include covering exposed skin, carry some snacks, dressing appropriately, which means not too heavy, and practicing vigilance in our food and drink consumption.