Yes, we all do use more oxygen when we use our muscles . I go from 3 to 4ltrs. . I sleep with 3. Turn it up during the day , as I don’t sit still much . I am on 24/7 oxygen . Turning your machine up is not so simple with a portable. The most important thing is to use an oximeter. Use it often and be sure you stay above 90% saturation. I was taught to keep it handy and use it often. I was diagnosed with stage 4 Emphysema almost two years ago. I have not had an exasperation . My pulmonologist asked me , how long since I had a cold or the like . It was the fall of 2021. I wear a mask if I go out in public . I pull a cart with an oxygen tank on it . Portable concentrators will not deliver over 3 ltrs. The dial on them is misleading. Keep your oxygen over 90%. It will help you feel better and live longer . I do not care about people ‘s interest or stare. I just do what I need to feel good . Best to all of you . Crystalena (the one with the tank)