Shortness of breath when you work out is often considered to be a good thing. When you work out hard enough to feel a "burn" in your muscles, your body is using sugar as a fuel anaerobically (without oxygen) rather than aerobically (with oxygen). Anaerobic exercise burns about 30 times as much glucose to release the same amount of energy as aerobic exercise, so it's a great sugar detoxifier. It also primes your muscles to take in the sugar and water they need to make the glycogen that "pumps them up" as you recover. For a few minutes of pain, you experience multiple levels of gain. But not every kind shortness of breath when working out is due to anaerobic respiration.
Sometimes shortness of breath when working out is due to exercise-induced asthma. It's not inaccurate to liken exercise-induced asthma to an "exercise allergy." Unlike working out to get the burn, exercise-induced asthma doesn't require maximal effort. It's not something that's usually triggered by weight lifting or running, cycling, or swimming at maximum speed. It's a condition that most commonly occurs in people who have asthma anyway, only exercise triggers the attack, rather than dust, or pollen, fumes, or drafts .
What Are the Symptoms of Exercise-Induced Asthma?
Asthma that is triggered by exercise (which may occur during or shortly after exercise), requiring shortness of breath treatment, produces hallmark symptoms:
- Shortness of breath, coughing, and wheezing.
- Chest tightness, sometimes with painful breathing.
- Stomach upset: Nausea, diarrhea, vomiting, and/or acid reflux.
- Underperformance on the playing field.
- Unusually long recovery time. 
Exercise-induced asthma occurs at cool temperatures and dry conditions. It's more likely when you already have a cold, or there are high pollen counts (even if you aren't otherwise allergic to the kind of pollen causing the high pollen count). Working out hard can trigger an attack, but so can doing aerobic exercise at a moderate pace for 10 minutes or more. 
Teenagers sometimes go to great lengths to disguise exercise-induced asthma so they won't disappoint their teams . And this kind of asthma is sometimes misidentified as simple fatigue.
How Can You Tell the Difference Between Exercise-Induced Asthma and Simple Fatigue?
Exercise-induced asthma isn't something you can fake, at least not when a trainer or a doctor has a pulsOx meter (finger meter) handy. All the trainer has to do is to measure O2 levels. If they are low, it may be asthma. If they aren't going down, it probably isn't asthma. Instead, it could be simple fatigue. Less likely, it could be a spasm of the larynx. (In a hospital setting, the pulmonologist would look for increasing CO2 levels in exercise-induced asthma). 
How Can You Tell the Difference Between Exercise-Induced Asthma and Hyperventilation?
Shortness of breath when working out often is a psychological issue. Sometimes athletes breathe uncontrollably hard and fast because they are anxious. When the speed of respiration is altered because of "nerves," the amount of air breathed in changes to that O2 levels stay more or less constant. If a child or a teen on the playing field is hyperventilating, but O2 levels are 95 percent or above, they probably don't have exercise-induced asthma .
And exercise-induced asthma occurs during or after exercise, not before it .
Exercise-Induced Asthma Is Manageable
Even elite athletes can experience exercise-induced asthma. About 10 percent of the people who experience the condition don't have any other health problems . Just about anyone who has exercise-induced asthma can take measures to reduce the frequency and severity of attacks.
What are some natural ways to manage dyspnea in exercise-induced asthma?
- Stay hydrated, even in cool weather. Drink water even if you aren't sweating. The osmolar hypothesis of exercise-induced asthma holds that fluid levels in the lungs fall so that concentrations of certain electrolytes rise. They get so high that they trigger the release of histamine, just as in an allergy.  Staying hydrated helps you breathe more easily while you are exercising.
- Breathe through your nose, not through your mouth. Your nasal passages warm air before it reaches your throat. The rewarming hypothesis explains exercise-induced asthma as a phenomenon that occurs the blood vessels in the bronchial passages expand after a workout. While you are working out, these blood vessels constrict to conserve heat. When you stop exercising, you aren't inhaling as much cold air, so they expand, filling up the bronchi. [9,10]
These rules help prevent exercise-induced asthma in every sports except one, swimming. Swimming in a warm, non-chlorinated water is a helpful exercise for asthma. Swimming in chlorinated water tends to make it worse, and the more contact with chlorine you get, the more problems with asthma you will have . Exposure to chlorine before the age of seven has a cumulative, detrimental effect on asthma in children that becomes a tendency to exercise-induced asthma later in life, so find bacteria-free settings for budding preschool athletes for their maximum performance later.