Yesterday I rode to work in -2°F / -19°C temps. When I got to my destination (only about 3.5 miles), my lungs felt terrible. My voice was hoarse and I was coughing a lot. All this despite the fact that I was wearing several wool and fleece layers, a thick balaclava and was completely toasty the whole ride.
The ride may have triggered some exercise induced asthma due to the extreme cold. I tried to cover my face with the balaclava, but there was not enough ventilation and was getting short of breath trying to breath through the fleece, especially when climbing hills.
This sort of thing is something that should not be repeated for the health of my lungs. What gear or techniques can I use to prevent this kind of lung irritation during extreme cold?