When you drink cold fluids, your body expends energy to heat them to body temperature. Many cyclists riding in winter actually have higher caloric needs than during warmer weather. Contributing are adverse conditions caused by the increased weight of clothing, heavier equipment, and stronger winds. The added weight of winter clothing alone can cause a marked increase in oxygen consumption.
As the saying goes, there are three times when you should drink on a winter ride: when you are thirsty, when you are not thirsty, and in between. Becoming dehydrated during winter not only will hinder performance, but it can make it harder to maintain proper body temperature.
Of course, it can be difficult to prevent fluids from freezing. Two solutions: Wear a CamelBak hydration
system under your jacket or place your bottles close to your body. Using energy drinks containing carbohydrate and electrolytes will lower the freezing temperature several degrees and assist with caloric replacement. When off the bike, avoid drinks containing caffeine or alcohol as they contribute to dehydration by increasing urination. Alcohol also speeds heat loss through dilitation of the superficial blood vessels.
Some athletes experience a condition known as exercise-induced asthma. This causes the bronchial passages in the lungs to constrict during hard exercise. Cold, dry air can precipitate an attack. Covering the mouth with a scarf, balaclava or ski mask can help warm incoming air.
Never go on a winter ride without carrying sports bars, gels or some other form of high-energy food. Even if you don’t intend to ride long enough to need anything but a sports drink (about 90 minutes or less), you could be out longer than expected due to change of plans or a mechanical breakdown. Bonking on a freezing day isn’t just unpleasant, it can be dangerous. Like with fluids, carry your food inside your jacket so it doesn’t freeze.