For COPD, I wanted to mention a couple of other possibly useful aids: one is serrapeptase, which is a supplement that dissolves fibrotic lesions in the body. Some folks with copd'ers are breathing more easily since using that. Be careful if you tend to bleed easily, though, or are taking a blood thinner.
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.