Low Blood Pressure

What is blood pressure?

Blood pressure is recorded by two numbers: 

  • The first (systolic pressure) is measured as the heart contracts. 
  • The second (diastolic pressure) is measured before the heart contracts.  

Blood pressure goes up and down as a normal response to activities of daily living. It will go up in response to stress or physical activities, and go down when a person is relaxed / resting.

Generally, the normal values for blood pressure are approximately 120/80.

What is low blood pressure (hypotension)?

Clinically significant low blood pressure describes a situation where the blood pressure is low enough to produce one or a number of the following symptoms:

Dizziness/light-headedness (in the extreme this can result in a fall);

Changes in vision, such as blurred, tunnel, greying or blacking vision;

Angina-like pain in the chest;

Weakness and/or Fatigue;

Feeling muddled or confused.

When are these symptoms most likely to occur:

These symptoms are most likely to happen when there is an increased demand for blood for activities throughout the day. For instance:

In the morning, as more urine is generated overnight and the blood volume is lower and as a consequence of lying flat for several hours;

After a quick change in position (postural hypotension), particularly from a lying down to a sitting or standing position;

 − After physical exertion;

After meals, when more blood is needed by the digestive system (Alcohol has a similar effect);

In a warm environment as peripheral circulation increases due to the dilation of blood vessels;

Sometimes, when constipated, the effort of straining lowers blood pressure. 

Illnesses, ranging from a cold to more serious conditions, often as a result of dehydration;

Anxiety can cause over-breathing which lowers the blood pressure.

People are more at risk of low blood pressure if they are older, have diabetes and/or are already taking blood pressure-lowering pills to treat high blood pressure.

Is low blood pressure dangerous?

Not in itself usually, but it can be a hazard because it can cause fainting, possibility resulting in injuries. 

If a person with low blood pressure faints, it is important to NOT try to sit/stand them up.  The lack of blood reaching the brain can cause mild confusion, but this should clear as the blood pressure returns to normal.

 

What are the effects of Parkinson’s disease on blood pressure?

Parkinson’s and almost all the drugs used to treat the condition (levodopa and dopamine agonists) can cause low blood pressure. The most common type experienced by people with Parkinson’s is orthostatic or postural hypotension.

What can be done medically to help overcome low blood pressure problems?

If the dose of the drug to treat Parkinson’s is built up gradually and the precautions mentioned in this information sheet are taken, then individuals will minimise the possibility of experiencing any serious consequences from postural hypotension. In some cases, the hypotension is severe enough to warrant the gradual withdrawal of the drug and its substitution with another drug.

If medication is being taken to lower blood pressure, it is advisable to have it checked as this, combined with the effects of Parkinson’s, may be making blood pressure too low. In some people postural hypotension can also be controlled by using drugs that increase the blood volume.

Some people find that wearing support stockings to stimulate the circulation can be helpful.

Are there any simple strategies that can be adopted to cope with low blood pressure?

Yes, these include:

Do not stay in an overheated environment for too long. Try to curtail unnecessary activity in hot temperatures. Try to keep cool and hydrated with extra fluids;

Try not to sit or stand still for long periods.  Do tasks sitting down, where practical. When doing a task that requires standing then move about a little;

Some dizzy spells can be avoided by taking time to alter positions such as rising from a chair to standing position. On rising, do not walk away from the chair straight away. Before getting out of bed, allow the feet to dangle on the floor for a few minutes before rising. Then rise slowly;

When bending or reaching, do so slowly, holding on to something if needed;

It helps to raise the head of the bed so that less of a postural drop is experienced when standing;

Eating small, frequent meals, increasing fluid intake, avoiding caffeine and alcohol may also help;

Taking some medication on an empty stomach may aggravate the problem;

Recognising what triggers symptoms & what makes them better/worse, will help manage the issue;

Exercise, e.g. leg exercises, flexing the ankle, squeezing the calf muscle, crossing & uncrossing legs. Most of these can be done sitting, standing or lying in bed. A physiotherapist can advise further on exercises;

If feeling dizzy or faint, sit (preferably with legs raised) or lie down immediately, until the feeling passes. Some people with severe symptoms also find it helpful to use a Derby or shooting stick to sit on;

Sometimes, taking a small drink of water before getting up can help.

 

Can low blood pressure affect driving?

Yes, low blood pressure can affect the ability to drive and consequently car insurance.

Acknowledgements from PAI:

Thanks to Parkinson’s UK for permission to use their PDS Leaflets as the basis for a number of our Information sheets.

Thanks to Mags Richardson, RGN, Parkinson’s Nurse Specialist at the Mid-western Regional Hospital, for endorsing this Info. Leaflet.