An increase in capillaries helps to increase healing by improving blood flow to the site of injury. Improving blood flow provides muscles with an increase in oxygen that gives muscle energy and so reduces muscle fatigue and weakness. An improvement in blood flow also supplies muscles with an increase in nutrients.
Diffusion, the most widely-used mechanism, allows the flow of small molecules across capillaries such as glucose and oxygen from the blood into the tissues and carbon dioxide from the tissue into the blood.
