Low Blood Pressure | Hypotension
Low blood pressure or hypotension is persistent abnormally low
blood pressure. Blood pressure is the pressure of blood in your
arteries.
The blood circulation is a closed system in which the pressure
varies constantly. It rises to a peak, called the systolic pressure,
at the height of the contraction of each heartbeat.
Then it falls to a lower level, called the diastolic pressure,
which it reaches just before each heartbeat. The diastolic pressure
is the running pressure between beats.
Blood pressure varies between individuals and throughout the
day. Blood pressure is normally above 90/60 mmHg. Your blood
pressure varies by large amounts, depending on what you are doing.
The lowest blood pressures occur when you are asleep or if you
relax all your muscles. Standing up, exercising or anxiety all
cause an increase in blood pressure. In a single day your blood
pressure may vary by 30 to 40 mmHg systolic with similar proportionate
changes in diastolic pressure. This is why when you have your
blood pressure level assessed it is so important
to have it measured under the same conditions every time.
If you are considering buying a machine to measure your blood
pressure at home regularly see the information about blood
pressure monitors.
Where can I buy an accurate Blood Pressure Monitor?
Medisave are leading suppliers of medical equipement
to health professionals and the public in the UK
What are the symptoms of low blood presure?
Hypotension usually means blood pressure that is lower than 90/60
mmHg (millimeters of mercury) or is low enough to cause symptoms.
When the blood pressure is too low there is inadequate blood flow
to the brain and other vital organs, light-headedness or fainting
may occur.
A common type of hypotension is postural (also known as orthostatic)
hypotension, in which suddenly standing leads to light-headedness
and fainting.
Symptoms of low blood pressure - Symptoms of hypotension may include:
Treatment
Generally if you feel well then treatment is unnecessary. Checking
whether you are drinking enough and are not dehydrated may be
important.
If an underlying disorder, such as a heart condition is suspected
then you may be advised to go to hospital for tests and treatment.
If your medication is suspected of causing hypotension the doctor
will probably advise a change of drug or dosage.
Causes of Low Blood Pressure
-
Adverse effect of certain drugs, including
diuretics, anesthetics, nitrates, calcium blockers, certain
types of antidepressant drugs and drugs for the treatment of
high blood pressure
-
Dehydration (Heavy sweating, loss of blood,
severe diarrhoea
-
Vasovagal attack (Fainting)
-
Suddenly standing from lying or sitting position
(postural, also known as orthostatic hypotension)
-
Shock due to internal bleeding, severe infection
or heart failure, heart attack or an irregular heartbeat
-
Anaphylaxis (a severe allergic response)
-
Diabetic neuropathy or peripheral neuropathies
-
It can also be related to pregnancy
What should I do if I think I have got low blood pressure?
The first thing to do is to have it measured either by your doctor
or practice nurse, or get a machine
to measure it yourself. It is important to measure your blood
pressure not just when you are sitting, but also when you are lying
down and standing up. If when you stand there is a large fall in
blood pressure and you feel dizzy, you should then seek further
advice.
If your systolic pressure is above 80mmHg with no drop when you
stand up, and you feel quite well, then you are one of the few lucky
people who naturally have very low blood pressure. For reasons that
are not fully understand you are protected from the effects of salt
and other factors that can cause raised blood pressure levels. On
average, you will live longer than people with higher blood pressures.
Investigations
Investigations are only conducted if you have symptoms that suggest
a fall in blood pressure when you stand up, ie, dizziness or faintness.
If you do have these symptoms or a fall in blood pressure when
you stand then your doctor should conduct further tests or refer
you to a specialist. This will mean having a tilt test where you
will be strapped to a table and tilted, with careful measurements
of heart rate and blood pressure taken. Hormone levels in your
blood may also be measured to check that your adrenal glands and
nerves are working normally.
How is low blood pressure treated?
This will very much depend on the cause. If you are well with
no drop in blood pressure when standing then you should congratulate
yourself – you do not need any treatment. However, if you
do have symptoms then treatment will depend on the underlying
cause. If you are taking blood pressure lowering drugs they may
need to be changed, particularly if you are taking an alpha blocker
such as doxazosin. You will need to discuss this with your doctor
or practice nurse. Many people find that by getting up slowly
their symptoms can be avoided.Failure of the adrenal glands can
be treated by replacement of the missing hormones. If you have
a disease of the nerves then this can be more difficult to treat,
but you may respond to drugs that stimulate the nervous system.
You may also find that wearing elastic stockings or an anti-gravity
suit, or taking hormones that cause retention of salt and/or eating
more salt can help. Talk to your doctor for more information.
Is low blood pressure associated with tiredness or depression?
Many years ago it was thought that blood pressures below a systolic
of 90 mmHg could lead to tiredness and depression and many women
were wrongly treated for low blood pressure with drugs that stimulate
the nervous system. Large studies have now suggested that there
is no relationship, provided there is no underlying cause for
the low blood pressure.
Taken from Your
blood pressure Blog
|