Oxygen inhalation for 3 hours is effective, but is recommended for more than 15 hours per day, with low-flow oxygen of 1-3 L/min.
In general, if the emphysema only wheeze when walking fast, without other obvious symptoms manifestation, then 3~4 hours of oxygen inhalation per day has some effect.
However, people with emphysema who wheeze when they move need longer oxygen intake. It is recommended to use low-flow oxygen for more than 15 hours a day, 1~3L/min. 3 hours of oxygen per day will not relieve the symptoms completely. Whether it is effective or not depends on the results of the examination, including lung function, lung X-ray examination, etc.
It is recommended to seek medical advice in a timely manner.