The normal situation

The human body is an amazing thing! From anything that man has constructed, nothing comes even close to the ingenuity of our body. As a doctor I am confronted with so many fascinating aspects of our body, but here we will focus on blood pressure.

In our daily life we often take it for granted that we can walk upright, think while we are standing up and move from a sitting to a walking position without falling over. We see the blood vessels in our body as a simple transport system, a kind of plumbed piping that transport our blood to all the organs. But this only functions if there is pressure on the system. Compare it to the waterpiping of your house.

If you open the tap, you expect water. however, it will only flow if there is pressure. This pressure is maintained by the waterpump. Very similar, in our body, the heart pumps our blood through our bloodvessels all day and night and the whole system of heart and bloodvessels adjusts to new situations in our environment (changing body position, sudden stress) many times per second. Imagine yourself sitting. The very moment you stand up, the the blood in our body will need to pump against gravity, and all your muscles ask for more blood to do their work. An interruption in the blood supply to the brain would cause instant loss of conscience. How does this all work?

Our body has a stunning system in place to mainstain the bloodpressure. The second you stand up, tiny sensors in many bloodvessels will register that the pressure drops and that the brain immediately needs to secure a sufficient blood supply. The blood vessels in our skin and in other less vital body parts contract and there is immediately more blood available. The second thereafter, out heart will start beating stronger and faster (you can feel that) to put more pressure on the system. After this, many other factors (amongst them are hormones) will keep the bloodpressure up until we sit down and relax again. An important, and well known hormone is adrenaline, produced by the adrenal glands that are sitting on the top of our kidneys. We all know the situation of a sudden fright, like a pedestrian crossing in front of our car. Our body needsblood to be pumped around faster to respond in a split second and be ready for all muscles to prevent a disaster. The adrenals get the signal to immediately release a lot of adrenaline. The bloodpressure shoot up and we can respond to the emergency. We all know this feeling and realise it when we feel our hears pounding when the fright is over. The wening off of this response gives us that very funny, nervously-relaxed post adrenalin rush.

The adrenalin rush is a good response, but our blood pressure system can also cause disease, when unneccesarily and over prolonged time the blood pressure remains elevated. This is what we call hypertension.

The meaning of blood pressure

Two numbers are used to describe blood pressure. the systolic pressure (the higher and first number) and the diastolic blood pressure (the lower and second number). Health dangers from blood pressure may vary among different age groups and depending on whether the systolic and/or diastolic blood pressure is elevated.

The systolic blood pressure is the force that blood exerts on the blood vessel walls as the heart contracts to pump out the blood. High systolic pressure is now known to be a greater risk factor than diastolic blood pressure for heart, kidney and eye disease and a strong predictor for an early death in the middle aged and elderly. The wider the spread between the systolic and the diastolic, the greater the danger (it points to a lack of elasticity of the blood vessels).

The distolic blood pressure is the measurement of force as the heart relaxes to allow the blood back into its ‘pump chambers’. High diastolic blood pressure is a strong predictor of heart attack and stroke, especially in young adults.

Measuring Blood Pressure

We measure blood pressure with a so-called sphygmo-manometer. Blood pressure is measured in so-call millimeters mercury (mmHg). As the most of you have experienced, a cuff is placed around the upper arm. The cuff is then inflated and will block all the blood flow in the arm 9that is why if it is left on too long it causes that funny feeling and often pain in the lower arm, a sign of the lack of fresh blood). The person taking the bloodpressure then puts the stethoscope over a big artery in the elbow. At first he/she will hear nothing as the flow is completely blocked. the cuff is then slowly deflated and the moment where some blood will push past the cuff, a sound os pulsing blood can be heard. this value is noted as the upper (systolic) blood pressure. With the stehoscope we will hear this sound that disappear once the blood flow is restored to normal by further deflating the cuff. the moment of disappearing of the sound is noted as the diastolic blood pressure. Easy, isn’t it ?

Normal and abnormal Blood Pressure

The criteria what we find normal or abnormal change over time. Modern ideas see the limits being pushed down and down. Not all doctors necessarily agree with too low a target as it is hard to achieve (many drugs to be taken) and too low blood pressure is a risk as well (one could faint).

Normal Blood Pressure (systolic/diastolic) Systolic below 120 mmHg

Diastolic below 80 mmHg
Pre-hypertension (also called normal-to-high-normal bloodpressure) Systolic 120-139 mmHg

Diastolic 80-89 mmHg

Note: 139/89 or below should be the minimum goal for everyone. people with diabetes or kidney disease should strive for 130/80 or less
Mild hypertension (Stage 1) Systolic 140-159 mmHg

Distolic 90-99 mmHg
Moderate-to-severe hypertension (Stage 2) Systolic over 160 mmHg

Diastolic over 100 mmHg

 

Note: If one of the measurements is in a higher category than the other, the higher measurement is usually used to determine the stage. For example, if systolic bloodpressure is 165 (stage 2), and diastolic is 95 (stage 1), the patient would still be diagnosed with stage 2 hypertension. A high sysolic pressure compared to a normal or low diastolic pressure should be a major focus of concern in most adults.

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