Understanding The Nervous System

Dr. Maya Kuczma | Minute Read

Gut Health, Health, Mind Health, Wellness

The Struggle Is Real

The nervous system enables communication throughout the entire body, in response to the outside world. In an instant, information can be picked up from our fingers and communicated to our brain via the nervous system, such as that the element we just touched is hot. This information triggers a response – the removal of our hand – via motor nerves. The muscles in our arm contract and our hand is pulled away, seemingly before we even realize what has happened. This is our nervous system in action. It is picking up on information from our environment constantly, whether we are conscious of it or not. Due to our nervous system, we are aware of who is around us, the temperature of the room, the texture of what we are sitting on, whether our phone just vibrated, and how safe we are.

The Nervous System – Hijacked

We are subjected to constant input, particularly nowadays, where our nervous system has been hijacked by pings, dings, and rings – a near constant influx of information via our phones, tablets, televisions, and computers. Our nervous system communicates to our hormonal organs, also known as the endocrine system, and together forms the neuroendocrine system. Frequently, due to both the volume and intensity of information we are exposed to, it communicates that we are stressed. Our endocrine system listens and responds accordingly, pumping out cortisol, a stress hormone, to manage these threats.

Calm or Chaos: The Nervous System Decides

The nervous system is composed of the central nervous system, including the brain and spinal cord, as well as the peripheral nervous system. The peripheral nervous system can be further divided into the somatic nervous system, enteric nervous system, and autonomic nervous system. The somatic nervous system includes all the sensory neurons that obtain information from our surrounding, as well as the motor neurons that control skeletal muscles. The enteric nervous system, also known as the ‘second brain’, is the nervous system within the digestion tract. The autonomic nervous system controls all of the body functions we do not have to think about, such as breathing, temperature fluctuations, heart rate, digestion.

Sympathetic vs. Parasympathetic

The autonomic nervous system is further divided into the sympathetic and parasympathetic branches. Often referred to as ‘fight, flight, or freeze’ (sympathetic) and ‘rest and digest’ (parasympathetic), these branches of the nervous system encompass how we react to our environment. If faced with a threat, the sympathetic branch springs into action and we either fight, flight (run), or freeze in the face of danger. Evolutionarily, this was a vital response; we had to respond accordingly to an animal, or opposing human, or we would be killed. During this response, digestion is slowed, heart rate is increased, and breathing rate is increased, in order to aid in our response to the threat. Once the threat was removed, we returned to parasympathetic mode, to rest or digest, our heart rate slows, and we relax. Historically, threats were huge, and sudden, but we recovered well, returning to a more restful state easily. Nowadays, we perceive threats everywhere, between constant noise exposure, traffic, social media, work deadlines, financial stress, and social conflict; the animal never retreats, and we remain stuck in fight, flight, or freeze mode, unable to recover.

The Dangers of Chronic Stress

Picture yourself driving to work. Your body has naturally produced cortisol to promote wakefulness that morning. But as you’re driving, someone cuts in front of you; you honk and swear, feeling your heart racing. While you’re stuck in traffic, your phone pings. You know you shouldn’t check it, but it could be free work. You look and it’s an email from your boss with the subject line ‘URGENT’. You sneak a peek and realize a meeting has been rescheduled and will be taking place as soon as you get to work. You had planned to prepare for the meeting this morning and now will be forced to go into it cold. Throughout all of this, the radio has been blaring; you suddenly realize how loud it is and reach to turn it down, just as it switches to a news alert describing a recent increase in crime. As you park, you grab a granola bar from your bag; you’ll eat it during the elevator ride since you didn’t have time to have breakfast. There will be coffee flowing during the meeting; you’ll drink a few cups to stave off the hunger you would otherwise feel.

Does any of this sound familiar? Does any of this sound stressful? It’s only nine in the morning and already your nervous system has been hyper-stimulated since you woke up.

A morning like this is challenging, but a lifetime like this is incredibly harmful.

Within this stressed state, our muscles become tense, we breathe harder, and our heart rate is elevated. Our nervous system communicates with the hypothalamic-pituitary-adrenal (HPA) axis, leading to a release of cortisol, norepinephrine, and epinephrine, all of which are stress hormones that trigger a variety of physiological responses to stress. Digestion slows, since it was not ideal, evolutionarily, to waste energy digesting food when fleeing from an animal; over time this translates into a chronically under functioning digestive system (1). Our blood sugar increases, to provide us energy to ‘flee’; over time, this leads to dysregulated blood sugar and inflammation, contributing factors to the development of diabetes (2). Chronic stress can also suppress hormonal signalling between the HPA and ovaries and testes, negatively affecting libido and fertility (3,4). Our sleep quality is also affected; rather than cortisol release occurring in the morning to promote wakefulness, it is released irregularly, disrupting our ability to fall, and stay, asleep (5). Chronic stress has also been linked to an increase in visceral fat, which in turn promotes inflammation (6). It is for all these effects, and more, that stress has been linked to a huge variety of diseases including cardiovascular disease, depression, and metabolic syndrome (7-9). Additionally, childhood trauma and stress has been linked to higher rates of chronic diseases later in life, including autoimmune conditions (10,11).

Takeaway: Heal Your Nerves First

In the balance between our relaxing parasympathetic nervous system and stimulating sympathetic nervous system, our own personal yin and yang, the fiery, aggressive, yang-based energy has won out. The go-go-go pace of the Western world is clearly detrimental to our health, continually promoting sympathetic overdrive. What’s worse, many of us have become addicted to hyper-stimulated state, and struggle to break free from this pattern. But without addressing the chronic stress cycle we are caught in, we cannot achieve true healing. Healing our immune system, digestive system, cardiovascular system, or any other area of our body, must begin with assessing the amount of stress we choose to engage in and encouraging our nervous system back towards the dynamic, and flexible antenna it once was.