Hats and Heart Attacks
by Lizzie Bennett: Anthrax
there is a myriad of articles published warning us about the dangers
of hypothermia, how to spot it and what to do about it. There are
articles warning about cold injuries such as frostbite, warnings
to the elderly about the dangers of not keeping at least one room
warm. Warnings to get the boiler serviced in case carbon monoxide
builds up if its faulty. We are warned that we may need extra vitamins,
warned to drive carefully, warned to take care if using candles
and warned not to leave the lights on the Christmas tree switched
on overnight. Not once, anywhere in this plethora of warnings have
I heard the one that warns you that you are more likely to suffer
a heart attack if you don't wear a warm hat in cold weather.
in the UK upwards of 20,000 extra deaths occur that are attributed
in one way or another to the cold. These are referred to as 'excess
deaths from all causes' on the official statistics. Now that wording
makes it sound like the medics record which deaths are caused by
the cold. In some cases they do, but in most they don't the figure
is derived by taking the figure for the deaths recorded during non-winter
months and taking it away from the winter months total, the number
left is the excess deaths from all causes figure.
Now, some things
that happen in winter are fully understandable and clearly lead
to more deaths than would occur in drier warmer weather. Road accidents,
domestic boiler incidents, house fires, drowning from falling through
ice, asthma, pneumonia, falls, influenza and so on all have a higher
incidence level in winter than at any other time of year.
There are however
other deaths that occur, that are directly attributable to cold
weather that never even get a mention as weather related. We are
all aware that heavy duty snow shovelling can cause a person to
keel over with a heart attack, but this is not the main cause of
heart attacks during cold weather. Heart attack and strokes, or
to give them their proper names, cardiac arrest and cerebo-vascular
accident are responsible for thousands of cold weather deaths each
year. They are listed on the statistics as exactly what they are,
but as a heart or brain does not have 'packed up due to cold weather'
stamped on it at autopsy it's hard to absolutely say the death was
caused by the weather.
These two conditions
are entirely different but they do have one thing in common...blood.
Both conditions are caused by a clotting of, or restriction of,
the flow of blood through an organ, namely the heart and the brain,
and this is where the woolly hat comes in. Trust me, all will become
is a liquid, it is viscous, it has a stickiness to it that some
fluids, such as water, don't have. Like motor oil, blood becomes
more viscous if its left in the open air, and it becomes more viscous
when it is cooled, and less viscous when it's warmed. So, when it's
trundling around in your blood vessels, for the most part all is
well, it's warm and fluid and goes on it's way doing it's thing.
In some parts
of your body blood vessels are far nearer the surface than you might
think, look at the inside of your wrists, your jugular vein that
you may see pulsing in your neck, the veins visible at your temples,
and in the case of newborns under the thin skin of their scalp.
Here the blood dissipates heat far more readily than it does from
other parts of your body. When it cools, it becomes a little stickier,
a little more viscous. Cool it further still, like on a really cold
day, and it becomes even more viscous. Sticky blood cells stick
together and form tiny clumps, which turn into bigger clumps quite
quickly, certainly within a couple of hours.
So. Lets have
an example. We'll call him Joe. Joe has a desk job in the city,
he travels by train as the congestion charge is exorbitant. He is
fit, going to the gym three times a week and plays football on a
weekend. That and running around after his three kids is enough
he feels. He gets up, showers has a healthy breakfast of whole wheat
cereal and fruit, a glass of orange juice and sets off. He drives
to the station, parks and makes his way to the platform. He is wearing
a shirt, suit and tie and thick overcoat. He realises when he is
standing on the open platform that he's shivering, he has left his
gloves and scarf in the car and doesn't have time to fetch them.
Still the train is hopefully running on time and will be here soon.
The blood travelling around Joe's' body is cooling as it moves past
his unprotected wrists and up to his unprotected neck, a shirt and
tie is not that warm, and on to his unprotected head. As it moves
back down into the protected areas of his body it warms and becomes
more fluid again. He is shivering which increases his heart rate,
making the blood move faster, so more blood is passing the exposed
areas more often and passing through the warm areas at a faster
rate. After a few minutes his blood is slightly more sticky than
it was when he arrived on the platform. He continues to shiver.
A couple of blood cells have agglutinated, clumped together in one
of his veins.
know this has happened, he feels nothing, but the process leading
to Joe's' possible demise has begun. The longer he stands there
in the cold the more cells will bump into the still microscopic
clump and stick to it, increasing its size.
At this point
there are several scenarios:
1. The clot
increases in size lodges in his brain, blocks the flow of blood
and he has a stroke.
2. The clot increases in size lodges in his lungs and he has a pulmonary
3. The clot increases in size, lodges in his heart, blocks the flow
of blood and he has a cardiac arrest.
4. The train comes, Joe warms up before the clot increases in size
and lives to catch a train the next day although possibly getting
a deep vein thrombosis in his leg at a later date.
Today is not
Joe's lucky day. The train is late. The thing with clots is the
bigger they get the more blood cells bump into and stick to them.
By the time Joe gets on the train fifteen minutes later the clot
is no longer microscopic, but it is stuck in place for now. Joe
feels a touch off colour but has put it down to the shivering and
shaking he has been doing for 20 minutes.
He gets of
the train and makes his way to his office, glad to be in the warm
at last. As he settles at his desk, he warms up, his blood gets
less sticky and starts moving at its proper rate around his body.
The clot in his vein gets less sticky also, a lump of it breaks
off and gets carried along with the liquid blood the clot lodges
in Joe's heart. Joe doesn't feel too good, he's a bit pale, his
chest is a little tight, the fingers on his left hand feel odd,
his left arm is tingling. Internally more and more blood cells are
backing up behind the clot, blocking the small gaps around its edges
that was allowing enough blood through to keep his heart beating.
As the blood supply slows, Joe's heart, starved of what it needs
starts to fire off irregularly, the electrical system is failing.
Joe feels a rapid tightening in his chest as the heart strains to
maintain its output. It gives one last flutter before ceasing its
activity. Joe Feels like his chest is going to explode, attempts
to stand up and collapses. Now at this point he is not technically
dead. Although not conscious of it his brain functions will continue
until the oxygen in his body has been used up, but for all practical
purposes Joe has died. He was 43 years old.
die each year of cold related strokes, heart attacks and pulmonary
emboli. Even wrapped up, some people prone to sticky blood will
still die, but a great many more would survive if they dressed in
weather appropriate clothing. It's not rocket science that the colder
it gets the more we need to wrap up. Cover your head neck and wrists
when out in extreme cold. The ankles also have vessels near the
surface so socks are a must, and boots in snow or when trouser legs
are likely to get soaked exposing the skin to excessive cold. Wearing
several layers means you can take something off if you get too hot
and makes managing your temperature far easier.
Do you remember
your mother shouting: "Don't forget your hat, scarf and gloves
or you'll catch your death"? It seems she had a point and thats
the connection between woolly hats and heart attacks.
Stay safe this
from Medically Speaking.