Chapter 2 in every one of my books is dedicated to realxation and breathing. After my heart surgery to years ago, I was intoduced to the "incentive spirometer".
http://respiratory.healthcaresupplypros.com/dhd222500h $13 I'll post a picture of one in the gallery "Enhancements"
An incentive spirometer is a medical device used to help patients improve the functioning of their lungs. It is provided to patients who have had any surgery that might jeopardize respiratory function, particularly surgery to the lungs themselves,[1] but also commonly to patients recovering from cardiac or other surgery involving extended time under anesthesia and prolonged in-bed recovery. The incentive spirometer is also issued to patients recovering from rib damage to help minimize the chance of fluid build-up in the lungs. It can be used as well by wind instrument players, who want to improve their air flow.
The patient breathes in from the device as slowly and as deeply as possible, then holds his/her breath for 2-6 seconds. This provides back pressure which pops open alveoli. It is the same maneuver as in yawning. An indicator provides a gauge of how well the patient's lung or lungs are functioning, by indicating sustained inhalation vacuum. The patient is generally asked to do many repetitions a day while measuring his or her progress by way of the gauge.
The breathing technique is the same used in "Psychoprophylaxis" (AKA in the US as the "Lamaze" method). This technique is what Dr. Hironori Higuchi used as his "Sport Blowgun Health Method" over a decade ago when he first published about using competitive blowgun shooting as a way to super-oxygenate the blood for recovering para and quadra-palegics and for seniors. If you watch a video about blowgun shooting in Japan - they almost always fo this technique prior to shooting. The raising of their arms above their heads helps expand the ribcage, allowing more complete airflow.
You wil even see David Caradine, Chuck Norris and Bruce Lee doing similar breathing exercises n their videos.