Shortness of breath is the sensation that you can't get enough air into your lungs. It might indicate an underlying health condition. The sensation might be worse while you are physically active or when you rest down. Other symptoms might include a cough or fever. If you are having any of these issues, see a breath-testing doctor (https://newyorkcardiac.com/shortness-of-breath-dyspnea). If your shortness of breath is sudden or severe, or if you are also experiencing chest symptoms, contact 911. Symptoms Shortness of breath makes you feel as if you can't get enough air. You don't feel like you're getting enough oxygen into your lungs or breathing deeply. You may also notice a tightness in your chest. Causes Shortness of breath can be caused by several factors, including: - Asthma; - Other lung illnesses (including emphysema, which is primarily caused by smoking); - Heart failure; - Panic attacks; - Allergies. If you are experiencing shortness of breath, coughing, and/or fever, you may have a chest infection or pneumonia. Less common causes of breathing difficulty include lung cancer, blood clots in the lungs, air leaks around the lungs, and scarring of the lung tissue. Diagnosis Your doctor can assist you in determining the root cause of your breathing difficulty. They will start by asking you questions about your symptoms and doing a physical examination. Your doctor may also prescribe certain tests. To determine the reason for your shortness of breath, your doctor may conduct a chest X-ray. They will also measure your body's oxygen saturation by inserting an oximeter on your finger. They may also request an electrocardiogram (ECG). During this test, your doctor will have you lie down to monitor your heart. The ECG equipment makes an image, or tracing, of your heart's electrical impulses. You may require a computed tomography (CT) scan, which is a sort of X-ray. Your doctor may use a spirometer to test the intensity of your breathing and the amount of oxygen in your blood. You may also need a blood test or a specialist lung test known as a pulmonary function test (PFT). Can Shortness of Breath Be Reduced or Avoided? The ability to avoid shortness of breath is determined by the underlying cause. If it is caused by allergies, you may be able to avoid it by determining your allergy trigger. Once you know what causes your allergies, you may try to avoid it. If your shortness of breath is caused by smoking, quitting can help to prevent it. Other factors may not be as easily avoided. Inhalers can assist if the problem is caused by a medical condition like asthma. Treatment Your doctor will address the source of your breathing difficulty. If you smoke, you must quit in order to benefit from therapy. Ask your doctor for assistance. Also, avoid inhaling substances that might irritate your lungs, such as paint fumes and automobile exhaust. If your doctor thinks it's acceptable, you should aim to get more exercise. Living With Shortness of Breath It might be frightening to experience regular shortness of breath. It can become less frightening if you learn to regulate it. Work with your doctor to develop a personalized control strategy. Your doctor may recommend medicine, an exercise regimen, breathing methods, or a mix of the above. In some circumstances, they may suggest supplementary oxygen. Questions to Ask Your Doctor - What is the most likely reason for my shortness of breath? - Do I need any tests to discover the source of my shortness of breath? - Is shortness of breath indicative of a more serious problem? - Is it safe to exercise? What type of workout may I do? - Based on the reason for my shortness of breath, what is the best treatment option? - What lifestyle modifications can I do at home to assist in alleviating my symptoms?

With a pandemic raging, I hear a lot about testing. One problem is we don't have an adequate supply of test kits to screen for Covid-19. But another problem would arise even if we had enough kits to test everyone. To explain, I'll describe an example presented in Chance in Biology: Using Probability to Explore Nature, by Mark Denny and Steven Gaines. Their analysis was based on testing for HIV, but I'll recast the story in terms of the coronavirus. Suppose we have an accurate test for Covid-19. No test is perfect, so let's assume it's correct 99.5% of the time. In other words, its error rate is 0.5% (one error for every two hundred tests). Assume this error rate is the same for false positives and false negatives. Furthermore, assume Covid-19 is not prevalent, infecting only 0.1% of the population. I doubt this is a good assumption right now, when the virus seems to be infecting everyone, but I can imagine a time not too far in the future (a few weeks maybe, a few months probably) when the fraction of people having the virus is small. In a population of a million people, 1000 would have Covid-19 and 999,000 would not. First, consider what happens when you test the thousand that are infected. The test would come back positive for Covid-19 in 99.5% of the cases, so it would produce 995 true positives. The test would be in error and give a negative result 0.5% of the time, giving 5 false negatives (the test would say you don't have the disease when in fact you do). Next, consider the results from testing the 999,000 people who are not infected. Again, the test accuracy is 99.5%, so you would get a negative result (true negatives) for 994,005 people (0.995 times 999,000). You'd make a mistake 0.5% of the time, so you get false positives in 4995 cases (the test would say you have the disease when in fact you don't). Let's summarize: True Positives 995 False Positives 4,995 True Negatives 994,005 False Negatives 5 Now, suppose Michigan Governor Gretchen Whitmer (I'm a big fan of the governor) decides that—to prevent the virus from flaring up again—everyone will be tested; anyone who tests positive for Covid-19 must be quarantined, and anyone who tests negative is free to go wherever they please (restaurants, sporting events, movies... oh how I miss them!). Out of a million people, 5990 will test positive (995 + 4995). Of those, 4995 are mistakes (false positives). In other words, 83% of the people who are forced into quarantine are false positives; they don't have the disease, but the blasted test said they do and they must suffer for it. Only 17% of the quarantined people are infected. Is this acceptable? Maybe. We might decide as a state that it's worth it; we insist on quarantines, even if five out of six people forced into isolation are actually healthy. The needs of the many outweigh the needs of the few. Or, we might decide this is too high a price to pay; people are innocent until proven guilty, so to speak. This decision is not simple. Whitmer will have people mad at her regardless of what she does. But we must decide based on the facts. If the incidence of Covid-19 is 0.1%, and the accuracy of the test is 99.5%, then five out of six quarantined people will be false positives. That's how the math works. Denny and Gaines summarize it this way: “Although individual tests have a low chance of error, most individuals who are tested are not infected with [Covid-19]. Therefore, we are multiplying a small probability of false positives by a large number of uninfected individuals. Even a minute probability of false positives for individual tests can in this circumstance produce many more false positives than true positives. As long as the disease is rare, even a very accurate test of infection will not be able to accurately identify infected individuals in a random test.” I don't know the prevalence of Covid-19 or the accuracy of Covid-19 tests. The numbers for the coronavirus may be different than what I used in this example. My point is that even an accurate test can produce many false positives for a rare disease. That's an important insight, whether or not the numbers are accurate for our current plague. Chance in Biology is full of examples like this one. It's a good book (although I like Denny's Air and Water better). It's a useful supplement to Intermediate Physics for Medicine and Biology, providing all the probability you need to understand biological physics. Originally published on April 13, 2020 at https://hobbieroth.blogspot.com/2020/04/a-problem-with-testing.html