Simple Exercises to Stimulate the Vagus Nerve: An Illustrated Guide to Alleviate Stress, Depression, Anxiety, Pain, and Digestive Conditions

Introduction

Many health problems, such as digestive disorders, chronic pain, blood pressure, breathing difficulties or circulatory problems, as well as emotional manifestations like anxiety or depressive moods, often result from our inability to process and cope with the ever-increasing stimuli and demands that the modern world throws at us. The efficacy with which our system – as in, our body and our central nervous system – navigates and responds to these growing requirements is often a crucial factor in our physical, mental and emotional health. These days, our nervous system is constantly in action mode, which often comes at the expense of regeneration and recovery. However, there are things we can do ourselves to improve the situation. If you’re holding this book in your hands, it’s probably because you want to change something about your life and your health. Perhaps you’ve noticed that things haven’t been going as planned for a while now, or perhaps this feeling has come on all of a sudden. Or maybe you have the sense that there are things that should feel different. Perhaps you simply want to do something positive and invest in your long-term health, in which case, that’s wonderful! Whether you want to reduce the symptoms of stress, change your lifestyle or just generally improve your fitness, this book will show you new ways to achieve these goals for yourself.

For some time now, the vagus nerve and its therapeutic effects have been the focus of significant interest, especially in terms of the development of different (self-)treatment options. A close look at the functions and roles of this important nerve shows that its stimulation can have a direct influence on relaxation, recovery and regeneration. When it comes to regulating the nervous system, there is no doubt that activating the vagus nerve is one of the most important tools we can use. However, the vagus nerve works neither independently nor autonomously. Even more important is the network in which it functions. One part of the brain that is especially significant in this respect is known as the insular cortex. You will see this term come up time and time again throughout this book. The insular cortex is the brain area where signals from within our bodies are coordinated with information drawn from our surroundings. The latest neuroscientific findings show that our awareness of our body’s internal processes, also known as interoception, forms the basis for our resilience and our ability to combat stress. Improving the way we process information from within the body and from our surroundings is the basis for a healthier nervous system and therefore holds the key to treating a variety of complaints and symptoms of stress.

With this book, we will be with you every step of the way on your personal journey to better health and wellbeing. In the first chapter, we will provide a basic introduction to the roles of the brain and the nervous system and how they work. The focus will be on the systems that have the capacity to relieve symptoms of stress and bring a greater sense of calm and inner balance. In the following chapters, we will equip you with a variety of exercises and training programmes that you can do at home to support your own health and healing. Whether your aim is to alleviate chronic pain, depressive moods or digestive problems, or you simply want to feel more calm and relaxed, you will soon notice an improvement in your symptoms – but only if you persevere with the exercises.

In fact, that is probably the most important message for you to take away with you: no one has ever been healed by reading alone. So, keep an open mind, keep practising and your hard work will pay off!

Lars Lienhard

Ulla Schmid-Fetzer

Dr Eric Cobb

The role of the brain and nervous system

If you want to take back control of your physical, mental and emotional health, it’s crucial that you pay attention to the intricate workings of your brain and nervous system. The brain and the nervous system control and regulate all the processes in your body. You can think of your brain as the CEO of your body. Focusing on the neural connections and the laws of neural networking will not only help you to understand and categorise your symptoms and problems, but will also give you new ways to actively improve your health. We’re talking here about the brain and the neural pathways, rather than any mental or psychological factors that are often associated with this topic. This book is more interested in the processes of receiving and processing information – in other words, the ‘software running in the background’.

The fundamental aim of the brain and nervous system is to protect the body from danger and to keep it fit and healthy. In simple terms, this involves three significant steps:

•Step 1 – Input: Via the different sensory organs, the nervous system receives information from the surrounding environment, the body’s movements and all its internal processes, such as organ activity and breathing, and transmits this information to the brain.

•Step 2 – Interpretation: These pieces of information are then integrated, analysed and compared with one another.

•Step 3 – Output: The information evaluated is then used to create a plan of action, which is sent to the different parts of the body so it can be implemented.

