What effect does altitude have on a person with sickle cell trait and why ?

Sickle in low oxygen: A person with sickle cell trait only, is ok at sea level, but at high altitudes can get sickling in his red blood cells due to the lower concentration of oxygen at high altitudes. The problem of sickled cells clogging off the spleen is rare, but has happened to some people exercising above 10, 000 feet. Good hydration and avoiding over-exertion might decrease the chances of problems starting.

Anoxia: Agree with Dr. K. If you have to be at high altitude, avoid any vigorous activity and stay hydrated. Lack of oxygen causes sickling. Have a healthy diet, exercise, drink plenty of water, have safe sex, and get HPV vaccine. Wish you good health!