By: Lorenzo Cohen, PhD, Sarah Prinsloo, Ph.D., Alejandro Chaoul, Ph.D.
Stress generally occurs when an event or situation (stressor) places demand upon us that exceeds our coping abilities.
Stressors in our lives are many and varied, but usually are characterized by an event that is challenging, harmful, induces fear or represents loss.
Our hardwired physiological response to stress results in an increase in
sympathetic nervous system activity. For example, when we need to get away from danger quickly, our heart rate increases, we breathe faster and shallower, we perspire, blood is shunted to our muscles and we engage for action.
Under stress, other body systems tend to decrease function, for example digestion, so that more energy can be spent on those systems that will best help the body deal with the stressor. We often refer to this physiological response as "fight or flight."
To counter-balance the sympathetic response once the stressor is over, the
parasympathetic system engages, decreasing heart rate, slowing breathing and relaxing muscles. This allows us to return to our pre-stressor balanced state of functioning.
Our bodies naturally lean toward a parasympathetic state, but when stress becomes chronic we end up living under a constant sympathetic state. The health damaging effects of this chronic stress state are well documented in the medical literature.
Stress and the brainThe brain responds in the "fight or flight" way and, in fact, may be viewed as the major orchestrator of the response; the conductor if you will.
The brain usually shifts into a high-alert, brain-wave activity state while the stressor is present and then shifts back to more relaxed activity once the stressor is gone (usually slower; parasympathetic tone).
Under chronic stress, it becomes more difficult for the brain to switch between sympathetic and parasympathetic arousal. So, the brain and the rest of the body rarely get a chance to recover, even if the stressor is no longer present.
A key factor to managing chronic stress is teaching the brain to become more flexible to help maintain a healthy balance between sympathetic and parasympathetic arousal. Meditation is one method to increase brain flexibility.
How mediation helpsMeditation has been described as "a wakeful hypometabolic physiologic state" in which the practitioner is extremely relaxed, yet alert and focused.
Although meditation methods can vary, most types of meditation share common features. These include the focused, controlled regulation of breathing and control over thoughts and feelings that come to mind, whether the goal is to inhibit and/or acknowledge and release external thoughts and feelings.
Given the continuous attention-based processes involved in initiating and maintaining a meditative state, meditation has been proposed to be an attentional training exercise.
Meditation, among other things, helps bring awareness to the relation between the mind and body -- acknowledging the constant dialogue and bidirectional effect that the mind and body have on each other.
The impact of meditation on the brain
Meditation may help the brain invoke the parasympathetic response to chronic stress, to balance the sympathetic strain. Brain activity is 98% electrical, and brain rhythms are classified into groups according to the speed that they relay information:
- Delta is the slowest and is predominant in sleep states.
- Theta can equal a state similar to daydreaming.
- Alpha is associated with relaxation
- Beta is associated with attention and intellectual activity.
Brain research has shown that the mechanisms of meditation induce electrical frequencies that are thought to be in part the switch between hyper-arousal and relaxation. For example, under meditation conditions the brain often produces the alpha wave. Alpha triggers mental relaxation and is an idle rhythm of the brain, as it waits for cues from other parts of the body and the environment.
This and other brain electrical rhythms affect neurotransmitters, such as dopamine and serotonin, which are also essential in maintaining a healthy balance between sympathetic and parasympathetic arousal and managing the stress response.
Meditation, therefore, helps regulate relaxation in the body through a bidirectional conversation between electrical and chemical messages in the brain and the translation of those messages by the rest of the body.
A feedback loop follows, where the brain receives signals from the rest of the body about the current state of arousal. As meditation with awareness continues, the body continues to relax and achieve a better balance of its functional systems. Consequently, meditation can help to regulate chronic stress, facilitating the integration of the mind and body.
Overall health effects
Meditation research is finding that mind-body practices have an effect on all systems in our body (e.g. immune, hormone, neurotransmitters and even gene expression to name a few), improving aspects of quality of life, and creating fundamental beneficial changes in the way the brain works. The neurological effect of meditation demonstrates the brain's profound ability to change itself through experience.
This new frontier of medicine is revealing how important it is to manage chronic stress and how influential our behaviors are on how our brain works and our overall health and well-being.
Meditation is one such healthy behavior to achieve balance and teach our brain flexibility. Meditation techniques are many and varied. Find a form that works for you and practice daily.
You know that feeling of being so wrapped up in a good book or great movie that you lose track of time or self? That's very similar to what hypnosis is like; it's a state of highly focused attention that allows a patient to concentrate on a self-created image so that the awareness of his or her current environment becomes less important and less clear. 
