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What is it?
Sickle cell trait affects millions of people worldwide. Sickle cell trait is seen in all races in the US, although it is found most commonly in African-Americans, affecting 5-8% of that population. Sickle cell trait is an inherited blood disorder in which “hemoglobin,” the part of the blood that colors it red and is responsible for carrying oxygen, does not have a normal molecular appearance. This is turn leads to the normally disc-shaped red blood cells in which hemoglobin is found to appear like “sickles” instead, thus the name of the condition. Unlike sickle cell disease, in which patients have two genes that cause the production of abnormal hemoglobin, individuals with sickle cell trait carry only one defective gene. People with just the “trait” and not the “disease” typically live normal lives without health problems related to sickle cell. Under extreme conditions such as high altitude, severe dehydration, high temperatures, or highly intense physical activity, however, red blood cells can become really deformed or sickle-shaped, which may lead to complications related to these sickle-shaped cells not being able to move freely within the body. In rare cases, death can even occur.

Complications from sickle cell trait are rare. A common presentation is that of “conscious collapse,” where an athlete complains of severe leg pain, cramping, and inability to move the legs despite remaining conscious and alert. Other symptoms may include:

  • Muscle cramping/pain
  • Abdominal pain
  • Changes in vision or increased pressure in the eye
  • Difficulty breathing/shortness of breath

Sports Medicine Evaluation and Treatment
Sickle cell trait is genetic and more likely to be present if family members also have the disease. All newborns in the United States are screened for sickle cell disease. The National Collegiate Athletic Association (NCAA) also currently requires screening prior to participation in athletics. A simple blood test is sufficient for diagnosis.

Any athlete with an observed conscious collapse needs to be transferred to the emergency room immediately. Athletes with sickle cell trait who have complications associated with sickle cell trait require careful evaluation by a sports medicine physician.

Injury Prevention
There is no routine impediment for participation in athletics or exercise based on having sickle cell trait. Keys to decreasing the risks associated with this trait include the same preventive measures that all athletes should take:

  • Adequate hydration
  • Acclimatization to
    • Heat
    • Altitude
    • Exercise
  • Preseason training and conditioning
  • Allowing gradual progression of exercise
  • Allowing longer periods for recovery between repetitions and workouts

Return to Play
Participants with known sickle cell trait should follow the injury prevention guidelines as outlined above and consult with a physician prior to participation in an activity.

AMSSM Member Authors: Nick Monson, DO, Fran O’Connor, MD


Madden, Christopher C. MD, Margot Putukian MD, Craig C. Young MD and Eric C. McCarty MD. Netter’s Sports Medicine. Philadelphia: Saunders, 2010. Print.


“Sickle Cell Anemia.” The American Society of Hematology, 06 Sept. 2013. Web. 10 Feb. 2014. .


Category: Hematology (Blood) Issues,






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