★★★★★
The other idea is to find a breathing technique that works for you. Life Lift and Bodyflex are two funny-looking ones that can help a lot. Fine for most people, unless you have high blood pressure or glaucoma, (or are pregnant, which I'm thinking doesn't apply to you). I've seen a demo of the bodyflex breath on youtube before. The life lift version is slower and gentler (the bodyflex founder learned it from the life lift lady, actually. )
Basically, you gently blow all the air out of your lungs through your mouth, as if blowing through a tube... A martial arts article explained that there are multiple benefits to doing it this way, btw... Then a big inhale through the nose (smile to open up your nostrils to their widest), hold a second or three, then blast the air out, and pop your lips as you say "Paaaaaaaah. " It isn't vocalized, it's just air. Then you hold your breath and suck in your gut as if rolling up your abs. In fact, there is a yoga move like this. Hold your breath. With practice, you will feel the suction as you do it, and when you release the air and hear a sucky sound. Hold as long as you feel comfortable holding your breath, but you don't need to go longer than a count of eight or so, and repeat. Fifteen minutes a day should dramatically help oxygenation and lung flexibility. If you have contraindications for that sort of breathing, then incorporating any gentler, intentional breathing exercises into your day should be a must on your daily to-do list.