Sickle cell O2 consumption

• A. Decreases
• B. Increases
• C. Remains unchanged
• D. Fluctuates

Answer: (B)

Oxygen consumption by tissues tends to rise in sickle cell disease because oxygen delivery to tissues is impaired while metabolic demands can be high, especially during crises or stress. With anemia, arterial oxygen content is reduced, so tissues compensate by extracting more oxygen from the blood that does reach them. This increased extraction means a larger arteriovenous oxygen difference, which raises the amount of oxygen used by tissues to meet energy needs. Although red blood cells themselves don’t consume oxygen, the overall rate at which tissues use oxygen can increase when delivery is limited and demand is elevated, explaining why oxygen consumption moves upward in this context.