The Longevity List by Merlin Thomas

Author:Merlin Thomas
Language: eng
Format: epub
Publisher: Exisle
Published: 2017-07-15T00:00:00+00:00

The road to ruin

Blood vessels function in our bodies just like the roads in our cities, allowing for a steady flow of traffic along freeways and major arterial roads, and then venturing off into smaller and shorter streets until we reach our destination.

Like any transport system, the health of the roads is critically important for maintaining the healthy flow of traffic on them. If the surface of the road stays smooth, traffic can flow easily and get to where it needs to go. Smooth roads also don’t offer much resistance, so wear and tear on the vehicles travelling along them is also kept to a minimum.

Over time, changes inevitably occur to the surface of any road due to fatigue and abrasion. A road will typically thicken in some places and become thinner in others, creating an uneven, bumpy surface. This roughness increases wear and tear on any vehicles that passage along its uneven surface, as well as making the sound of the traffic distinctly noisier. As the years go by, the road surface gets stiffer and less flexible. Eventually, small bits might even get eroded and flake off.

Underneath the surface, the base of the road is just as important. It takes most of the pressure load of the passing traffic and usually outlives the surface, which can be continuously replaced. But over time, the packing of the soil beneath the pavement begins to weaken, while at the same time it is put under even more pressure by the stiff upper crust. If no maintenance is undertaken, eventually potholes will form in the road, and traffic will be disrupted.

Importantly, these changes do not occur equally in all parts of the road. The sections that easily become damaged and form potholes the fastest usually have the extra pressure of heavy vehicles or have the added force of breaking and turning the corner. By contrast, a conventional car driving on a well-maintained straight road does very little damage.

Almost the same process of progressive deterioration that happens to our roads also occurs in the arteries and blood vessels of our body, where fatigue, abrasion and general wear and tear lead to changes known as atherosclerosis.

As with the city roads, these changes do not occur equally in all parts of our blood vessels. Our largest blood vessels, like our largest roads, are under the greatest pressure and so are most vulnerable to atherosclerosis. Equally, in those sections of blood vessels where blood flow divides and needs to quickly turn a corner, the extra shear on the road surface increases the wear and tear and the risk of forming potholes.

As the years go by, the surface of our arteries gets stiffer and less flexible, just like our roads. This is simply known as hardening of the arteries. Our blood vessels may thin in some places but thicken in others and may even start to bulge a little bit. This is known as plaque, because from the surface it looks like a commemorative plaque jutting out from a smooth wall.

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