Blood pressure and falls
Throughout the course we have heard about how low blood pressure can cause falls. Here we can find out some specific information about how low blood pressure can cause falls.
When we stand upright from either a sitting or lying position, or when we stand still for a prolonged length of time, gravity pulls blood down into our legs. If our body does not respond quickly enough, the blood will drain away from our brain and this results in dizziness, fainting and falls. It can also cause blurred or tunnel vision, fatigue, nausea, loss of concentration and headaches. People usually look very pale when they have low blood pressure.
As we get older our body reacts more slowly to a drop in blood pressure, which is one of the reasons why falls and fainting become more common as we get older. Listed below are some of the conditions which can cause our blood pressure to drop, followed by some of the treatment options.
This is when the blood pressure drops when we stand up from sitting or lying down. It usually causes dizziness, fainting or falls not long after standing up.
The graph below compares the blood pressure in 25 people who stood up quickly after lying down. The red line is their usual blood pressure. The blue line is their blood pressure after having a large glass of water (1 pint).
Vasovagal Syncope (fainting)
Fainting is usually caused by a drop in blood pressure, but is sometimes caused by a sudden slowing down of the heart (learn about this in the next step). Vasovagal Syncope (the medical term for fainting) is usually precipitated by medication, prolonged standing, heat, shock or fear. Most people feel lightheaded before they faint, but as we get older we may not get a warning before we faint.
Carotid Sinus Syndrome
In Week 3 we saw James Frith performing a test which involved rubbing on the neck. This was to see if the gland within the carotid artery which controls heart rate and blood pressure was overly sensitive. If it is overly sensitive it can cause sudden drops in blood pressure or heart rate and this can cause falls, fainting or blackouts.
Treating drops in blood pressure
- Review your medication with your doctor to see if any of them are the cause
- Drink plenty of water to keep the blood pressure stable
- Try wearing compression stockings. These are very tight and are only available through prescription in the UK. They prevent blood from collecting in the legs, but they are quite difficult to put on and take off.
- Physical manoeuvres. By squeezing our knees together, or tensing our arm and leg muscles we can temporarily put the blood pressure up if we feel dizzy after standing up. This helps get the blood flowing back from the legs to the brain.
- Avoiding situations which may lower our blood pressure, such as prolonged standing in the heat. Sit on the edge of the bed for a while before getting up after lying down.
- Medication. We sometimes use medication to prevent the blood pressure from dropping. The most common medications were discussed in Step 4.4.
Some of the conditions on this step can also cause the heart to slow down which can cause falls. We will explore this on the next step.
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