Yes.Fatigue is a major issue with COPD. The body uses so much energy when you are active and trying to keep enough oxygen in your system so your body can function, I find that I become tired easily and if I dont take care and overexert myself, I become hypoxic. Hypoxia is a condition caused by low oxygen levels in body tissues.

when i get a out of breath walking i use my puffer and breath through my nose and out of my mouth it helps

Fatigue is a common symptom of COPD, and can be especially difficult if you don't pay attention to what's happening with your breathing, use plb technique to breathe and don't always wear your O2 for things that are difficult and require a lot of exertion. However, fatigue is also a symptom of many other things, so you should discuss this with your doc to be sure there aren't other issues you can take care of.

It can be. But you can also work on your breathing and exercises to help strengthen your lungs and muscles to help. Make sure you keep breathing right and keep O2 on when doing strenuous things.