Sickle cell crises are caused by constriction of the blood vessels due to the half-moon and stiff shape of sickled red blood cells. Some events or physical conditions can exacerbate this constriction, and therefore trigger a pain crisis.
Cold weather, swimming in cold water, or sudden temperature changes may trigger a pain crisis, or exacerbate an existing one. Dehydration also plays an important role, so it’s best to drink plenty of water and reduce consumption of alcohol (a dehydrating substance).
For people with SCD, it’s safe to do low-to-moderate intensity physical exercise, but strenuous activities that cause shortness of breath should be avoided, as strenuous exercise can result in a pain crisis and other complications. High altitude may also trigger pain crises and other complications, due to reduced oxygen. However, by staying hydrated, taking breaks, and gradually building up exercise intensity, people with SCD can safely travel to, and train at, high altitudes.
Additionally, anxiety and mental stress can contribute to vasoconstriction and affect blood flow, which in turn may have a detrimental effect on people suffering from SCD.[1]