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| Image by Daniel Newcombe; found at {http://www.flickr.com/photos/newcombe/} |
In my last year of high school, I got a call late one night.
It was concerning family member ‘A’ – she had just had a heart attack. Before I
go any further, she made it through fine. It was a mild heart attack as far as
heart attacks go. I was and am still very close to this woman, so I know her
habits and lifestyle well. She has the ‘Stout temper’ personality that
seemingly no Stout can escape without.
However, what is peculiar about her case is that she lives a
very health-conscious lifestyle. Let me elaborate. ‘A’ has always had a more balanced
diet on her off days than I average at my best. Her meals typically consist of
ample vegetables and some sort of animal protein. Her diet is not unusually
high in lipid or carbohydrate content. And, because of her naturally healthy
appetite, she does not diet, so it stays very consistent. She takes vitamins
every morning and even does regular cleanses that include a nearly
all-vegetable diet and extra amounts of water. She is in tune enough with her
body to know when it is stressed whether by nutritional, physical or
psychological means. She exercises regularly (nearly daily), usually with
balanced cardio and weight lifting. She has used exercise as a method of
stress-management for most of her life.
‘A’ was fifty-two when she had the heart attack. Her diet
and exercise routines had not changed. She was at a very healthy weight, most
likely around 125 - 135 pounds at five feet four inches. She had a
well-providing, stable job. There was only one thing that was different at this
point in ‘A’s’ life; she was right in the middle of a divorce that was ending
an 18 year marriage, with three children.
As you might assume, the doctors could not find a clear
cause of the heart attack. She was perfectly healthy. The best explanation they
could give was an irregular heartbeat. They kept her an extra day just to run
tests because they could not come up with a positive causal problem that had
triggered the attack. ‘A’ had a pretty good idea though. She was
psychologically overwhelmed with the burden of the divorce and her concern with
her kids. She even suggested it to the doctors herself – “it was stress.”
So how does stress physiologically strain the cardiovascular
system so much that it can give a perfectly healthy individual a heart attack?
The obvious answer? – Stress. Though, it is far more
complicated than that. From an evolutionary perspective, the stress response of
our cardiovascular system is ideal. Say you are living 100,000 years ago. You
and couple of your tribal peers go out hunting for a boar. You find one, have
it in sight. You begin strategizing your method to catch it. But something
unplanned happens – the boar starts charging you! Stress response activated:
your digestive tract shuts down and your breathing rate surges. Your body
inhibits the release of sex hormones, while others like epinephrine
(adrenaline), norepinephrine and glucocorticoids spill into your bloodstream,
activating the sympathetic nervous system. Heart rate increase to pump oxygen
quicker throughout the body, glucose energy reserves are released, attention
and response centers in the brain are heightened, and blood flow to skeletal
muscles are top priority. With all this in place, you have a pretty good chance
of escaping that charging boar intact.
This heightened blood flow is well and great when we have
the metabolic demand to match. However, like family member ‘A’, if these
physiologic responses are chronic, you are continually diverting as much blood
flow to your limbs, straining the heart and overlooking other areas of the
body. This is when we see damaging effects.
The cardiovascular system was just not made to take the
continual beating that the stress-induced rise in blood pressure generates. So
the first condition in developing stress-related heart disease is hypertension.
The problem becomes more tricky and engrained when high blood pressure occurs
more often. This causes the capillaries (the small ends of the arteries before
they branch back together to form veins), which regulate blood pressure as a
means to optimize the amount of oxygen and nutrients to local sites, to build
up thick layers of muscle to control this blood flow. Consequently, this
thicker muscle makes the vessels more rigid and actually increases
hypertension. At a certain point, it will increase so much that chronic
hypertension has developed.
This is not great for the heart either as blood is returning
to the heart with greater force. And as a means for the heart to resist and
control this thrashing, it builds up its muscle mass as well. However, it is
just the left ventricle bearing the brunt of this force and so is the quadrant
to develop the most muscle. This condition is called “left ventricular
hypertrophy” and causes the mass of the heart to become lopsided. This in turn
increases the risk of an irregular heartbeat, increasing cardiovascular
risk.
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| A blood vessel with atherosclerotic plaque. Image by The Other Side of Life; found at {http://www.flickr.com/photos/all_around_me/} |
Hypertension has its damaging effect on the blood vessels as
well. As the blood whips faster through the vessels, the branching points
suffer much of the force, creating weak spots in the smooth muscular lining.
Eventually, that lining tears and craters begin to form. This injury initiates
an inflammatory response to heal the tears. Cells from the immune system and foam
cells full of fatty nutrients collect there to restore the vessel lining.
However, the hormones involved in the stress response make the blood more
viscous by increasing blood platelets (which help the blood clot with injury)
likelihood of sticking together. What’s more hazardous is that those stress
hormones increase the levels of fat, glucose and cholesterol circulating in the
bloodstream. All sorts of things can then amass at this weak place in the
vessel wall. At this point, we’ve got atherosclerotic plaque formation.
And if this plaque is dislodged and starts freely moving
through the bloodstream (as a thrombus), it has a chance of getting caught in
some narrower blood vessel causing all sorts of serious problems. As with ‘A’,
something to this effect may have happened with the thrombus blocking a
coronary artery and causing a myocardial infarct, a heart attack. If the same
thing happens to the arteries leading to the heart, one can develop coronary
heart disease, myocardial ischemia and more awful health risks. Block up a
blood vessel leading to the brain, and a brain infarct ensues, a stroke.
Comparatively, this actually happened twice to ‘A’s’ father, eventually getting
the best of him.
These conditions simply accumulate upon each other, making any
additional stressor that much more detrimental. Under stressful conditions, the
sympathetic system is activated. The sympathetic system and parasympathetic
system have an inverse relationship. So if you’re chronically stressed, then
the sympathetic nervous system is chronically active and the parasympathetic
nervous system is chronically inactive. Under these circumstances, it becomes
harder and harder to switch on the parasympathetic nervous system to diminish
the stress response. So in some cases, the stress response itself ensures that
it continues.
What is interesting is that strong emotions increase cardiac
vulnerability, which is worsened under stressful conditions. A strong, adverse
emotion, like anger, doubles the risk of a heart attack during the succeeding
time period (Sapolsky, 2004). Actual causes are tough to study since you can’t
predict when a traumatizing event is going to happen to someone and interview
them to find out how they were feeling before and afterwards.
In one instance, however, a physician collected newspaper
clippings of sudden cardiac death in individuals. He found a correlation
between certain events associated with the deaths, including: the collapse,
death or threat of loss of a loved one, acute grief, loss of status or
self-esteem, mourning, personal danger, threat of injury, and extreme joy
(Sapolsky, 2004). Cardiologists seem to agree that sudden cardiac death is an
extreme instance of acute stress causing ventricular arrhythmia or ventricular
fibrillation.
With relation to my family member - ‘A’, she was certainly
emotionally distressed and chronically stressed. Years of feeling upset, angry,
guilty and defeated certainly fueled the fire that stress was raging. So, as ‘A’s’ case exemplifies, even with
a low-fat diet and plenty of exercise, the repercussions of chronic stress can
stack up against ones health. All things considered however, it could have been
plenty worse. Add in the high-fat diet and sedentism that many post-industrial
people call life, and ‘A’s’ heart attack could have been life threatening.
Reference:
Sapolsky, Robert M. (2004). Why Zebras Don’t Get Ulcers: The
Acclaimed Guide to
Stress,
Stress-Related Diseases, and Coping. New York: St. Martin’s Griffin
Press.
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