What are blood vessels?

The role of blood vessels

Carrying oxygen and nutrients, processing carbon dioxide and waste products, regulating body temperature: Blood vessels are an essential tissue for such biological activities.
As the name suggests, blood vessels are vessels through which blood flows. They are an essential tissue for biological activity, including carrying oxygen and nutrients, processing carbon dioxide and waste products, and regulating body temperature. Blood vessels are spread out all over our bodies, in order to maintain the 60 trillion cells that make up the human body. They cover a total distance of 100,000 kilometers (equivalent to two and a half times round the earth), have a total surface area of 3,000 square meters (equivalent to six tennis courts) and are thought to weigh around the same as a human liver. The body contains between four and five liters of blood. The volume of blood pumped by the heart per minute is also around four to five liters. Blood pumped by the heart is carried to different tissues in your arteries. In your capillaries, the blood then supply oxygen or nutrients, or absorb carbon dioxide or waste products to and from individual cells. The cycle is then completed by your veins, which return blood to the heart.

Total weight, length and surface area of blood vessels in the human body The circulatory and pulmonary circulatory system

Aging of blood vessels and Vascular accident

Vascular accident are the cause of death in roughly one in every four Japanese people
The Canadian physician William Osler used to say that“A man is as old as his arteries”. As we get older, our blood vessels become less flexible. They get harder, thicker and narrower, causing hardening of the arteries, or “arteriosclerosis.” This occurs when the cells forming the inner membrane of your blood vessels (vascular endothelial cells) become damaged.
Vascular endothelial cells adjust dilation and contraction of blood vessels and regulate blood coagulation. They play an important role in terms of maintaining vascular functions. Those functions however start to deteriorate with age. Other risk factors known to cause arteriosclerosis include blood pressure, blood sugar, LDL cholesterol, neutral fats and obesity. A combination of any of these factors results in an synergistically increased risk of arteriosclerosis.
If arteriosclerosis stops blood from being supplied to individual cells, it starts to cause damage, particularly in organs such as the heart, brain and kidneys. According to “Vital Statistics” published by the Ministry of Health, Labor and Welfare in 2014, roughly one in four Japanese people dies from a heart attack, stroke or other cardiac event, triggered by blood vessels becoming blocked or damaged.


Causes of death in Japanese people (pie chart)

What is your “vascular age”?

If you have an unhealthy lifestyle or if you are suffering from stress, your blood vessels will age faster.
We’re rarely conscious of the condition of our blood vessels as we go about our daily lives. Nevertheless, our blood vessels are being damaged by a number of risk factors. It is therefore important to be aware of the condition of your blood vessels, if only to prevent a sudden cardiac event.
The most accessible cardiovascular evaluation indicator is blood pressure. There are other more detailed methods however, including conducting an ultrasound examination on your carotid arteries to assess the extent of vascular blockages, or analyzing pulse waves (transmitted through blood vessels from your heart’s pulse) to assess the hardness of your blood vessels. In recent years, a “vascular age” index has been put forward to indicate the equivalent age of your blood vessels based on their condition. It is inevitable that blood vessels will deteriorate and harden with age, but an unhealthy lifestyle or stress can accelerate that deterioration. In some cases, a person’s vascular age is older than their actual age.