I've been developing this problem from over a year now. I have low saturation of oxygen (73-88%) especially at night. I have to use oxygen while I sleep. I also get very tired when I move even if it's not at all a straining effort. I can't walk or go outside anymore because my muscles can't take it and I get dizzy, with my ears plugged and a headache. I'm short of breath even to speak too fast or hold my breath to wash my face. You must know I'm overweight and I smoked a lot for the past 13 years, although I'm trying to quit. Nobody where I live can tell me what's wrong, please help me.