Low blood pressure is also known as hypotension. For the millions of people worldwide who suffer from high blood pressure or hypertension, low blood pressure may seem great. But it can cause serious heart disorders, fainting and also lead to neurological and endocrine or hormone gland disorders.
According to a recent study in the Journal of Age and Ageing, a large number of patients over the age of 70 remain on medication for high blood pressure, despite having low blood pressure. The study states that this has a significant effect on increased admissions to hospital and mortality rates. We will take a more detailed look at the study but first, let us look at some basic information.
What is blood pressure?
Blood pressure, in its most simple terms, refers to the force that your heart exerts in order to pump blood around the body. It varies continually throughout the day, depending on a number of factors – most notably, whether you’re at rest or in a state of exertion.
Both high and low blood pressure can have implications when it comes to your health, so it’s important to understand your blood pressure readings, and know how to improve it, if required.
Blood pressure testing: How is it measured?
Your blood pressure test actually consists of two measurements, not one. The first measures the level of pressure when your heart pumps blood through the arteries and around the body. This reading, which measures systolic pressure, is when your heart is working at its hardest, and the pressure is at its highest.
The other reading is the level of pressure when the heart is at rest, between pumps. This is when the pressure is at its lowest and is referred to as diastolic pressure.
As a result, your reading will always feature two numbers, not one. Your blood pressure is measured in mmHg, which is millimetres of mercury, and the systolic, or higher pressure reading is always first, followed by the diastolic, or lower reading.
What is ‘Normal’?
An ideal systolic blood pressure is 120 or below, though too far below could indicate low blood pressure, which is also a problem. If your systolic reading falls between 120 and 139, this means that you are in the ‘borderline’ category, and that your blood pressure is higher than desirable.
If, however, your reading is 140 or higher, this is considered to be hypertension, or clinically high blood pressure.
A diastolic blood pressure result of 80 is considered normal. If it’s between 80 and 89, it is higher than ideal; if it is 90 or higher, again, this is a sign of hypertension.
So, for example, if you have a blood pressure reading of 120/80, this indicates that your blood pressure is perfectly normal. If you have a reading of 140/90, you’re recognised as having hypertension, which can increase your risk of heart disease and other related conditions.
Our levels of blood pressure can fluctuate by as much as 30 or 40 mmHg during the day. When we are active, very stressed or anxious our blood pressure rises. It will be at its lowest level when we are resting or asleep.
What is low blood pressure or hypotension?
If you have a blood pressure reading of 90/60 or lower, this is regarded as low blood pressure or hypotension. Many people with low blood pressure will experience no symptoms. If the condition is not severe and there are no underlying problems, treatment may not be necessary. The most common symptoms are as follows:
- Blurred vision
- Cold, pale or clammy skin
- Fatigue or general weakness
- Rapid, shallow breathing
What are the types of hypotension?
- Orthostatic or postural hypotension. This can occur when your blood pressure lowers when you change position, for example, when you stand up from a sitting position. This occurs frequently as we get older and our blood pressure should return to normal levels rapidly.
- Postprandial hypotension. This is when blood pressure drops after eating and can cause light-headedness, dizziness and faintness. After we eat our intestines require a large increase in blood supply for digestion. The heart responds by beating faster while blood vessels in other parts of the body constrict to help maintain blood pressure. As we get older, our heart beat may not increase enough to maintain blood pressure which then drops.
To counteract postprandial hypotension, it may be helpful to follow these steps:
- Eat smaller and more frequent meals
- Lower the carbohydrate content of your meal
- Lie down after your meal
What causes low blood pressure?
- Some medications such as alpha blockers, beta blockers, tricyclic antidepressants, diuretics, drugs for Parkinson’s disease.
- Serious burns, injuries or internal bleeding
- Septicaemia, blood poisoning or severe infection
- Problems with the endocrine glands such as the thyroid or adrenal glands
- Heart disease
- Dietary deficiency of vitamin B12 and folate leading to anaemia
- Eating disorders such as anorexia or bulimia nervosa
What is the treatment for low blood pressure?
People with hypotension who display very mild symptoms may not need treatment. The NHS says that a very low percentage of patients who are diagnosed by their GPs are prescribed medications. The possible treatments will depend on what is causing the low blood pressure but may include the following:
- Medications such as fludrocortisones to help boost blood volume or midodrine to boost blood pressure levels.
- A change or alteration of dosage of other medications if these are thought to be causing the problem.
- A referral to a specialist if an underlying problem such as a thyroid disorder or heart condition is thought to be to blame.
- An increase in salt and fluids to increase blood volume and prevent dehydration.
- Compression stockings to help stimulate circulation.
In many cases the dizziness is just a nuisance but if the drop in blood pressure is severe, it may increase the risk of injury from a fall. There is also a higher risk of developing stroke, dementia and other brain disorders.
In the study detailed above, researchers from the University of Kent and East Kent Hospitals analysed the results of over 11,000 patients over 70 years old and found that almost 70% of those with the lowest blood pressure were taking anti-hypertensive drugs designed to lower blood pressure. The authors concluded that the consequences of hypotension due to drugs are potentially costly to the NHS and have a negative effect on the quality of life of older patients. They have recommended that treatment must be regularly reviewed in order to balance the risks and benefits.
Home Monitoring or Doctor’s Surgery: Which is Better?
Most people, when they want to have their blood pressure checked, visit their GP. However, there are a wide range of home blood pressure monitors available to buy, which can prove useful to those who want to keep tabs on their health from the comfort of their own home.
Indeed, according to recent research undertaken at the University of Leuven in Belgium, home blood pressure monitors are particularly useful for patients who have slightly elevated or lowered blood pressure, as it enables easier and more accurate assessment of the condition.
Know the Variables
Of course, when measuring your blood pressure, it’s important to be aware of the variables affecting it. Your blood pressure may vary considerably throughout the day, and this is especially important to bear in mind if you’re measuring your blood pressure using a home testing kit. Age, fitness and pre-existing medical conditions can affect the results, as can stress, levels of activity and lack of sleep.
If you’re concerned about your blood pressure whether it is raised or lowered, it’s important to arrange to speak with your GP.
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