Exercise in cold ambient air produces significant physiologic and psychological challenges. The physiologic strain of exercise in cold weather depends on three factors: a) hydration level, b) body metabolism, and c) body fat. One of the functions of the upper airways is to warm and moisturize the inhaled air before reaching the bronchi.
Cold air does not usually damage the airways. Even in an extreme cold weather, the inhaled air usually warms to 27 - 32°C by the time it reaches the bronchi. When exercising in cold weather, you breathe large volume of cold, dry air. The respiratory passages have to warm and moisturize the air you inhale, which results in considerable loss of water and heat. Water loss from airways usually contributes to overall dehydration, dry mouth, burning sensation in the throat and irritation of the airways.
Cold-induced dry throat usually triggers cough during the recovery period. In people with asthma, the signs and symptoms may exacerbate (cold weather-induced asthma attack). Studies have confirmed that post-exercise coughing in cold weather relates directly to the overall respiratory water loss, not heat loss.
Another interesting fact is that the body shows remarkable flexibility in selecting fuel when exposed to cold. A response to cold is shivering, which serves an important role in maintaining core body temperature.