The Anatomy of Stress


 Grace Moy O’Brien 

(published in EZ Australia vol. 15-18/19)

It is an all too familiar feeling. The racing of your heartbeat, shortening of breath, tightening of muscles, clenching of jaw and fists. And before you know it, you are in full-on stress mode. The mechanism of stress is extremely complicated and neuroscience is constantly updating our understanding of it. 

One of the pathways associated with stress is the Hypothalamic-Pituitary-Adrenal (HPA) axis which connects the central nervous system to the endocrine system. Adrenaline is delivered into your system via this HPA axis. 

Imagine you are face-to-face with a tiger. Your life hangs in the space between you and the tiger. You are holding a spear in your hand. You feel your heart pounding, your breath is coming out in short sharp bursts. The muscles in your arms and legs tighten, as you feel the surge of adrenaline through your body.  Do you run or do you fight?

 This is commonly know as the fight or flight response. 

The hypothalamus is involved in the mediation of emotional responses, the regulation of body temperature and the regulation of metabolic processes. It also secretes hypothalamic hormones that either inhibit or stimulate the release of hormones from the pituitary gland. 

The pituitary gland is often referred to as the master gland. It controls the other parts of the endocrine system; adrenals, thyroid, testes, and ovaries. When it receives messages from the hypothalamus to either stimulate or inhibit hormone production, it sends signals to other endocrine glands to either inhibit or stimulate their own hormone production. 

The adrenal glands are located on top of each kidney. They secrete cortisol, adrenaline, aldosterone, and small amounts of sex hormones, amongst other hormones. We commonly associate the adrenals with stress because adrenaline is one of the important hormones they secrete. The hormones secreted by these glands are largely responsible for the fight or flight response. 

Coming back to our example of the tiger face-off. At this crucial moment of possible imminent death, the hypothalamus releases a hormone called corticotropin-releasing hormone (CRH) . This in turn signals the pituitary gland to produce adrenocorticotropic hormone (ACTH), which in turn prompts the adrenals to secrete adrenaline, noradrenaline, and cortisol. Adrenaline increases your heart rate and noradrenaline raises your blood pressure. Cortisol increases blood sugar and prepares your body for fight or flight. This loop is perpetuated until the hormones reach the level your body requires, or the danger is over. When that happens, a switch is flicked and a negative feedback loop begins. 

What happens if the tiger above was instead a spouse you are constantly fighting with or an unpleasant and stressful work environment you are faced with daily? This HPA loop then is switched pretty much on a constant replay mode. When this happens, the body is not given a chance to recover and replenish. We then live by these hormones of stress which may lead to cardiovascular issues, adrenal fatigue, high blood pressure or anxiety to name a few. 

How then do we mitigate the effects of stress? 

  1. Physical exercise - this lowers the stress hormones and helps in the production of endorphins and serotonin, your feel good hormones. In addition it may improve the quality of your sleep. 

  2. Meditation. 

  3. Mindful breathing - never underestimate the power of the breath. Inhale to a count of 4, and exhale to a count of 4. During the exhale, focus exclusively on the exhale and the feel of the breath leaving the body. Repeat for 10-12 breaths. This helps to reverse the production of stress hormones. 

  4. Herbs - herbs such as withania and rodhiola help the body adapt to stress, and St. John’s Wort, lemon balm and passion flower may help ease stress and anxiety. 

  5. Magnesium, which may encourage relaxation and sleep.

  6. Laughter, which is always the best medicine. What’s more, it’s free!

Grace O’Brien