FEV₁ - between 30 and 50 percent of normal predicted. You are often tired and short of breath and may have frequent exacerbations requiring extra treatment or even hospitalization.

Stage IV: Very Severe (sometimes called end-stage) COPD

FEV₁ - less than 30 percent of normal predicted. You may often be short of breath, even at rest.

It is important to know that one person's numbers don't mean exactly the same thing for another. We're all different.

If that's the case, why should you know your numbers? Well, it is always good idea to know what you're dealing with.

3.) Don't Give Up!

Before you phone your local monument company to have them carve today's date on your gravestone, know that with proper care and treatment you can live for years with very limited lung function! The term "end-stage" is just a term, based on the perspective of who you're talking to. For example, a respiratory therapist who works with severe but stable COPD patients in pulmonary rehabilitation has a different take on your prognosis than a doctor or a nurse who sees patients only when they are sick. In doing research for this post, I read an article written by a home care nurse who talked about patients with less than 30% lung function as being end stage and barely able to walk more than a couple of steps. I'm here to tell you that there are many patients in our program with less than 25% lung function who do very well! So, no, being told you have "end-stage COPD" is not a death sentence. There is a lot you can do, and you can live a long time.

Watch for my next post when we'll talk about where you can go for help and what you can do to stay healthy and how to make the most of day-to-day life with severe (end-stage) COPD.

Jane M. Martin is a licensed respiratory therapist and teacher, the founder and director of http://www.Breathingbetterlivingwell.com and author of Breathe Better, Live in Wellness.