Hello doctor,at 4 months of non smoking i want to know how my lungs is improved since i quit after having smoke half a pack a day for 4 years.thanks?

Exercise tolerance: Hi. If your breathing is better, you can exert yourself, you don't have cough or phlegm coming up, likely your lungs are healthy and will continue to be so as long as you don't restart smoking. You can also get a pulmonary function test if you have any symptoms. In the absence of symptoms, your young age and relatively limited smoking, the pulmonary function tests are highly likely to be normal.