Critical Anemia 9th Grade Bio, Critical Thinking.?

9th grade bio, critical thinking.? - critical anemia

Persons who are heterozygous for sickle cell anemia, should be avoided that the extreme conditions to significantly reduce the amount of oxygen to the body than traditional sports at high altitude. Explain why it would be desirable.

Need help? : / I have no idea. What does this have to do with heterozygous?