Hemoglobin and human longevity: integrating oxygen transport, redox biology, and aging pathways - a narrative review.

Hemoglobin, the vital protein responsible for oxygen transport in the bloodstream, plays an indispensable role in sustaining life and cellular function. Traditionally viewed through the lens of hematology and respiratory physiology, hemoglobin is now being explored as a key determinant of healthy aging and human longevity. As the primary regulator of tissue oxygenation, its efficiency influences mitochondrial activity, energy metabolism, and organ vitality - all of which are central to lifespan regulation. Emerging evidence suggests that both low and excessively high hemoglobin levels are linked to increased morbidity and mortality in aging populations, underscoring the need for homeostatic balance. The dynamic interplay between hemoglobin concentration, erythropoiesis, hypoxia-inducible pathways, and oxidative stress reveals a complex biochemical network influencing aging at the molecular level. Hemoglobin's oxidative byproducts, if unchecked, can induce cellular senescence, compromise immune responses, and contribute to degenerative conditions commonly associated with advanced age.