Most people have experience having your blood pressure taken and perhaps a blood test, but what do all those numbers and names and abbreviations actually mean? It is also World Blood Donor Day on 14th June.
Systolic, diastolic, CBC count, WBC count? Even if you are a medical drama TV fan, at best, it can be difficult to pick up the lingo and at worst, be downright frightening. Knowing the basics of how your circulatory system works and learning some of the medical terminology may help you make some informed decisions about your own health care and certainly have a better understanding as to how important blood circulation is to every organ in the body.
All of your blood circulates around your body in about a minute, depending on general fitness, heart rate, the size of your heart and your body size and weight. A healthy heart will pump, on average, 65-75 times a minute, with each beat circulating 60—70 millilitres of blood. The average adult carries about ten pints of blood, which accounts for about 7% of the total body weight.
Everyone belongs to a specific blood group, which is categorised according to the protein or antigen on the red blood cells. This is called the ABO system. Blood is also categorised according to RhD system, which means that the blood either has a D antigen – and 85% of the population do - or is RhD negative, which is rarer.
The most common type of blood is O negative, with 44 % of people carrying this type.
The next most common is O positive, accounting for 37 % of the population.
The rarest type of blood is AB negative, a category consisting of 1% of the population.
It's vital to know your blood group in an emergency situation, though it will always be checked. If you are in need of a blood transfusion, you must get the type of blood that matches or works with your own type.
Type O can donate to any other type, but an A type, for example, can not use a transfusion from a B donor.
Almost every check up at the GP or hospital will involve a blood pressure check. This is given in two numbers. The systolic pressure is the pressure of the heart beats, the force of the blood against the arteries. The diastolic pressure measures the heart relaxing between beats. Normal blood pressure is usually under 120 systolic and under 80 for diastolic, but these figures are meaningless for the layperson.
All we tend to know is that high blood pressure is bad and is a contributing
factor to coronary heart disease. Whilst the inverse is not true, that low blood pressure is good, it is less of a medical concern, although if your blood pressure is consistently low it can reduce oxygen supplies to the brain and make you feel dizzy or faint. This is why it's vital to raise the legs above the heart with someone who has fainted, to get the blood circulating back to the heart. Alternately, if you feel faint, putting your head below your legs can help the blood circulate more freely to the brain.
Another standard medical check on the blood is a Complete Blood Count, or CBC. This measures the different parts of the blood and helps determine those that are too low and those that are too high. The main parts of the blood are the red blood cells, which carry iron, oxygen and other nutrients to the cells. The white blood cells help the body fight infection. Platelets help your blood clot or stop bleeding if you have been injured. Plasma is the liquid that carries all the other components of the blood. Immunoglobulins, made in the white blood cells, are antibodies which help you recover from infection or, in the form of immunisation, protect against infection.
A CBC measures all these things in great detail and can provide vital information about any suspected illness or anaemia, which causes fatigue and lots of other unpleasant symptoms. A very high white blood count could be a symptom of an infection or a more serious condition, such as cancer.
There may be a time when you are unwell and are in need of a blood transfusion. If you are a fit and healthy and weigh over eight stone, it's a good idea to donate blood because it is always needed. Stored red blood cells can only last 42 days and platelets only last for five days. There is very little risk to the donor, as a donor health check is given to rule out any underlying problems.
There is also very little risk to the recipient, because doctors check the blood for many different infections.
Have a think about it during National Blood Donor Day. You get a nice lie down, a drink and biscuits when it's all over (typically ten to fifteen minutes), a very big feel good factor. In fact, you might need someone else's blood to feel good yourself one day.
Visit the World Blood Donor website for more information
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