Stress triggers a response in the autonomic nervous system (ANS), which regulates involuntary (automatic) bodily functions. The ANS is divided into the sympathetic and parasympathetic nervous systems.
When we perceive a threat, the sympathetic nervous system (SNS) activates the “fight or flight” response, releasing hormones like adrenaline and cortisol. These hormones increase heart rate, blood pressure and glucose levels, thus preparing the body to respond to danger.
Conversely, the parasympathetic nervous system (PNS) promotes the “rest and digest” state, which helps the body to relax after the threat has passed by lowering heart rate and blood pressure and directing energy toward digestion and recovery.
Chronic stress can disrupt this balance, leading to prolonged activation of the SNS and insufficient activation of the PNS, which can cause hypertension, anxiety, digestive issues and weakened immune function.
So it would be good if we could intentionally activate the peripheral nervous system, right?
One simple way of doing just this is controlled breathing, especially focusing on the out-breath. When we exhale slowly and deeply, it signals the PNS to engage, promoting a state of calmness.
· Inhale Slowly: Take a slow, deep breath in through your nose, counting to four as you do so. Feel your belly rise as you fill your lungs with air.
· Exhale Slowly: Breathe out gently through your mouth, counting to six or eight. Make sure the out-breath is longer than the in-breath.
By making the out-breath longer and slower, we help activate the PNS via the vagus nerve (more of which another time), which slows the heart rate and promotes relaxation.
Here’s a good video on Cyclic Sighing.