Biology of stress and effects on health.
Stress is useful in some situations:
Stress isn't always a bad thing. Stress
can be handy for a burst of extra energy and focus, like when you're playing a
competitive sport, or have to speak in public.
It is related to the release of the pituitary hormone cortisol. In emergency situations of stress, it prepares the body for fight or flight response by controlling its metabolism. It gives the body a sudden rise in blood sugar level, by not letting insulin form and control sugar. It provides extra energy to the body for a quick response. You may have noticed that such responses are involuntary and the person can do the things which in normal conditions, he is incapable to perform. Like after an accident people although having severe injuries can fight for their lives and survive, not even knowing the severity of their injuries.
When stress becomes negative:
When stress continues for longer
periods of time, it actually begins to change your brain.
Chronic stress, like being
overworked or having arguments at home, can affect brain size, its structure, and
how it functions, right down to the level of your genes.
Stress begins with something called the
hypothalamus pituitary adrenal axis (HPA axis) a series
of interactions between endocrine glands in the brain and the kidney, which
controls your body's reaction to stress.
As mentioned earlier, when your
brain detects a stressful situation, your body releases a hormone called
cortisol, which primes your body for instant action. Cortisol is known to control
the human reaction by controlling his metabolism, it also has effects on
regulating blood sugar levels, and blood pressure.
But high levels of cortisol over
long periods of time wreak havoc on your brain.
For example, chronic stress
increases the activity level and a number of neural connections in the amygdala, your
brain's fear center.
Harmful effects on health:
As levels of cortisol rise, electric
signals in your hippocampus, and the part of the brain associated with
learning, memories, and stress control, deteriorate.
The hippocampus also inhibits the
activity of the HPA axis, so when it weakens, so does your ability to control
your stress. Cortisol can literally cause your brain to shrink in size.
Too much of it results in the loss
of synaptic connections between neurons and the shrinking of your prefrontal
cortex, the part of your brain that regulates behaviors like concentration, decision-making,
judgment, and social interaction.
It also leads to fewer new brain
cells being made in the hippocampus.
This means chronic stress might make
it harder for you to learn and remember things, and also set the stage for more
serious mental problems, like depression and eventually Alzheimer's disease.
The effects of stress may filter
right down to your brain's DNA. As we know about epigenetics, these stress
responses go down to the next generations as well.
But the good thing about epigenetics is that it can be controlled as well by controlling the turning off and turning on of the genes.
What adaptations and life changes can help us overcome stress will be our next topic of discussion.
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