Queensland Police Union Journal

Police Health
Police Health
by Peter Shanahan, Police Health Chairman
FEELING FAINT?
Fainting (medically known as
syncope) usually occurs when there
is a sudden drop in blood pressure
which reduces blood flow and oxygen
to the brain.
Dr Susan Corcoran, a cardiologist
from the Baker IDI Heart and Diabetes
Institute, says, ‘about 40 per cent of
people faint at some point in their
lives, but for some fainting happens
as often as once a week’.
There are many factors that can
cause fainting, including heat, pain,
or distress. Interestingly, The Age
reported that some scientists suspect
fainting may have an evolutionary
benefit; falling over and lying still
in response to blood loss increases
survival chances.
A new study from the University of
Melbourne and Austin Health has
also identified genetic factors where
a child of a frequent fainter will have
a 50:50 chance of having the same
condition.
SYMPTOMS OF FAINTING
Associated symptoms of fainting can
include:
• Dizziness
• Light-headedness
• Ringing in the ears
• A pale face
• Perspiration
• Heightened anxiety and
restlessness
• Nausea
• Collapse
• Unconsciousness, for a few
seconds
• Full recovery after a few minutes
CAUSES OF FAINTING
There are many causes as to why
someone may faint; here are some of
the more common:
Standing up too quickly. Blood
pressure can drop, because blood
does not have enough time to reach
the brain as it fights gravity. The heart
must pump stronger, changing its
rhythm.
Prolonged standing. Because gravity
pulls the blood towards the legs, it
may cause blood pressure to drop.
Extreme heat or dehydration drains
blood away from the main circulatory
system and lowers blood pressure.
Heat dilates veins and lets blood pool
in the lower limbs, restricting its flow
to the brain.
Emotional distress or distressing
events (eg. sight of blood or a
needle). This may be due to the fight
or flight response where chemicals
adrenaline and acetylcholine are
disrupted. Increased acetylcholine
causes the heart rate to slow and
blood flow to reduce.
Severe pain. The vagus nerve
transmits a signal to the brain to
drop blood pressure systemically by
producing more acetylcholine as a
protection measure against trauma
and extreme pain.
Low blood sugar. The brain requires
blow flow to provide oxygen and
glucose (sugar) to its cells to function.
Low blood sugar levels can result in
the impairment of brain and heart
functions.
Anaemia, whether occurring
gradually or acutely from bleeding,
can cause fainting because there are
not enough red blood cells to deliver
oxygen to the brain.
Pregnancy can increase the risk
of fainting in some women due to
reduced blood pressure in early
the stages, hormone changes, and
changes in the circulatory system.
The expanding uterus can also
compress the inferior vena cava (the
large vein that returns blood to the
heart) and can cause orthostatic
hypotension (blood can pool around
the lower limbs and uterus).
Hyperventilating, or becoming
intensely anxious or panicked and
breathing too quickly, may cause
fainting from taking in too much
oxygen and getting rid of too much
carbon dioxide too quickly.
Being ill or sick, vomiting, diarrhoea,
sweating, or inadequate fluid intake
may cause dehydration, which can
lower blood pressure.
Certain medications, including drugs
used for anxiety, high blood pressure,
nasal congestion, and allergies can
lead to fainting by causing a drop in
blood pressure.
Heart rhythm changes. A heart
pumping too slowly, or with an
irregular rhythm, may cause blood
pressure to drop. Additionally, the
heart rate can temporary slow and
cause fainting when the body strains
to urinate, have a bowel movement,
or cough, which can trigger the vagal
response in slowing blood pressure.
TREATING FAINTING
Most fainting will only last a few
seconds, but it may make the person
feel unwell, and recovery may take
several minutes.
If you do not think it is a medical
emergency and a person is feeling
faint, you should help them to
lie down and elevate their feet if
76 Queensland Police Union Journal June 2013