OnFitness Magazine - September/October 2017 - 52

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Humans are designed for
acute stress - like running
away from a predator that
wants to eat you, or
catching dinner.

A historical frame of reference
Before we can even begin to talk about
stress, you have to understand what it is
and how humans have adapted to deal with
it. Humans have evolved on this planet for
millions of years. We have had to deal with
predators, food shortages, ice ages, natural
disasters, rugged terrain, uncertain future
and countless other " stressful " things.
If you think you have it tough today,
imagine walking down the street and
having hungry lions jump out from behind
a dumpster and decide you are for dinner.
Or how about you walk into a food store
and the cashier hands you a spear and
points you toward the wild boar living in
aisle 4. This may seem laughable right now,
but understanding the physiological
reaction of that kind of stress is exactly
what you need, to decipher the impact
stress has on fat gain.
The bottom line is humans are
designed for acute stress - like running
away from a predator that wants to eat you,
or catching dinner. That's because we
encountered these types of stress all the
time through the millions of years we were
evolving on this planet. These stressors
were unnerving, yes, but short-lived.
We also encountered forms of chronic
stress, which usually came in the form of
droughts and food shortages, but they too
usually ended fairly soon. Your physiology
is hardwired to the realities of your historic
ancestors. Whether you are being chased
by a pack of carnivores, fighting a wild
boar, under a severe deadline at work,
facing financial uncertainty or stuck in
traffic, your response to stress is exactly the
same as far as your physiology is
concerned.

The brain adrenal axis
The stress response is regulated by a closely
orchestrated communication between the
brain (your hypothalamus and pituitary
gland) and your adrenal glands (2 little
pieces of endocrine tissue that sit on top of
your kidneys). This is known in science as
the HPA axis (hypothalamic-pituitaryadrenal axis).
You can think of the brain as an army's
central command center. When it gets a
warning that there is an incoming threat, it
sends an immediate signal to the adrenal
glands. In a fraction of a second, the
adrenal glands flood the body with
hormonal signals like adrenaline,
noradrenaline and cortisol, whose job is to
give the body the energy required to stay
and fight, or run like hell.
You know what this feels like. If you
have ever been in a near-car accident, you
probably felt an intense surge of energy
travel through your body that allowed you
to slam on the brakes or swerve out of the
way. That was your HPA axis in action.
This is where things can go wrong. In
the modern day there is nothing to run
from and there is no giant Twinkie monster
you have to kill to get lunch. So instead of
moving in response to stress, you just sit
there with large amounts of adrenal
hormones surging through your body. This
is not a good thing. The major action of
adrenal hormones is to raise the amount of
sugar and fat in the blood to supply the
body with energy. The whole body
mobilizes all at once to supply the body
with everything it needs to survive. The
liver is instructed to kick out stored blood
sugar as well as make some extra.
Muscle and fat aid the creation of new

sugar through the release of amino acids
from muscle, and glycerol from triglyceride
(fat), respectively. In other words, stress
burns fat, sugar and muscle under normal
circumstances. But when stress becomes
recurrent and chronic, fat is usually spared
while muscle is taken.
In a normal, more healthy stress
response, you are able to run your way to
safety or fight your way out of danger. The
process of the intense movement to run
away, or fight back, is just what the body
needs - because that triggers the release of
other hormones like testosterone and
human growth hormone (HGH), which act
to repair damaged tissue and partition
energy usage toward fat metabolism, while
at the same time sparing and even building
muscle. The repair mechanisms of these 2
hormones rebuild the body back leaner,
faster and stronger, improving the chances
that the next stressful encounter will result
in another success. All of this together
feeds back on the brain and the adrenals,
allowing them to stop the alarms and go
back to a rest-and-recovery physiology.
Chronic stress
The problem in the modern day starts
when stress, whether real or perceived,
becomes constant and continuous, and is
not followed by intense activity, and never
ends.
Chronic stress is different because the
stressors continually force the body to
work harder and harder to compensate for
the physiological disruptions. One of the
first and most important things to change
is relative amounts of cortisol. Relative is
an important term, because it means how
much cortisol do you have in relation to
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OnFitness Magazine - September/October 2017

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