To avoid any misunderstandings, let’s take a deeper look at the term ‘action’ as how the output commands are actualised in the body. The action we’re talking about does not just refer to activities that are performed on a conscious level, which is how the word ‘action’ is understood in general usage. Rather, the actions referred to in this context are unconscious processes instigated within the body, such as those that regulate blood pressure, adapt the respiratory rate, coordinate muscle tension when moving, or control the formation of emotions and thoughts.

How the brain and central nervous system work: they receive sensory input, which they then process and integrate in order to initiate the next course of action.

Your physical wellbeing, fitness, health and behaviour are largely determined by the quality of the information your brain and central nervous system receive, transmit and process. The range of information received by your brain passes through a sort of ‘danger filter’, which is made up of different parts of the old brain. These parts, which developed early in our evolutionary history, use their integration and analysis functions to ‘check’ whether what you are about to do seems safe. If the brain isn’t sure what is going to happen, it will interpret the situation as unsafe. It’s important for you to understand that these processes are unconscious and happen as quick as a flash. In other words, your brain evaluates what’s currently happening in your body and your surroundings in a fraction of a second, and constantly refreshes this information. To get some idea of the scope and complexity of this ‘danger analysis’, you need to know that the information your brain has to evaluate and assess is coming from every single part of your body. For example, at any given moment your brain is analysing information from all your blood vessels, your lungs, your joints, tendons and muscles in both halves of your body, your vestibular system and from both eyes and ears. Have you ever wondered about the quality of the information inside you? How would you evaluate the information from your own body?

All incoming information is evaluated and checked for potential danger in the old brain.

All this information is analysed each millisecond and is used to determine, to a large extent, the perceived threat or danger to your brain. This is not just about recognising genuine danger, but also judging the predictability of the situation, which is based on the quality and quantity – or lack thereof – of all the signals coming in at any one time. Insufficient information, including that from within your own body, is interpreted by the brain as unpredictable and often as threatening. If that is the case, one specific part of the nervous system is activated more powerfully: the sympathetic nervous system. This system is responsible for making us more vigilant and alert in dangerous, stressful or demanding situations. The counterpart to that is the parasympathetic nervous system, which soothes us and supports recovery. Although both systems are supposed to function simultaneously and in constant interplay with each other, this can quickly lead to an imbalance, at the expense of the parasympathetic system. In order for these two essential elements of the nervous system to resume equilibrium, a sort of ‘mediator’ is required. This is where the insular cortex or cortex insularis comes in. It is only in recent times that the insular cortex has started to receive more and more attention from the scientific community, who have realised what a significant role it plays in our sensory world and interoceptive awareness. It is examined in more detail from page 20 onwards. One of its many functions is to regulate the relationship between the parasympathetic and the sympathetic nervous systems.

In order to improve our health and wellbeing, we have to ensure that the information we receive from our surroundings, our own movements and from within our own bodies is clear and of good quality. This gives our brains a distinct sense of predictability and therefore safety. This allows the brain to regulate all processes at the optimum level, providing the basis for health, wellbeing and fitness.

Of course, the reception and processing of information about the current situation is not the only decisive factor here. Another important element is the correlation and comparison of this information with previous experiences, events or fears, which enables us to better judge the current situation. If the rules that govern the nervous system are not taken into account, it can be very difficult to establish the causes of problems which may have been affecting you for some time. Your brain’s primary concern is to clearly predict a situation, for which it requires any information that can shed light on the current situation.

The quality of this information and its processing forms the basis for the next steps and the actions taken. This means that, if the incoming information is inadequate in terms of its quality or quantity, or if the activity level of the parts of the brain whose role it is to process this information is so high that they are unable to tell the brain that what’s happening is clear, safe and predictable, then the actions and physical processes will be adapted to reflect exactly this message. If this diminished ‘protective mode’ is maintained over a longer period of time, your body’s processes and basic functioning will gradually adapt to these new conditions, which are far from optimal. This ultimately manifests in a permanently diminished state of physical, mental and emotional health and well-being. Possible manifestations of this include: reduced mobility and strength, poor motor control, pain, dizziness, undesirable situation-specific emotional states, digestive or weight problems, as well as more complex phenomena such as symptoms of stress or anxiety, poor body image, difficulties controlling impulses, excessive muscle tension, or constant hypervigilance or combativeness leading to sleep disturbances.

