By Medifit Education.
HYPOTENSION/ LOW BLOOD PRESSURE
WHAT IS LOW BLOOD PRESSURE?
Low blood pressure is also known as hypotension and is usually diagnosed with a blood pressure reading that is consistently lower than 90/60 mm/Hg.
Some people have naturally low blood pressure, which doesn’t cause any symptoms. However, if the blood pressure is too low, it can affect blood flow around the body making a person feel dizzy or unsteady.
Blood pressure is a measurement of the pressure in your arteries during the active and resting phases of each heartbeat. Here’s what the numbers mean:
- Systolic pressure. The first (top) number in a blood pressure reading, this is the amount of pressure your heart generates when pumping blood through your arteries to the rest of your body.
- Diastolic pressure. The second (bottom) number in a blood pressure reading, this refers to the amount of pressure in your arteries when your heart is at rest between beats.
Current guidelines identify normal blood pressure as lower than 120/80 mm Hg.
Although you can get an accurate blood pressure reading at any given time, blood pressure isn’t always the same. It can vary considerably in a short amount of time — sometimes from one heartbeat to the next, depending on body position, breathing rhythm, stress level, physical condition, medications you take, what you eat and drink, and even time of day. Blood pressure is usually lowest at night and rises sharply on waking.
The risk of both low and high blood pressure normally increases with age, due in part to normal changes during ageing. In addition, blood flow in the brain declines with age, often as a result of plaque build-up in blood vessels. An estimated 10 to 20% of people over age 65 have postural hypotension.
WHAT CAUSES LOW BLOOD PRESSURE?
The cause of low blood pressure isn’t always clear. It may be associated with the following:
Hormonal problems, such as an underactive thyroid (hypothyroidism), overactive thyroid (hyperthyroidism), diabetes, or low blood sugar (hypoglycaemia)
Overdose of high blood pressure medication
Heart arrhythmias ( abnormal heart rhythms)
Widening, or dilation, of the blood vessels
Heat exhaustion or heat stroke
WHAT CAUSES A SUDDEN DROP IN BLOOD PRESSURE?
- Sudden drops in blood pressure can be life-threatening. Causes of this type of hypotension include:
- Loss of blood from bleeding
- Low body temperature
- High body temperature
- Heart muscle disease causing heart failure
- Sepsis, a severe blood infection
- Severe dehydration from vomiting, diarrhoea, or high temperature
- A reaction to medication or alcohol
- A severe allergic reaction, called anaphylaxis
MEDICATIONS THAT CAN CAUSE LOW BLOOD PRESSURE
Some medications you may take can also cause low blood pressure, including:
- Diuretics (water pills), such as furosemide (Lasix) and hydrochlorothiazide (Microzide, Oretic)
- Alpha blockers, such as prazosin (Minipress) and labetalol
- Beta blockers, such as atenolol (Tenormin), propranolol (Inderal, Innopran XL, others) and timolol
- Drugs for Parkinson’s disease, such as pramipexole (Mirapex) or those containing levodopa
- Certain types of antidepressants (tricyclic antidepressants), including doxepin (Silenor), imipramine (Tofranil), protriptyline (Vivactil) and trimipramine (Surmontil)
- Sildenafil (Viagra) or tadalafil (Cialis), particularly in combination with the heart medication nitroglycerin
IS LOW BLOOD PRESSURE DANGEROUS?
Usually, having low blood pressure is not a cause for concern. However, sometimes your blood pressure can drop to a point where you may feel faint or dizzy.
If you find that your blood pressure is suddenly much lower than usual, there may be a reason for this. Speak to your doctor or nurse.
HOW IS LOW BLOOD PRESSURE TREATED?
Most people with low blood pressure will not need treatment.
If your doctor or nurse feels that you would benefit from treatment, they will often try to find a cause for your low blood pressure. If they can find the cause, they should be able to decide on the most appropriate treatment for you.
Low blood pressure (hypotension) usually only needs to be treated if it is causing symptoms. This will involve general lifestyle advice and treating any underlying cause of the condition.
If you have naturally low blood pressure and it’s not causing any problems, treatment is rarely necessary.
The advice outlined below can often help limit symptoms of some of the most common types of hypotension:
- Stand up gradually – particularly first thing in the morning. It may also be useful to try other physical movements first to increase your heart rate and the flow of blood around your body. For example, stretching in bed before you get up or crossing and uncrossing your legs if you are seated and about to stand.
- Avoid standing for long periods of time – this can help prevent neurally mediated hypotension (low blood pressure caused by miscommunication between heart and the brain).
- Wear support stockings – sometimes called compression stockings, these are tight-fitting elastic socks or tights. They provide extra pressure to feet, legs, and abdomen, which can help improve circulation and increase blood pressure. However, you should speak to your GP before using support stockings because they are not suitable for everyone.
- Avoid caffeine at night, and limit your alcohol intake – this can help you to avoid becoming dehydrated, which can also cause low blood pressure.
- Eat small, frequent meals rather than large ones – this can help prevent postprandial hypotension (low blood pressure after eating). Lying down after eating or sitting still for a while may also help.
Increasing your fluid and salt intake
Dehydration can cause low blood pressure. This can be easily treated by increasing your fluid and salt intake. Ensuring you drink enough fluid will help by increasing the volume of your blood, which will increase your blood pressure.
If you have low blood pressure, you may benefit from having more salt in your diet. Your GP will be able to advise how much additional salt you need and whether you can add salt to your usual food or if you need to take salt tablets. Don’t add extra salt to your diet without seeing your GP first.
Changing your medication
If your GP suspects your medication is causing low blood pressure, they may advise using an alternative medication or may alter your dose.
Your blood pressure should be monitored while you’re taking medication and changes noted. Tell your GP if you are experiencing side effects from taking medication.
Treating underlying conditions
If your GP suspects your low blood pressure is being caused by an underlying health condition, you may be referred to hospital for further tests and treatment.
For example, if your low blood pressure is related to hormone problems, you may be referred to a specialist called an endocrinologist who may prescribe hormone replacement medication.
Medication for low blood pressure
Very few people are prescribed medication for low blood pressure. The symptoms of hypotension can usually be treated by making the above changes to your lifestyle and, in particular, by increasing your fluid and salt intake.
If medication is necessary, it will usually be medicines to expand the volume of your blood or to constrict (narrow) your arteries. By increasing your blood, or decreasing your arteries, your blood pressure will increase because there will be more blood flowing through a smaller space.
By Medifit Education.