The Neurohormonal System
Our Neurohormonal system is a complex joint venture arrangement between our nervous system and the hormonal system (primarily hypothalamus, pituitary gland and adrenal glands, known as the HPA Axis).
Image Source: https://www.researchgate.net/figure/Regulation-through-cortisol-mediated-negative-feedback-of-the_fig1_330155843
It is a system that always stays in a hypo-alert mode as it is always ready to respond to any external stress stimulus. The body is designed to alternate between the ‘Fight or Flight’ mode and ‘Rest & Digest’ mode.
‘Fight or Flight’ Mode
This is the fire-up mode! This is the evolutionary explanation of the function of the Sympathetic nervous system. This mode is when the body responds to a potential threat or opportunity. Evolutionarily this is a predator & a prey respectively. John Coats explains this hypo alert mode through a vivid metaphor in his book, “The Hour Between The Dog and the Wolf”…
“Our body is fully prepared for a quick sprint or fight to the finish, but it is being restrained by the Vagal brake. At this point your body resembles a drag racing car – locking its front brakes but guns its engines and spins its back tyres. The principle is that the car accelerates far faster by releasing the brakes on an already revving engine than it does by stepping on the gas and initiating acceleration. The Vagus nerve, restraints the fight-or-flight response, allowing blood pressure and circulating levels of adrenalin to build up, and release its brakes when the news comes out, instantaneously bringing heart and lungs to full speed.”
When presented with a threat or an opportunity, hormones like adrenaline, cortisol, growth hormone and glucagon are released. Such hormones orients our metabolic functions towards the proverbial ‘fight or flight’ response. The orientation typically results in slowing/partially shutting down operations that are not urgent like digestion and activates the urgent functions like focus & alertness of vision, paced heart pumping and deep breathing to supply blood to arms and limbs, liver converting glycogen to glucose raising blood sugar levels etc. In short, this is the catabolic state – a state in which your body is ready to burn up its energy stores, ready to fire!
‘Sleep & Digest’ Mode
This is the ‘calm down mode’. This is the evolutionary explanation of the function of the Sympathetic nervous system. This mode slows your heart rate, stimulates insulin production, and directs blood towards the stomach. You’re ready to ‘chill under a shade of a tree and digest your food.’ This is the anabolic state – a state in which you’re ready to eat, digest and store energy (and enjoy he siesta under the shade)!
Hallmark of Good Health
The hallmark of a healthy body is to swing between these two modes seamlessly – to get to the ‘fight or flight’ mode, hit, run, jump, lift…do whatever it takes and then quickly revert back to the ‘rest & digest mode’. A Spring is a good trope for the systems of central tendency. Imagine this feature like a spring that can be compressed (or stretched) when required; when the requirement is over, it comes back to its normalcy fully & quickly.
This characteristic of this Springy action has two dimensions:
- Range – In the spring metaphor, how much can the spring compress (or stretch). How strongly can you fight? How fast can you run? How high can you jump? How much weight can you lift? In biological terms, it is a measure of the capability of your
- lungs & heart to pump oxygen & blood
- Liver to convert glycogen into glucose
- Muscles to convert chemical energy into mechanical energy
- Vision & mind to focus
- Hand limb coordination and balancing
- Restoration – In the spring metaphor, how much and how quickly does the spring recoil to normalcy. In biological terms, it is a measure of how quickly does your heart rate and breathing revert to normal rates; and do they restore fully or stay at a certain elevated level on a more durable basis.
This is the Yin & Yang of a healthy Neurohormonal System. The nervous system and the hormones work in conjunction to swing the orientation of the body towards a goal and back to relaxation. For a healthy person, the Yin & Yang action is responsive, and restorative.
Take an example of a fast bowler in Cricket. Shoab Akhtar sprinted a 40 yard run-up to ball his toe-crushers. He would muster huge amounts of energy into every ball, showcasing his strength (range). After delivering, he would walk back to his mark again and by the time he turned back to bowl his next, his body (breathing, heart rate) had restored, recoiled fully (restoration)….ready to sprint back again!
The Yin & Yang Disorder – an indication of ill health
Back to the metaphor – an old or unused spring loses its ability to either compress (or stretch) fully or to restore its normal size & shape fully and quickly. It ceases to be supple. It gets hard, rusty and stiff. It loses its range and restoration ability.
In the similar vein, a sure shot sign of losing one’s prime is a rusting Yin & Yang:
- Loss of range – Your heart and lungs can no longer show the same range that they used to in their prime in early 20s.
- Residual Skewness – The body goes into a heightened state, but fails to retrace fully. There’s a residual skew. The system remains in a heightened state of alertness and never reverts to the original calmness. There’s a chronic oversupply of hormones like Cortisol.
This skew opens a Pandora’s Box as a chronic elevated state triggers Insulin Resistance, which in turn triggers fat accumulation in liver and abdomen, which in turn triggers fatty liver, diabetes, High Blood Pressure, CVDs, arthritis and what not! Where the problem emerges is a matter of chance and your body’s tendency. But, wherever the problem emerges, you can pin it back to the chronic stress caused by the HPA Axis imbalance (Yin & Yang Imbalance).
The Irony of Good Stress & Bad Stress
There is good stress and there is bad stress.
Good Stress is typically acute and intense. Our body is antifragile in the sense that it responds to stress by getting stronger. When we test the limits of our capabilities, while pumping iron in a Gym for instance, we put our muscles under intense stress. The stress tests the limits, but only for a brief while. This is good enough to trigger an antifragile response from the body, as it prepares to get stronger to cope up with the stress next time.
Some examples of Good Stress: High Intensity work out, sprint, Fasting, cold shower, blood donation, passionate love making, a brainstorming session, a deadline, a failure or defeat.
Bad stress may be mild or moderate, but chronic or long lasting. Since it is not intense, it doesn’t stand up & get noticed. It is like a persistent undercurrent and mostly goes unnoticed or ignored. It is a form of The Frog in the Hot Water Syndrome.
Some examples of Bad Stress: stultifying job, nagging Boss or spouse, daily office traffic, envy, News, habitual late night binge watching, long distance running, pollution, gluttony.
The Irony of Stress is that we often tend to fear/avoid Good Stress because of its high intensity, but tolerate or ignore chronic stress for its low intensity. This corrodes our innerwares gnawing them bit by bit, until it hits the tipping point somewhere and shows up!
How to maintain the Yin & Yang balance
SImple, not easy (as always!) – just embrace good stressors, and shun the bad ones. As I mentioned earlier, there is an irony in our handling of stress – we tolerate or ignore the bad one and avoid the good one for their low and high intensities respectively. We need to turn this around. Embrace and induce short and intense stressors – like high intensity exercise, fasting and complement them with relaxation – like sleep, meditation, walks, socialising, art. This combination keeps the metaphorical spring lubricated and flexed. A lack of usage and on top of it exposing the bad stress attenuates the range and flexibility of the spring of your Yin & Yang.
If you have read till here and are still curious, another article of mine may complement what I worte here.