HOW STRESS AFFECTS THE BODY?
We are born with innate survival responses such as “fight or flight and “rest & digest”. While both are equally important, the fight or flight response is more of a hot topic due to its link with chronic stress and inflammation. I think rest and digest deserves a mention too! So read on till the end to find out more…
Fight or Flight
Let’s say that our life is indeed in danger. And real danger such as running away from a predator!
What physiological changes take place when we face a threat? The sympathetic nervous system (SNS) stimulates the release of corticotrophin-releasing-hormone (CRH), which then signals the adrenal glands to produce adrenaline and cortisol. The activation of the SNS happens really fast as its purpose is to get us ready for emergencies.
Pathway: Hypothalamus > SNS > Adrenal Glands > Adrenaline & Cortisol
- Increases alertness and focus
- Works on the short-term
- Draws blood to the muscles and the brain
- Increases heart rate and blood pressure
- Expands the lungs
- Remains high for longer
- Invites stored glucose and fat from the liver to the bloodstream
- Stimulates protein breakdown in muscles
- Impairs digestion
- Decreases immune function
- Inhibits reproductive function
- Reduces thyroid activity
Other than modern digital age daily stressors (commuting, social media likes, traffic jams, money problems and the list goes on), the following can also raise cortisol levels:
extreme mental anxiety
Cortisol peaks at early morning gradually drop during the day and lowest at night. Most of us are still on the high when we should be sleeping, and in the long run, this can lead to insomnia and exhaustion.
In simple terms, this is how it goes:
stress > cortisol release> withdraw stored glucose from the liver to produce temporary energy to fight > blood sugar level increase
Chronically high blood glucose levels result in two things:
1. damage to the blood vessels and nerves – inflammation, hello!
glucose activates proteins that eventually cause the narrowing of the blood vessels > increased blood flow > increased blood pressure > damaged blood vessels > plaque build-up (from circulating fat from the diet and stored fat that is released from the liver ) at the damaged blood vessel wall > inflammation (the body’s natural response to heal the damaged area)
2. the pancreas gets exhausted as it needs to produce insulin more frequently than it should! Without insulin, glucose cannot be utilised by the cells. Now, cortisol suppresses insulin production and inhibits glucose uptake. Cortisol wants glucose to be available in the blood. This is how it is programmed to work.
There is a constant overworking of the organs (liver and pancreas) and hormones (cortisol and insulin).
Blood glucose dysregulation and inflammation are key concerns if cortisol is too high!
Have you heard of cortisol resistance?
Yes, it does exist! The idea behind the different “resistances” (insulin, leptin, cortisol, and even thyroid cells experience resistance) is the exhaustion of receptors. Every cell has a receptor sitting on or inside it to receive chemical signals. The receptor can feel overburdened and it shuts down.
Rest & Digest
Thankfully, rest & digest is there to turn off the alarm bells by activating the parasympathetic nervous system (PNS). PNS promotes healing, regeneration, digesting, detoxifying, eliminating, and building immunity. Switching on this route takes longer though! It can only be done by relaxation, whatever that means for you. For example, eating on the go, feeling anxious and stressed during eating will result in impaired digestion and absorption. Taking time to sit down for a meal does magic!
It is the most abundant steroid hormone produced by the adrenal glands. It relieves stress and it is our longevity hormone.
Other functions of DHEA:
decreases body fat
inhibits tumour growth in some cancers
So DHEA kinda balances out cortisol. Chronic stress, however, results in decreasing DHEA. I will look at your DHEA/Cortisol ratio to assess your stress profile if there is an indication that the adrenals are tired.
Visceral Body Fat (VAT)
The body cannot make a difference whether we endure a life-threatening situation or we are stuck in traffic. So it reacts as it is programmed, to fight or flight! It thinks we need to refuel, but in reality, most of us are sitting at the desk without any physical activity. As I mentioned earlier cortisol promotes fat storage in preparation to either release it for energy later or a potential famine.
You must be wondering! Why around the belly? Well, there is a very simple explanation. It is stored around the middle because it is close to the liver. This is where stored fat or carbs are converted into glucose and quickly released for energy.