Concussions are a top concern in the sports world right now, but there’s another medical condition that’s making waves in some crowds. It’s called sickle cell trait. As you might have guessed, it’s related to sickle cell anemia.

People with sickle cell anemia have red blood cells shaped like crescents, or sickles, that tend to break apart, die early and clump together. All this makes for poor blood flow, low red blood cell count and possible organ damage.

Sickle cell trait occurs when a person gets the sickle cell gene from one parent, but not from both. Inheriting two genes causes sickle cell anemia, which is much more common.

People with sickle cell trait normally don’t suffer from symptoms, so they may not even know they have it. But certain situations can bring out its dangerous side. Extreme physical exertion may cause dehydration and low oxygen levels for a person with sickle cell trait. In these cases, blood cells take on the sickle shape, stopping blood flow and causing oxygen depletion throughout the body.

That’s pretty serious. In fact, according to the National Athletic Trainers Association, sickle cell trait is the third most common cause of non-traumatic sports deaths. Only heart conditions and heatstroke top it.

The National Collegiate Athletic Association is concerned enough about sickle cell trait to require screening for anyone who plays Division 1 or 2 sports. Division 3 representatives recently voted to adopt the requirement, too. Athletes with the trait can still compete … and many do so safely … but their coaches and trainers should watch them closely for signs of trouble.

If sickle cell diseases run in your family, talk to your doctor about whether you should be tested for sickle cell trait. It’s better to know and be prepared than to be caught by surprise in a crisis.