Exercising affects your breathing, causing you to take deeper breaths, breathe more rapidly and sometimes even gasp for breath. Allergies can add to breathing problems because of the irritation they cause the nasal passages and airways. Put allergies and exercise together, and unusual breathing sounds -- such as crackles -- become more likely.
Your lungs sometimes make unusual sounds as you breathe. Crackling sounds, also called rales, are among the most common, marked by rustling or rattling noises. Some people also compare lung crackling to popping or the noises heard when rubbing two coarse but flexible items against each other, such as two dry sections of hair. The College of Veterinary Medicine and Biomedical Sciences (See Resources) provides audio of lung crackles.
Lung crackles typically occur because of an obstruction. The crackling sound appears when air is allowed to flow through a place that was previously blocked. For example, if fluid in the lungs creates an obstruction but air suddenly passes through, a crackling sound often results. While a range of conditions, including pneumonia, pulmonary edema and bronchitis, can cause these breathing sounds, some people experience them in relation to allergies instead. An allergy can cause increased production of mucus inside the lungs, which leads to a crackling sound while breathing. Individuals with allergy-associated asthma may develop lung crackles as well. In addition, some allergies cause inflammation, which also contributes to lung crackles.
For some people, exercise seems to aggravate lung crackling or make it more noticeable. Often, people choose to exercise outdoors, exposed to pollen and other allergens, which can produce mucus buildup in the lungs and lead to lung crackling sounds. Likewise, exercising often involves breathing air in through the mouth, which can contribute to irritation in the lungs and mucus buildup. Related abnormal breathing sounds may become evident while the person is exercising or right after physical activity. In mild cases, the sounds clear temporarily after the person coughs, but some exercise- and allergy-related lung crackles persist after an exercise session.
A person may experience lung crackles upon inhalation and exhalation. Some people, however, note that crackles become more noticeable when they breathe in rather than upon exhalation. Often, lung crackles become easier to hear when a person exhales or inhales deeply. However, due to the fact that lung crackles can appear because of serious medical conditions, you may benefit from a doctor's evaluation, even if the lung crackles seem exercise-related.