How often do you pay attention to your breathing? For some people, breathing isn't always easy. Out of every 10 kids, 1 to 2 suffer from asthma. During an asthma flare-up, airways swell and narrow, trapping air. Kids may feel as if they are trying to breathe through a straw. Doctors use lung function tests to monitor people with asthma and find out how much air they can inhale and exhale.