I'm asthmatic also. It was severe as a child, outgrew it for 50 years or so, and has come back in the last 10 years. It is well under control with a Symbicort inhaler but colder weather increases symptoms. But I'm still interested in the mechanics of breathing as I've learned from hiking in mountainous terrain that good mechanics can improve performance. A recent article in Velo News had good info on how exercise can improve oxygen up take. http://velonews.competitor.com/2013/...he-bike_306454 What drew my attention was muscle imbalances that effect breathing and oxygen uptake. That outlook fits in with what I've been learning recently about the mechanics of breathing.

Basically, while the diaphram is the primary muscle for breathing, the process is aided by the intercostal muscles spanning the rib cage. These muscles help open the chest on inhaling and to close the chest to exhale. The entire rib cage is crisscrossed with oblique bands of muscle, inside and out, that move the ribs to expand or contract. A simple experiment illustrates the effect. If you drop the chin and hunch the spine a bit and then inhale, air moves slowly and with difficulty into the chest. When you raise the chin and straighten the back, you can feel the chest opening up and air easily rushing in. The link shows what muscles to work on. Also I found a book "Yoga Anatomy" from Human Kinetics the clearly shows the mechanics of breathing and the muscles involved. http://www.amazon.com/Yoga-Anatomy-2...s=Yoga+Anatomy While VO2 max capacity is mostly genetic, it is clear oxygen uptake can be improved, even if only slightly, by strengthening those muscles involved in expanding the rib cage.

We are familiar with the athlete who after a hard effort is bent over double, hands on knees, trying to catch their breadth. This is a position I knew well as a child as it was the only position during an asthmatic attack I was able to sleep in. This bent over position is the one we typically see on a road bike. It gets weight over the pedals but also opens the chest for better breathing. Furthermore, a straight back helps maintain the chest cavity in the best position for both inhaling and exhaling. There is still a bit more to this breathing business so I can't recommend Yoga Anatomy enough, especially for asthmatics.