In light of this, all physical processes and all symptoms can ultimately be tracked back to the brain and the central nervous system inadequately receiving, transmitting, processing or integrating sensory information.

How the nervous system is structured

Let’s now take a closer look at the human nervous system. As complex and unique as this might seem at first glance, its basic structure is actually quite well organised and is the same for everybody. Almost every process in the human body is controlled by the nervous system. Its roles can be roughly divided into two main areas:

•Physical movements and/or the facilitation thereof.

•Maintenance of vital functions. These functions are for the most part autonomously regulated, i.e. they are involuntary.

The nervous system consists of one central system comprising the brain and spinal cord, as well as a peripheral system comprising all the other parts. The peripheral system is further divided into the somatic nervous system (which controls movement) and the autonomic nervous system, which is responsible for regulating autonomous functions such as digestion, breathing or regulating your blood pressure and heart rate.

This book pays special attention to the autonomic nervous system, specifically how it interacts with the central nervous system and the brain through its processing and control functions.

The nervous system is divided into two main parts – central and peripheral – which, in turn, are further divided into the somatic and the autonomic nervous systems.

The autonomic nervous system: the sympathetic and parasympathetic nervous systems

The three components of the autonomic nervous system are the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system (ENS). The enteric nervous system is also known as the ‘second brain’ or the ‘brain in your gut’ and is an almost entirely self-contained structure. Despite being very important to our health, the enteric nervous system is not an essential part of the topics covered in this book. Our key focus is on the sympathetic and parasympathetic nervous systems, due to their functions and roles within the body. The sympathetic and parasympathetic nervous systems work together to control the autonomous functions of the body, and therefore to maintain the internal balance between performance and recovery. The sympathetic nervous system deals with action and response, while the parasympathetic nervous system is responsible for rest and recovery. So, when you need to be active, the sympathetic nervous takes over and ensures that all the systems required for productiveness are activated. Then, when you come to rest and relax, the parasympathetic system is activated and initiates the processes required for regeneration.

Increasing resilience with a strong insular cortex

It’s hard to define exactly what ‘stress’ is, and the same goes for its impact on the body. We often think of stress as something external – things we need to do or expectations we have to meet. This is why people often say they are ‘under a lot of stress’, for example. That said, this phrase also incorporates the feeling of being stressed, which in turn describes our physical and emotional reactions to these external (and internal) conditions.

But why do some people respond to difficult situations with (chronic) stress, while others seem to effortlessly recover from them? The ability to cope with stress factors and react well to experiences that derail us is known as ‘resilience’. This is a subject that has received a lot of interest over the past few years, especially as it becomes increasingly clear how difficult it is to create a world without problems or unforeseen events. And here comes the fascinating part: it turns out that there is a correlation between resilience and the ability to efficiently interpret information from inside the body. This means that those with a greater capacity for accurately perceiving and interpreting their bodies and their internal conditions also have more resilience and are better able to deal with external stress factors – a highly desirable asset.

As you will see, the ability to perceive the body’s internal processes and to establish their significance is controlled by the insular cortex. So, if this is working efficiently and is sufficiently active, you will be equipped to deal with the challenges – both big and small – that life throws at you.

At a time when the outside world and the daily rhythm of most people’s lives are becoming increasingly faster and more hectic, there are fewer opportunities for genuine rest, and even our free time is often spent carrying out highly stimulating activities. All of this places a great deal of pressure on the nervous system and can lead to disproportionate activation of the sympathetic nervous system. Without sufficient rest and regeneration, the brain gradually loses its ability to adequately regulate and compensate for these stress factors. The various possible symptoms of stress can affect us on many levels, from digestive disorders to increased blood pressure, unwanted weight gain, anxiety and exhaustion. From a neurocentric perspective, symptoms of stress are the end result of several processes that take place in the brain and nervous system.

The most important question here is this: How can we encourage a healthy relationship between our sympathetic and parasympathetic nervous systems and increase our resilience? After all, this is the only way to establish a healthy relationship between tension and relaxation and improve our health, wellbeing and fitness.

