Last year one of the things I wanted to work on was breathing. I thought I had an iron deficiency because I was short of breath, but it was really food allergies. Still, when I had my lung capacity tested it was pretty bad. The medical doctor told me to exercise, but at the time I was too weak to do any strenuous physical activity. So I went in search of a gentle solution.
Dr. Weil has three breathing exercises on his blog that I find helpful. The first one is really simple and sometimes I do it when I wake up in the morning. All you need is fifteen seconds.