Stress can literally change your digestion. Slowing it down or inhibiting it. I only learned this recently.

As someone with a whole host of mild intolerances, I always wondered why some food seemed to bother my stomach so much more some days. But then barely at all on other days. Turns out it was stress all along.

I've always known I struggled with stress and anxiety, but it's only been in the last year that I've been able to recognise how truly dysregulated and overactive my nervous system actually is. After speaking with both my GP and an endocrinologist, I realised all the problems I was experiencing were largely connected. The rhinoviruses that last for months, the aches and pains, the cortisol-induced memory loss...

The memory loss was a hard one. I had friends over for dinner once, then somehow I deleted the entire experience from my brain. I asked them a month after when they were going to come around for dinner, and received the most perplexed look.

In this day and age, so many of us are in the same boat. An overactive or dysregulated nervous system has become less of an outlier and more of a norm.

The information age constantly compels us to do more with less, pushing us to our limits.

It gets to the point that opening that 120th email for the day becomes overwhelming.

"The problem we are facing today - we are perceiving more situations to be stressful that are not actual physical threats. But our body is reacting as if they are," explains psychologist Anna Nikolaou.

"With increasing levels of anxiety and stress the sympathetic nervous system becomes dominant and for many of us, we can be in a chronic low-grade overstimulated state. It can become so familiar to us that it seems to be a “normal” experience."

But it's not normal and there can be dire consequences when we don't get back in control of ourselves and our bodies. It's one of many things I learned in connecting with Nikolaou, a board registered psychologist and a member of the Australian Psychological Society, for advice. For anyone else who may be struggling with an overactive central nervous system, here is what Nikolaou taught me the complications of stress and the importance of breathwork.

What exactly is our central nervous system?

Our central nervous system (CNS) is made up of the brain, spinal cord and nerves - its the body’s form of communication. Its purpose is to interpret information between ourselves and the outside world.

It controls how we think, feel and react and is responsible for learning, memory, physical movement, bodily functions like heart rate, breathing, digestion, regulating body temperature. And also our five senses - sight, hearing, smell, touch and touch.

What exactly can it impact, influence, control within our body?

There is a part of the nervous system that has two roles. The first one is called the sympathetic nervous system (SNS) that prepares the body for fight or flight responses in a threatening or stressful situation. In these situations, your heart rate will increase and your body will release adrenaline, your pupils will dilate for more vision and your digestion and metabolism will slow down so its energy is diverted to other areas of your body.

Once the threatening or stressful situation is no longer present the parasympathetic nervous system (PSNS) is activated which is responsible for bringing the body back to its normal state.

I've heard people talk about an overactive nervous system? But what exactly does this mean? And if so why is it common?

In this fast-paced world with constant pressures and demands we are experiencing more stress and anxiety which is activating our sympathetic nervous system more frequently and causing us to remain in an overstimulated state. The underlying cause of stress and anxiety that we see frequently can be triggered by our thoughts.

Negative thoughts, trying to predict the worst-case scenario in the future as an attempt to control every situation.

Overthinking and worrying that we may not be able to handle a situation triggers stress and anxiety and contributes to an overactive sympathetic nervous system.

What does an overactive nervous system look like in a person? How can you tell if this is an issue you have?

Signs of an overactive sympathetic nervous system we should look out for include a range of physical, cognitive, emotional and behavioural symptoms which can be experienced in a few ways. Physical symptoms might be heart palpitations, high blood pressure and cholesterol, breathlessness, nausea, dizziness, weight gain, body aches and pains, diarrhea or constipation, poor digestion, low libido and weak immunity.

There are cognitive symptoms too like inability to focus, memory issues, poor judgment and increased negative thoughts.

Emotional symptoms might be anxiety, irritability, moodiness and nervousness. And then there are the behavioural symptoms which could look like panic attacks, inability to relax, isolating self, avoiding responsibilities, changes in eating habits, changes in sleep patterns and relying on substances to relax, such as cigarettes, alcohol or drugs.

What are the long-term consequences of an overactive nervous system?

The long term consequences become apparent in the later stages of an overactive sympathetic nervous system as it eventually becomes depleted and communicates to the rest of the body to slow down to store energy for emergencies.

This is when you start to feel fatigued all the time and when you are most likely to rely on artificial stimulation such as energy drinks, caffein, sugar, alcohol and drugs. The problem that arises here is the central nervous system becomes confused as it is trying to slow the body down while you are trying to stimulate it.

This can actually then lead to more long-term health issues such as thyroid and autoimmune conditions.

What are some instant fixes if someone is needing to calm their nerves quickly?

This is where the parasympathetic nervous system comes into play which, I mentioned earlier, is responsible for bringing the body’s functions back to a normal state. There are some effective strategies that can be implemented immediately to activate it and to help calm the body.

A quick fix strategy that can cause an immediate shift is breathwork.

Regulating your breathing by consciously doing a breathing technique will naturally de-stress part of your brain and assist with bringing your body back to its normal state.

A box breathing technique is a quick breathing tool that can be implemented and you can do this easily. Visualise yourself drawing a square box as you inhale slowly for 4 seconds (visualising a horizontal line running across the top), exhale slowly for 4 seconds (visualising a vertical line going down), inhale slowly for 4 seconds (visualising a horizontal line running across the bottom) and exhale slowly for 4 seconds (visualising a vertical line going up as you complete your square box).

This is a very effective technique during moments of anxiety and stress for immediate relief, however practising meditation and breathwork techniques daily and ongoing will help prevent an overstimulated sympathetic nervous system.

What are some long-term practices you’d recommend for anyone seeking to regulate their body?

As I mentioned, daily meditation and breathwork practices are a great way prevent an overstimulated central nervous system and which will help keep it regulated. There is strong evidence that shows ongoing mediation and breathwork practices dramatically changes the neurophysiology of the brain and can change the anatomy, physiology and function of the brain. For this reason, it is highly recommended that we implement some form of daily meditation and breathwork practice into our routine to help cope with the everyday challenges and to support a healthy nervous system.

Improving our nutrition is another practice that will help keep our nervous systems regulated. Understanding how food can support us and how it impacts our overall mental and physical health will make us more conscious eaters.  The main thing we need to know is that the food we eat closely impacts our metabolic health and mental health - what impacts the gut, impacts the brain. Gut health has been shown to be related to sleep and circadian rhythm, vitamin production, hormone production, immunity and mood. Therefore, we need to be focussing on ways to improve our gut health through foods to help regulate our central nervous system.

The final important approach that I want to focus on, which is essential and effective in supporting the central nervous system, is to identify the triggers that cause the stress and anxiety in the first place.

Making some practical changes to our situation may be necessary to help alleviate stress and anxiety, however for things that are out of our control we need to look at ways we can cope better in situations and how we can change our perception of these situations. Catching our thoughts, understanding the way we perceive situations that are not helpful to us and understanding how these thoughts can influence unhelpful moods and behaviour is very effective. Having this awareness can highlight thought patterns that we need to work on shifting. If this is proving to be too difficult to work through on your own seeking support from a mental health professional would be beneficial.

What is something more people need to understand about area of our health?

The main message that I want to deliver here is that our mind and our body work together and influence each other. In this modern world we are too quick to want to stop symptoms with prescriptions, substances or unhealthy behaviours but long term these methods are not effective and can be damaging.

It is through the experience of symptoms that our body is communicating to us that something needs addressing.

We need to start listening to our body and notice what it is doing, and we need to be more in tune with our thoughts and how our body reacts to our thoughts.