STRESS: Why You Must Have Balance — Part 1
Dear Longevity Insider,
Stress is an everyday word that we can all relate to. Understanding what happens in our bodies when we encounter a stressful situation is the first step towards creating harmony and stability in our lives.
In a previous blog, we used our friend, Jack, to illustrate how the body responds to stress. We discuss the mechanisms behind the central stress response system, the hypothalamic-pituitary-adrenal (HPA) axis, how it regulates the cascade of hormones that the body uses to navigate a stressful situation, and the impact that process has on the body.
Interconnected to this hormonal response process lies the autonomic nervous system (ANS), which comprises two opposite, yet complementary branches called the sympathetic and parasympathetic nervous systems. The ANS is part of the peripheral nervous system that regulates the function of your internal organs, cardiac muscle fibers, and glands, without conscious control.
The yin and yang of stress
The autonomic nervous system also plays an essential role in helping to maintain homeostasis, or internal stability and balance, in the body, where it is constantly fine-tuning bodily functions based on the signals it receives from the central nervous system. How it does this depends on which branch of the ANS is activated at any given moment. Both branches affect the same organs, but they create contrasting effects on them.
The sympathetic nervous system (SNS) is what triggers the well-known ‘fight or flight’ reaction in the body, or what is also known as the E division: exercise, excitement, emergency, embarrassment. What’s very interesting about this is that the nerve fibers of the SNS are located between your thoracic and lumbar vertebrae and lie very close to your spinal column. The name comes from the Greek words "feeling together." This location means that the synapses, or communication, between nerves necessary to initiate a bodily reaction to stress can happen more quickly and affect many organs at once.
The parasympathetic nervous system (PSNS) is responsible for the "rest and digest" response in the body, or what’s also called the D division: digestion, defecation, diuresis (urination). These nerve fibers are located above and below the SNS nerves, in the base of the brain and the sacrum, above your tailbone. "Para" in Greek means "beside," so this system is aptly named for being "beside the sympathetic." The PSNS normalizes bodily functions when it has the time and energy to do so, thus its nerve fibers are further away from the spinal column, sometimes even in the organs themselves.
The all-important messenger
One of the 12 cranial nerves that serve motor and sensory functions is called the vagus nerve. On page 165 in my book, The Longevity Equation, I mention that “The vagus nerve is the longest cranial nerve in the body. It runs through the brain stem, esophagus, lungs, heart, digestive tract, and all the way down to the colon.” Although referred to singularly, it is a pair of nerves that emerge from the left and right side of the brain stem. It’s no surprise then that its name originates from the Latin for "wandering."
The vagus nerve works hand in hand with the parasympathetic nervous system during the "rest and digest" response in the body. When we are not stressed, the vagus nerve serves as a communication superhighway, sending sensory information from the peripheral system to the brain so it can monitor function, and transmitting motor signals from the brain to the rest of the body, such as:
- Keeping the larynx open for breathing
- Feeding oxygen into the lungs and diaphragm
- Slowing and regulating the heartbeat
- Stimulating the secretion of saliva, release of bile, and peristalsis (contraction) of the bowels
- Contracting the bladder
- Sending messages to the brain to produce/release oxytocin (feel-good/bonding hormone)
- Reducing anxiety and depression
- Reducing inflammation
- Increasing immunity and longevity
On Thursday, in Part 2, let's discuss the "tipping point" and how you can "shift the scales."
Until then, stay safe and calm.
To your longevity,
Anil Bajnath MD
CEO/Founder, Institute for Human Optimization
Chief Medical Officer, Longevity Insider HQ
* Today's content has been provided by the Institute for Human Optimization (www.ifho.org).