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Stress has been known to literally shrink the brain (59,90) as well as disrupting brain function and promoting inflammation. Stress is notorious for being difficult to define. It encompasses all kinds of stimuli of varying amounts of aversiveness and duration (102). Stress can be physical, psychological, social, acute or chronic, and high or low intensity (103-4) Stress can be defined as an automatic physical response to any stimulus that requires you to adjust to change. Every real or perceived threat to your body triggers a cascade of stress hormones that produces physiological changes. We all know the sensations: your heart pounds, muscles tense, breathing quickens, and beads of sweat appear. This is known as the stress response (62.)
Today the word stress conjures images of running late while sitting in rush-hour traffic, rushing the kids from one activity to the next, and then scrambling to get dinner made, working two jobs, juggling a full college course load with a full-time job (and maybe raising children at the same time), or enduring a stressful work environment with an awful boss. Or sometimes stress comes in the way of bad surprises, such as a job loss, a car accident, the death of a loved one, or the unexpected news like Covid-19.
Yet one of the biggest forms of stress is one that many are unaware of and it’s one we have
the most control over too. This is the stress from chronically poor diets and marginal health
Blood Sugar Imbalances through poor diet choices disrupt brain function by overloading the
body’s stress-handling hormones, which in turn taxes brain function. They also lead to obesity and diabetes. Excess fat is pro-inflammatory and a chronic stressor for the body and brain (91.)
Other common forms of physiological stress that contribute to brain degeneration include smoking, food intolerances and food allergies, anaemia, bacterial gut infections, gut parasites, autoimmune diseases, joint pain and inflammation, poor digestion, and many more.
Any time your body must struggle to compensate for imbalances and poor function, it creates a physiological stress response. If these metabolic issues go on ignored long enough, the brain becomes the ultimate victim.
When a physical or emotional threat looms, the hypothalamus secretes corticotropin-releasing hormone (CRH), which has the job of rousing your body. CRH follows a pathway to your pituitary gland, where it stimulates the secretion of adrenocorticotropic hormone (ACTH), which pulses into your bloodstream. When ACTH reaches your adrenal glands, it prompts the release of cortisol (62.)
While stress itself is not necessarily problematic, the buildup of cortisol in the brain can have long-term effects (92.) Thus, chronic stress can lead to health problems especially the hippocampus, the seat of learning and memory that is the first to be affected by Alzheimer’s disease and dementia (59,93, 94.)
Cortisol’s functions are part of the natural process of the body. In moderation, the hormone is perfectly normal and healthy (92) Cortisol has multiple functions in the body In addition to restoring balance to the body after a stress event, cortisol helps regulate blood sugar levels in cells and has practical value in the hippocampus, where memories are stored and processed (95.) Stress also impacts the brain’s command over the autonomic nervous system, that part of our nervous system that regulates breathing, digestion, heartbeat, organ function, and more
basically all the bodily functions that happen without your conscious input. When autonomic function falters, conditions such as dry eyes, incontinence, and high blood pressure can arise
Let’s look at this in more detail
The brain constantly receives and sends information to and from the body. Ninety per cent of the information is sent through an area in the lower two-thirds of the brainstem called the “pontomedullary reticular formation” (PMRF). The PMRF stimulates our parasympathetic system.
Our parasympathetic system which is in control of our enzyme production, digestion, mucus secretion and other related bodily functions, Also known as the rest and digest system. A healthy brain means good stimulation of the rest and digest system which means we will experience good digestion, good bladder and bowel control, good enzyme production etc.
On the other side of the coin, we have the Sympathetic system (Our fight or flight system). An area of the spinal cord called the intermediolateral cell column (IML) stimulates the sympathetic system. A healthy brain not only means that the PMRF stimulates our parasympathetic (rest and digest) system in a good way but it also reduces the effects of our Sympathetic (fight or flight) system.
The fight or flight system is good for when we need quick reaction like quickly avoiding a collision or running away from a dinosaur or something (The way 2020 has gone this isn’t far fetched.)
Basically, the Fight or Flight (Sympathetic) system helps us react to stress by increasing our heart rate, sending blood away from our organs and to our extremities in preparation for fight or flight. We don’t want the sympathetic system to be engaged all day. Optimal brain function would result in an individual who generally moves through life in a calm, relaxed manner, enjoys good digestion and other body functions and does not suffer from a hair-trigger stress response.
However, with our hectic lifestyles, bad relationships, crappy unsecure jobs, High carbohydrate diets, Traffic and commutes, COVID and so much more it’s like we’re running away from King Kong all day every day because the sympathetic system is engaged too often.
Many of us live in a state of chronic sympathetic activity, always ready to fight or flee. This sets a person up for a downward spiral of brain function, which in turn generates ever-higher levels of stress. It’s like being stuck on a roundabout with no exits. As the brain degenerates, overall firing in the brain decreases. This means output into the
PMRF decreases. If the PMRF decreases the stimulation to our rest and digest system also decreases along with its ability to reduce sympathetic stress from the IML. As a result, stress continues to power up whilst our rest and digest system continues to lose power. The result may be a person living in constant heightened stress, high blood pressure, anxiety, irritability, and a general state of being stressed out.
That’s not all,
Located on the top of the brainstem is the mesolimbic system (midbrain reticular formation) This is an area of the brain concerned with survival, mating, and primitive emotions such as anger and love.
Brain degeneration further contributes to stress by stimulating the mesolimbic system, which activates sympathetic stress. So not only does brain degeneration fail to reduce sympathetic stress, but it also creates more stress by activating the midbrain. Inflammation has been shown to activate the mesolimbic system. Studies show the midbrain is rich with receptors for a cytokine, or immune messenger, called interleukin-6 (IL-6) (96.) IL-6 spikes in response to emotional, chemical, or physical stress, overfilling IL-6 receptors in the midbrain. This, in turn, stimulates the IML, generating a sympathetic response. Just getting into a heated argument with your spouse will raise IL-6 levels and enhance the sympathetic stress response (59.) An angry argument can cause a spike in IL-6 that lasts up to several days. (97)
Lack of sleep, Inflammation and over-exercising can also spike IL-6 (98-100.) If the mesolimbic system gets bombarded with IL-6 too frequently, it develops negative plasticity for stress (101) This means when stress repeatedly activates the midbrain reticular formation (mesolimbic system), it becomes increasingly efficient at responding to stress, so that it takes less stress over time to create the same response. Say you get road rage, at first you rage at someone cutting you up and only just missing you, over time you may just get triggered at getting stopped at a red light.
Basically, this means the brain becomes good at stress, like a footballer constantly practising football they become better at it, Our brains over time become world-class at creating stress. Obviously This is not a good thing, it means that small stuff will start to stress you out. Eventually, it becomes permanently active and easily generates a stress response with very little stimulus. We see this with post-traumatic stress disorder (PTSD) (59).