There is clear scientific proof that the body makes significant physiological adjustments when stress presents itself. The Sympathetic Nervous System is attributed to be the controller with high blood pressure (or hypertension) usually being one of the changes.
The body initialises a stress response by the Sympathetic Nervous System automatically triggering the Adrenal Glands to produce chemical agents collectively called catecholamines.
We have all heard of adrenaline, well, it the most well known of these so called 'fight or flight' hormones, which when secreted in to the blood prepares the body for emergencies, which one would either be brave enough to square up to and fight, or sharper in making one's escape in the interest of safety.
First of all, the action of these hormones begin wholesale shifts in the body's blood quality and distribution. The 'adrenaline rush' causes more blood to be diverted to the major organs such as the heart, the kidneys, and the brain.
From where is this blood diverted?
The short answer is the skin; for it is the largest organ of all accounting for hundreds of millions of cells which all need to be continuously replenished with blood.
In the face of danger, the Sympathetic Nervous System deduces that the skin is less in need of blood than the other major organs and muscles, and sets about constricting the tiny blood vessels that supply the skin with blood. It is not unusual for the skin to feel cold and even to change to a much paler colour at these times. This action alone is a cause of high blood pressure.
To the heart, the increase in blood flow has the effect of increasing the heart rate. One can visibly see and feel the heart pumping more vigorously and quickly by the movements of our chest and abdomen. This increased heart activity is also accompanied by a rise in breathing rate by the lung's enrichment of the blood with oxygen. This makes the blood a more potent reactant at the points of metabolism.
So where is this enriched increased supply of blood most needed?
Well, apart from the organs mentioned above, it is to the major muscles in the arms and the legs. These are amongst the body's strongest muscles that are actually attached to the skeleton. Because they are voluntary muscles, the arms and legs are able to move at will by nervous stimulations.
In animals, these equivalent muscles would be the red meat that one would see on a butcher's block.
The extra blood (and hence oxygen) diverted to these major muscles causes a greater metabolism capacity in them, girding them with extra strength for the task at hand. One would expect to physically use these limbs in most 'fight or flight' encounters.
The brain also has increased blood and oxygen as it goes about sharpening one's vision, hearing and sense of smell. The pupils become dilated, which although causes heightened vision, can also reduce one's peripheral vision.
One may recall having been in situations of being visually unaware of things in the normal visual peripheral zone whilst concentrating on a particular thing.
It is not possible to mention in this brief writing the myriad of changes that are induced by the brain's activity in the face of stress.
For instance, one's voice may acquire an audible tremor; the hair follicles are known to contract giving the feeling of one's hair standing on end; profuse sweating in the palms and the forehead may occur; because the brain is processing everything so much faster one may get the sensation that things are happening slowly; one may feel nauseous; one's bowels may loosen giving sudden urges to go to the toilet; …..and so it goes on and on…….
There is a further aspect of blood quality to consider. With the body girding itself for apparent eminent danger as it were, it also gets ready for the incidence of injury. Blood is further enriched with platelets.
Platelets are the sticky particles suspended in blood plasma, responsible for clotting and repair when blood vessels are severed. They quickly come together at the site of a cut and stop leaking from the blood vessels. The problem is, even when there is no injuries to speak of, the increase presence of platelets can cause clots to form in the blood anyway, which could get haphazardly lodged in, and cause blockages in important arteries.
With respect to high blood pressure, the most significant physiological changes would be the constriction of muscles in the blood vessels. We have already mentioned that this is likely to extensively occur in the skin, but it also occurs in major arteries such as the coronary arteries as well.
The blood vessels have a muscular middle layer that works in unison with the heart impulses to pump blood through them to the peripherals of the body. Stress tends to send these arterial muscles into a state of constriction, effectively narrowing their internal widths, which consequently cause high blood pressure.
by Bilal Rose, Author in Medicationless Side-Effectless
High Blood Pressure / Hypertension Management
