Friday, 3 June 2011

Fight or Flight - The Stress Response


The stress cycle consists of the following stages:


When you are first stressed the brain signals the adrenal glands to produce about 40 hormones, most importantly adrenalin and cortisol.  The adrenalin effect kicks in immediately, while the cortisol one lasts for longer.  These both give a boost to your blood sugar.  In fact, the average “adrenal rush” of a commuter stuck in traffic supplies enough glucose to keep him running for two kilometres.  The adrenal glands also release the hormone DHEA (dehydroepiandrosterone), which helps maintain energy and resistance to stress.  As a result of this rapid deployment of adrenalin, cortisol and DHEA, we have more oxygen and sugar available, push more blood to the brain and muscles, and are instantly more alert.  In fact, many people will create stress in their lives just to experience the stimulation.


When the body needs to continue its defence mechanism beyond the initial “fight or flight” response, it enters the adaptation phase.  Cortisol and DHEA have a reciprocal relationship, so as cortisol levels go up, DHEA levels fall.  We start to feel the effects of long-term stress, with increasing anxiety, fatigue and mood swings.


When we become stuck in the stress response or when it becomes chronic, we enter the dangerous territory of the exhaustion phase.  No longer can we produce the necessary cortisol to respond to stress.  Our DHEA levels plummet.  We become depleted of vitamins, including vitamin C, the B vitamins, and essential minerals such as magnesium.  Our energy plummets and, since adrenalin is derived from the “feel-good” neurotransmitter dopamine, excess adrenalin demands lead to dopamine deficiency.  Consequently our emotions take a dive into depression.


The extra energy liberated by adrenal stimulation comes at a high cost.  In the short term, stress does the following:
  • Suppresses the immune system, increasing the risk of infections
  • Slows down the body’s rate of repair
  • Slows down the metabolism
  • Robs the body of vital nutrients

There can be physical symptoms:

  • Recurrent headaches
  • Vague aches and pains
  • Dizziness
  • Heartburn
  • Muscle tension
  • Dry mouth
  • Excessive perspiration
  • Pounding heart
  • Insomnia
  • Fatigue

In the long term, stress:

  • Promotes rapid ageing
  • Leads to weight gain
  • Increases the risk of developing osteoporosis, high blood pressure, heart disease, cancer and digestive problems

On an emotional level, when our brain runs out of feel-good chemicals, we experience the following:

  • Anxiety, fear, restlessness
  • Irritability
  • Depression
  • Loss of libido
  • Impaired memory and concentration
  • Excessive smoking and/or drinking

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