During acute stress, there is an activation of the sympathetic nervous system. This stimulates the release of hormones and neurotransmitters (e.g. adrenaline and cortisol) that alter the homeostatic balance of the organism, and creates a state of alert commonly known as “fight or flight” response. 

The parasympathetic nervous system is in charge of conserving and recovering energy, and of eliminating metabolic waste products. This will, in turn, activate the sympathetic response to counterbalance it and to re-establish the balance (optimal state of the organism). But in situations of chronic stress, the individual is unable to reach quick or/and total corporal homeostasis.

The sustained and prolonged stimulation of the sympathetic nervous system has a negative effect, for example unhealthy increase of the resting cardiac frequency and arterial tension. If our pulse before starting to exercise is unusually high, the exercise will be of higher intensity than normal, increasing the physical wear and decreasing the general performance.

The chronic release of adrenaline and cortisol is damaging to the body, usually able to withstand acute stress. Chronic stress results in greater cognitive alteration: lack of focus, depression, fatigue, insomnia, just to name a few.

When the body is unable to regulate, there are other negative consequences such as decreased levels of serotonin (that lead to depression and lack of sleep), muscle break down (decreased muscle tone), frequent injuries, weight gain, and poor overall performance.

When optimal balance is achieved, there is a “coherent” state where all the physiological systems are in harmony; functioning in an effective and productive way and achieving peak performance. There is an increase in blood pressure and heart rate that leads to more blood flow to muscles, and an increased respiratory exchange that provides more oxygen to muscles, all leading to better muscle performance. Additionally, other consequences include the pupils of the eyes dilate to improve the ability to see, and the stimulation of cortical centers facilitate mental clarity to problem solve in a faster and more effective way.