To prepare for your test, you should avoid smoking for 24 hours and refrain from eating a heavy meal for at least 2 hours before your appointment. Wear loose, comfortable clothing that doesn’t restrict your chest or abdomen. We’ll provide specific instructions regarding your inhalers; typically, you’ll stop short-acting bronchodilators 4 to 6 hours before the test. Following these steps ensures your results are a true reflection of your baseline respiratory function.