The Science behind Yoga and Stress

Yoga is gaining popularity for its role in battling stress, anxiety and depression. Time and again, health and wellness coaches and clinicians have been stressing on practicing yoga for a healthy body and mind. But, what is the science behind yoga and stress?

You may think yoga is just a set of body-bending exercises where you twist your arms and limbs and focus on your breath. But, there is a lot happening under the skin and in your brain while practising yoga. Read on to know what yoga does to your brain chemistry and nerve connections. 

Before I get into that, let’s first discuss the parts of the brain that play a key role in stress.

1. Emotional brain 

This comprises of the amygdala and its connections, medial forebrain structures including the medial prefrontal cortex. 

2. Logical brain 

It comprises of the dorsolateral prefrontal cortex, other parts of the prefrontal cortex, parts of the cingulate cortex and parts of the hippocampus.

The emotional and logical brain serves the functions of emotion and cognitive function as well as play a key role in stress. 

Our emotional brain triggers a stress response via the sympathetic nervous system. And, it manifests as an adrenaline rush and increase in cortisol (stress hormone)  levels in your circulation. 

On the other hand, the logical brain tries to shut down this stress response and restrain the emotional brain. Stronger the logical brain, lower the stress response. Once the stress response is turned off, our parasympathetic nervous system signal is activated. 

Yoga is known to stimulate the parasympathetic nervous system, which in turn initiates a cascade of events like blood directed towards endocrine glands and other organs, lowering heartbeat and blood pressure. This restores a balanced and calm state of mind after major stress is over. 

In short, a strong logical brain and relaxation go hand in hand. 

Related: Meditation and Yoga Can Reverse DNA Reactions Which Cause Stress

Do you know that stress response and the relaxing signals travel through our body in a particular route? And, parts of these routes such as carotid arteries of the neck have switches.  Do you know you can physically manipulate to turn these signals on or off? 

Yoga can train the entire stress circuit at two levels:

1. Yoga activates the logical brain 

Your logical brain is activated every time you are holding a specific yoga posture, concentrating on your breath and trying to balance. As you try to bend forward, lower your head, the yoga posture turns on the relaxation signal through the switches in the neck. Because, bending forwards and lowering our head increases the pressure of the fluid within the cranial cavity, bringing our blood pressure down to compensate for this. 

It means with every yoga posture your logical brain and the relaxation signal are turned on at the same time. This signal is responsible for keeping your emotional brain quite. 

As per brain imaging studies and MRI scans, yoga enlarges our brain. Scientists found that people practising yoga have more brain cells than non-practitioners. With more hours of yoga, you can have bigger brain size. Upon observing the brain scans of yogis, it was noted that they have larger brain volumes in the brain regions associated with attention, our concept of self, and areas critical to lower stress. 

2. Logical brain fights stress response

Whenever you bend backwards, it turns on stress response in your system through switches in your neck (as well as baroreceptors and through signals from other receptors including those within our vestibular system within the inner ear.).  A similar process occurs when you are contracting your muscles.