Physiology of stress
The word ‘stress’ evolved from a term meaning to ‘to pull apart’. We call our response to a stressful event, a negative emotion just because it doesn’t feel good inside our bodies – we feel pulled apart. Within seconds, negative emotions affect our breathing and heart rhythms. These patterns communicate to the brain to respond with the ‘fight or flight’ reaction. The reactive brain then goes into action to cause the body to produce adrenalin and cortisol (the stress hormone). The slow-reacting thinking brain is short-circuited and stress hormones divert blood glucose to muscles so we can take quick actions to protect ourselves. The heart and breathing rates become irregular (see HRV plot). In addition, less glucose is available to the memory part of the brain – the hippocampus. However, under chronic cortisol, the hippocampus actually shrinks and memory is permanently impaired* so that our mental and physical flexibility to react to life in an intelligent manner is diminished. How often have we noticed, our brain just hurts when we are under stress. When we are upset, we say and do things that we regret later. We become forgetful when we are in a crisis.
In this fast-paced world of long working hours, email, and cell-phones, our stress level has become chronic. Just like the frog that doesn’t jump out of the pot which is slowly heated to boil, we believe the stressful modern life is ‘normal’ ... until we are ‘cooked’. Every time we share our stressful stories with each other, we recreate that same physiological response in our bodies and in others. We are blind to the impact that this stress has on us until our physical bodies have become diseased. As parents, we pass along our stress to children. Chronic stress affects the developing brains of our children. More details on the long and short term physiological impacts of stress can be found here from the Franklin Institute.
Although we cannot always change our environment, we can learn to change our emotional response and make this a habit in 4-6 weeks!
In the same way that listening to music affects our moods - our emotions color the world we see. When we experience positive emotions, the variability in the heart rate, the breath, and blood pressure follow a very regular pattern that is called coherence. In this state, the heart and brain communicate harmoniously and the hormonal soup including cortisol and DHEA are in the perfect balance to produce optimal thinking. Based on numerous studies in the past 20 years, heart rate variability (HRV) is the best measurable indication of “feeling good” in the moment (see HRV plot). When the brain recognizes this regular pattern, oxytocin (the nurturing hormone) is emitted and blood flow to the cortex (thinking brain) is increased. After 5 minutes of care, a key immune system antibody becomes elevated for at least 6 hours. After 5 min of just recalled anger, this same antibody was depressed for at least 6 hours.** Most amazing is that regardless of age, body type, or sex – when we experience positive emotions, the heart rhythm varies over a 10-second cycle!
The amplitude of this heart rate variability HRV (shown above) decreases with age for yet unknown reasons. In fact, it has been proposed that low HRV is a marker for increased risk of mortality.§ Perhaps this is caused by life-long stress and chronic cortisol.
Core-Herence coaching can teach you how to increase your HRV using the emWave PSR or emWave Desktop to feedback your progress!