Capillary Density:
The capillary density in infants is 4,100 per square millimeter; this value falls to 3,342 in adults (Figure 2.11). The faster proliferation of capillaries relative to myocytes occurs during postnatal development, resulting in a final myocyte to capillary ratio of 1.0 - 1.5. This is the case in humans, rabbits, dogs, and rats.
During development mean intercapillary distance decreases from 31 to 18 um.