What is a common effect of elevated methemoglobin concentration in red blood cells?

Elevated methemoglobin concentration in red blood cells primarily impacts the ability of hemoglobin to bind and release oxygen effectively. Methemoglobin is a form of hemoglobin that has been oxidized and cannot bind oxygen, resulting in decreased oxygen availability for tissues. When methemoglobin levels rise, there is a reduced capacity for oxygen transport, leading to hypoxic conditions in body tissues. This condition can cause various physiological symptoms, such as cyanosis, fatigue, and other signs related to inadequate oxygenation.

The other options, such as increased oxygen transport, normal oxygen delivery, and enhanced aerobic capacity, do not accurately reflect the consequences of elevated methemoglobin levels. Instead, these scenarios would imply effective hemoglobin function, which is not the case when methemoglobin levels are high. Thus, the correct answer highlights the association between elevated methemoglobin and the resulting tissue hypoxia.