Good breathing ways are told in the article, especially when you got cold or fever. But yoga should be done under the guidance of a qualified and experienced person.

Not necessarily. I learned Yoga on my own without the guidance from an instructor. There are several Books and videos are available on line.

http://www.ekhartyoga.com/videos

We have regular camps here and they teaching many healing exercises that are excellent for your lungs and generally for your well being...one of them is breathing exercise , many of which are so very helpful. You realise it after you do it regularly.One of my cousins who used to have attacks of chest congestion is almost fully cured now just doing these exercises regularly .

Very true. Inhalation and exhalation done in a systematic way, that is after inhaling, the exhalation should be very slow. This strengthens the lung power. Incidentally I'm a regular practitioner of breathing exercises. No BP, No sugar. A constant weight for the last one decade.