Historical Context
We have two states in our autonomic nervous system that govern much of our waking life: the stress response and the relaxation response. The relaxation response was described by Dr. Herbert Benson in 1975, and the stress response (“fight or flight”) was described by Dr. Walter Cannon in the 1920s. Cannon also described the process of homeostasis, our body’s innate ability to maintain and restore balance.
Dr. Benson’s research was at Harvard University where there was an interest in seeing if Transcendental Meditation could lower blood pressure. At the time, there were no published studies on TM, and after meeting with Maharishi Mahesh Yogi, Benson’s study commenced. This research led to Dr. Benson identifying, describing, and creating practices to elicit the relaxation response of the parasympathetic nervous system.
Physiological Effects of Relaxation Response
The relaxation response is when our body-mind-nervous system complex perceives safety, calm, and equilibrium, and releases chemicals and neurotransmitters that give a feeling of overall wellbeing, calm, and being settled within. It is a powerful physiological state that counteracts the stress response, and when practices that stimulate this response are done regularly, can create a new baseline for how we respond to external stressors. The effect it has on our nervous system and physiological functions are positive in a variety of ways. Here are a few of them:
Reduction of Excitatory Neuronal Activity
This basically means that we become calmer. Excitatory neurons create a sense of alertness in the brain and nervous system that can lead towards states of hyper-arousal. The relaxation response can help calm disruptive thoughts, reduce anxiety, and create calm by:
- Decreasing over-activity in the sympathetic nervous system
- Reducing firing of neurons in the stress-related brain regions
- Increasing the activation of the parasympathetic nervous system
Neuromuscular Arousal Reduction
Neuromuscular arousal can lead to increased muscle tension. With the down regulation of the sympathetic nervous system, our muscle tissue responds, which lead to less muscle tension, pain perception, along with a sense of deep relaxation, and physical and mental calmness. The outcomes can be:
- Decreased muscle tension
- Lowered heart rate
- Reduced blood pressure
- Slowed breathing rate
Cognitive Improvements
Parasympathetic dominance also has a significant cognitive impact, allowing for the prefrontal cortex to perform its executive functions, such as pro-social engagement, strategic planning, and clear thinking. We experience:
- A reduction racing thought
- Improved focus and concentration
- Enhanced emotional regulation
- Decreased rumination and worry
Integration of Hypothalamic Function
The hypothalamus plays a crucial role in regulating various bodily functions, and greater integration of the hypothalamus with other brain regions contributes to homeostasis and wellbeing. The relaxation response helps integrate hypothalamic function by:
- Balancing hormone production
- Regulating body temperature
- Normalizing sleep-wake cycles
- Improving appetite control
How to Acheive the Relaxation Response
There are a variety of practices that can help achieve this response. Dr. Benson used a method of repeating a single word, similar to TM, but without a TM mantra. For his Harvard experiment, he simply chose the word “one” for people to repeat, and it worked. He identified, originally, four parameters that led to the relaxation response:
- A simple word
- A passive attitude
- A quiet environment
- A comfortable position
10-20 minutes per day are all that are needed to elicit this response in meditation. Yoga and other physical practices can contribute to parasympathetic stimulation, but they can also be overdone, in which case these benefits are not always present. Overexertion and overtraining are common occurrences in all physical disciplines, and Yoga is indeed a physical discipline. The indicators of over exertion and training, distinctions between them, and how to make sure you are within your energetic parameters will be listed in the next post.