The vagus nerve – the main transmitter of information from inside the body

In order to balance out the activity of the sympathetic nervous system, it is important to do things that have a positive impact on the parasympathetic nervous system and regulate the relationship between the sympathetic and the parasympathetic nervous systems. In this respect, the vagus nerve – as the largest and most important nerve in the parasympathetic system and, as we will see later, one of the main sources of information for the insular cortex – is of particular importance. If we want to use the vagus nerve in a targeted way, we need to understand how this nerve fits into the overall structure of the nervous system and what role it plays. Let’s start by considering the following questions: What does the vagus nerve do? Why is it so important?

The primary function of the vagus nerve is to absorb information from the body and send it to the brain. The vagus nerve also transports information from the brain to the organs, but this is more of a peripheral function. Only about 20 per cent of its fibres are what we would call efferent (i.e. descending) fibres. They send information and instructions from the brain to the body in order to initiate and regulate the autonomous processes, such as the abovementioned organ activity. This efferent pathway is also how anti-inflammatory signals are sent into the body, for example. Among other things, this is a significant factor in rheumatism, allergies and any symptoms relating to inflammation of the internal organs, and is therefore of great importance to our health and general wellbeing.

The vagus nerve mainly runs through the thorax and abdomen and innervates several internal organs.

If you look at the course of the vagus nerve, you will notice that it spans the abdomen, heart, lungs, large parts of the mouth and throat, scalp and ears. It innervates these parts of the body and is therefore responsible for transmitting information between these areas and the brain. This is extremely unusual for one single nerve – in fact, the vagus nerve is the only nerve that runs through the body both as a peripheral nerve and as a cranial nerve, and also innervates areas of the head. The nerve has a wide-ranging course, which branches off in lots of different directions, hence its name ‘vagus’, which comes from the Latin vagari, meaning ‘to roam’ or ‘to wander’. The vagus nerve is therefore known as ‘the wandering nerve’, because it has many tiny offshoots that meander through large parts of the body.

Interoception – how we perceive what’s happening inside our bodies

Irrespective of its size and ramifications, the type of information received and transmitted by this nerve is extremely important. The significance of the information that comes from within the body cannot be overstated. For one thing, this nerve delivers information about the respiratory system – one of, if not the most vital process in your body. It also delivers information about changes in blood gases, heart rate and blood pressure, as well as the activities and condition of the organs. For example, mechanoreceptors – which register the level of gastric distension in your stomach – feed back information about how full you are and therefore regulate your hunger levels. Chemoreceptors deliver information about chemical processes such as fluctuations in the pH value and oxygen levels in your blood, while thermoreceptors monitor temperatures and temperature changes in different parts of your body.

All this information from the vagus nerve gives the brain an idea of what exactly is happening in the unconscious processes that take place around your body. The brain’s awareness of this information is called ‘interoception’, from the Latin inter, meaning ‘inside’ and recipere, meaning ‘to receive’. Interoception is a model which is used to describe the way our brains perceive and regulate what’s happening in our bodies. Along with the vagus nerve, there are several other components involved in this system. Interception incorporates all the systems that receive and transmit information, all the parts of the brain that process and integrate this information, as well as all the systems involved in the evaluation of this information. The interoceptive system is therefore not only responsible for receiving and processing, but is also heavily involved in initiating regulatory processes based on the information received. Normally, the function of the system is to maintain the internal state of the body or to adapt it for changing requirements, such as during exertion, while practising sports or exercising, or even in changing weather conditions. However, if our interoceptive awareness is not clear and accurate, the brain is unable to adequately predict our internal conditions, resulting in our responses – i.e. the output of the brain – being inadequate or disproportionate to the situation.

The concept of interoception or ‘interoceptive awareness’, in which the vagus nerve plays such a key role, forms the basis for the training programme described in this book. The main aim of these exercises is to increase our interoceptive accuracy by improving the way we receive and process information, and therefore how accurately our brain is able to predict the present situation. As one of the most important transmitters of information within the interoceptive system, stimulating the vagus nerve is an essential part of improving our interoceptive input. We will pay particularly close attention to this in Chapter 4 ‘Breathing and the pelvic floor’ and