Keynote Lecture: Haemoglobin--is more better?

Quality of life is closely linked to our ability to meet the exercise challenges imposed on us by our daily round of activities and those we select as leisure time activities. Aerobic metabolism of fat and carbohydrates provides the energy to support our activities. An increase in aerobic capacity extends the range and duration of activities we can undertake without the premature onset of fatigue. An adequate oxygen delivery, especially to skeletal muscles, is central to the effective aerobic support of energy metabolism. Frequent exercise improves our aerobic capacity by a relatively modest increase in oxygen transport and a large improvement in the capacity of muscle to use oxygen delivered. This is achieved by an increase in mitochondrial density as well as an increase in capillarisation of skeletal muscles. A decrease in oxygen delivery, in active people, produces the same type of adaptive increases in aerobic capacity. Therefore, even though more haemoglobin is clearly better for active healthy individuals, frequent exercise can improve the capacity of renal patients to make the most effective use of their anaemia-imposed reduced oxygen delivery system.