Here are some interesting facts about the human cardiovascular system that we really don’t give enough thought to.
If we consider that the human heart beats around 70 times per minute that means that each day your heart beats over 100,000 times (70 beats X 60 minutes X 24 hours) is equal to 100,800 beats. Now, in a year that number is over 36 million heartbeats. The average life expectancy for a Canadian male is around 80 years old, so doing the math on that brings us to somewhere around 3 billion times give or take a couple of heartbeats.
With each heartbeat the heart pushes out 2.4 ounces (68 ml) of blood. In 1 minute that amounts to just under 5 litres; almost all of the 5 1/2 litres of blood we have in our body.
Over the course of a day the equivalent of 7200 litres of blood will be pushed through the heart and all that blood travels through a network of arteries, veins and capillaries that, if connected end to end would stretch out to be approximately 96,000 Kms long. That’s more than twice the circumference of the earth! Along the way, 20-25% of the cardiac output passes through the kidneys at a rate of about 1.2 litres per minute where excess water and waste can be expelled through the urine. This means that your blood will be filtered through the kidneys over 300 times each day.
Over time, some of the blood cells will deteriorate and some can be lost through cuts, wounds, nosebleeds, surgery, donations and also for women through their menstrual cycle. Although the body has the ability to replace this lost blood; white blood cells may take 2-5 days to be replaced and red cells can take up to 4 months to be replaced.
There are about 6 large arteries in the body, of which the aorta is the largest with a diameter of just over one inch. Its the arteries that deliver the fresh oxygen rich blood to all the cells, tissues and organs of the body. As the arteries move away from the heart they branch off to smaller arteries more along the size of spaghetti and then to the smallest of the blood vessels called the capillaries which can be smaller than the diameter of a human hair. The oxygen depleted blood is returned to the heart through the veins; a system of blood vessels that completes the 96,000 Km circuit so the whole process can begin again.
If you were in charge of a mechanical system that you relied on, that worked so hard day in and day out, I’m quite certain you would have a maintenance schedule in place to check its performance on a routine basis. Currently, in Canada one of these systems goes down every 7 minutes never to be started again. When is the last time you checked the performance of the system you rely on every day?