What are four conditions and activities that can affect the outcome of a spirometer test?

Several conditions and activities can impact the outcome of a spirometer test. First, recent respiratory infections or illnesses can lead to temporary changes in lung function. Second, smoking before the test can impair lung capacity and airflow measurements. Third, strenuous exercise immediately prior to testing may affect baseline lung function, and fourth, anxiety or improper test technique can lead to inaccurate results.