As you have just read, under stress the blood system is affected as the body responds to the challenge. Blood is diverted away from the skin and stomach. In the diagram the direction of blood flow in the scalp of a healthy human being with a full head of hair.
As the blood enters the capillary network of the scalp, the blood communicates freely with each other across midline and thus able to establish an effective collateral circulation. The blood goes through the capillary network, nourishing the hair papilla making the hair grow.
When the body is aroused to stress, blood is diverted away from the skin to the limbs to power them for action. The blood supply to the brain is also increased for faster co-ordination, so you have a change in blood flow
As blood is quickly diverted to the brain and limbs, the highest point of the head or the male pattern baldness region is getting very little supply of blood. Remember there are no main arteries in the region only capillaries.
You might find this interesting. A Capillary is only one blood cell wide. A pinhead or a Cubic millimetre of blood Contains five million (5,000,000) blood Cells, so you can imagine just how small these diminutive blood vessels are. Also Whilst under stress the blood is more likely to clot, at this stage the flow in the Capillary network of the scalp is very slow it it is flowing at all. It is my theory that the blood clots in the male pattern baldness region, resulting in the hair not getting any nourishment at all. It is also my theory that parts of the scalp left over a period of time not receiving enough blood to nourish the skin and hair papilla causes the papilla to die. This stops the production of the hair shaft which is what We Want to see. As the body goes back to normal the blood supply to the scalp is not as strong.
Baldness is caused by the impaired circulation of the blood to the scalp. The scalp contains the most complex network of capillaries found in the body and this sets up the greatest demand for blood. At the same time the temples, front and top of the scalp are the hardest places for the blood to reach. Since it has to defy the force of gravity to get there.
