I'm a lifelong asthmatic from Australia. I listened this morning (07/12/08) to a radio interview with Dr Mike Thomas on ABC Radio National's Health Report (you can listen to it here, or read the transcript: abc.net.au/rn/healthreport/... ).
When I was a child in the 1960s my grandfather (also a lifelong asthmatic) taught me how to do diaphragm breathing and I have breathed this way ever since. I have always found it to be helpful, especially when symptoms are persistent, or if I've been caught out without a 'puffer' at the onset of an attack. Diaphragm breathing has been enough to keep the attack from worsening until I can reach my reliever medication. My dear old granddad also recommended ginger to help with symptoms. This is in the decades before preventer and reliever medications were available.
I often think that asthma is a condition where one can not-so-much breathe as exhale, which therefore results in the lungs remaining full of air, making further intake of air impossible. At least that's how it feels for me. Regards, Kate