It appears that humans have had the same sort of diseases throughout both recorded and unrecorded history. Since hypertension, that is, high blood pressure, is known now to be a major risk factor for causing arteriosclerosis, then prehistoric man and the Pharaohs may well have had high blood pressure also. Arteriosclerotic disease was of little practical concern 6,000 years ago, since there was no specific treatment known, and no way to measure blood pressure then. Also, arteriosclerotic diseases are associated with aging. Fossil bones of prehistoric man suggest that the average age at death was 30 to 40 years old. Even in the 16th Century age 45 was considered a ripe old age, and diseases associated with aging were much less important. One was more likely to die from infection, accidental injury, or battle wounds.

As late as 1900, the leading causes of death in the United States were pneumonia, tuberculosis, influenza, and diarrheal diseases, including typhoid fever. Early physicians were much more concerned with these problems than with degenerative diseases of old age. Only relatively recently, with medical technology allowing longer life spans, have heart attack, stroke, and "poor circulation" diseases become the major killers they are today.

For centuries little was known of the function of the heart and blood vessels. They were thought by many, in early days, to circulate air and water, as well as blood. The concept of a circulation system, with the heart pumping blood to both the lungs and the body, is a relatively modern idea, dating from the 17th Century. Even in the early 20th Century, many cases of sudden death were being attributed to "acute indigestion" that were actually heart attacks. Medical knowledge has changed constantly over the past several thousand years.

Disease was usually thought of by ancient people as evidence of the displeasure of the gods, possession by demons or witches, or of some evil deed of the afflicted person. Magical and religious rituals were used in an attempt to cure the disease. Some treatment methods were quite severe, amounting to punishment to drive out evil spirits. Mental illness was sometimes treated surgically by opening a hole in the skull (called trephining) to allow escape of demons.

Prehistoric skulls having this type of operation have been found, but it is not really known for what purpose these were done. Head injuries causing bleeding between the skull and the brain are properly treated with this procedure. Gradually more scientific methods were evolved in medical care. In all ages there have always been a few persons who overcame their own superstitions and looked for truth.

De Motu Cordis et Sanguinis... (On the Motion of the Heart and Blood...)
In ancient China, 2,500 B.C., there were physicians writing abstracts of all current medical knowledge. One of the writings was the Nei Ching, which states "All blood is under the control of the heart", and "the blood flows continuously in a circle and never stops". The modern knowledge of the exact blood flow in systemic (body) and pulmonary (lung) circulation was not known, however. The pulse was recognized as a reflection of general health, of heart action, and of blood flow. It was studied and relied upon extensively in ancient China and other countries of the Far and Middle East. They performed a complicated examination of the pulse. They could recognise more than 200 different variations of pulse based on volume, strength, and regularity.

Another Chinese medical writing of that time, the Muo Ching, devoted ten volumes to description and interpretation of the pulse. This included rhythm, time of day, variations in strength and volume, differences between right and left, male and female, etc. There was similar emphasis on observation of the pulse in medical writings from India, 1700 to 1600 B.C. Since arteriosclerotic diseases may be associated with changes in the pulse, it seems inevitable that the effects of these diseases would be noted.

Understanding the nature of the circulation of the blood came with the observations of an English physician, William Harvey. Dr. Harvey began to practice in London in 1602 after studying medicine in Italy at the University of Padua. He became a very successful physician, and was the Royal Physician to King James I, and later, to King Charles I. He was teaching his findings on circulation as early as 1615. He did not publish his discoveries until 1628, in Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (On the Movement of the Heart and Blood in Animals).

As usual for those times, his discovery had to be published in Latin before learned physicians would even consider his ideas. Latin and Greek were the languages of scholarly men. Any investigator who published in English then would have been considered uneducated, and unworthy of notice. This is the reason so many medical terms in English are of Latin and Greek origins. It is also the reason prescriptions formerly were always written in Latin, and Latin abbreviations are still used.