Sickle Cell Disease and Trait in Athletes

Making news last night in the world of sports medicine, an athlete recently diagnosed with sickle cell trait played in the city of Denver at high altitude.  Why did this make news? For years, many athletes from recreational to professional have deferred physical activity at high altitude for fear of having a sickle cell crisis.  This made the news that a player performed without complications in the spotlight of national TV. 

What is Sickle Cell Disease/Trait?

Sickle Cell Disease (SCD) is a mutation in hemoglobin, the oxygen-carrying component of your red blood cell.  This change in hemoglobin causes the cell to become abnormal.  Normally flexible and oval-shaped, RBCs in SCD lose their flexibility and assume a rigid, "sickle" shape.  This change in shape hinders the ability of RBCs to travel through vessels.  Since the role of RBCs is to carry oxygen throughout the body, sickling prevents oxygen from getting to vital areas, leading to complications. 

Those who have 2 sickle cell genes from their parents present with SCD, while those who receive just 1 gene and 1 normal hemoglobin are referred to as Sickle cell trait (SCT). 

Those with SCT typically don't present with major complications as seen with SCD.  An estimated 8% of African Americans are SCT carriers.

Athletes and SCD/SCT

Most athletes with SCD don't participate in physical activity.  Those with SCT do't do intense physical activity for fear of exertional sickling.  Causes are low levels of oxygen such as higher altitude like Denver or mountain climbing or high intense exercise, overheated muscles, and RBC dehydration.  If it does occur, it usually occurs within 3- 5 minutes of all out exercise.  The sickling will lead to blockage of the blood vessel and lead to breakdown of blood supply.  This can be life-threatening. 

Exertional sickling is extremely dangerous to athletes and ranks as the number four cause of nontraumatic sports deaths in high school and college athletes.  In the past 40 years, exertional sickling has killed at least 15 football players.

Signs and Symptoms

Sickling collapse due to exertional sickling is often confused with cardiac and heat collapse.  Other signs and symptoms include Cramping, pain, inability to catch your breath, fatigue, and generalized muscle weakness.


Sickle crisis is a medical emergency. If you have an athlete with know SCD/SCT, then proper steps should be thought out ahead of time in case of a crisis.  Including evaluation, oxygen administration and transport to the hospital if need be. 


  1. Gradual progressions in training with longer periods of rest.
  2. Stopping activity if any symptoms arise as above.
  3. Hydration is important to maintain.
  4. Avoid heat stress.
  5. Having oxygen available
  6. Educating athletes, and parents on the signs and symptoms.


If you are concerned, or an athlete and would like to be screened for Sickle cell disease, call the office at 480-664-4615.  A simple blood test can be drawn and consultation as well. 


Eichner ER. Sickle Cell Trait. J Sport Rehabil 2007; 16(3):197-203

Holmes PS, Kerle KK, Seto CK. Sickle cell trait and sudden death in athletes.  Am Fam Physician 1998; 58 (8): 1760-1761.