PYP Yoga

How stress works in the body

In order to understand how stress impacts us, we have to first understand the part of our body that handles stress: the nervous system. The nervous system is a complex organ system that includes the brain, spinal cord and nerves, and just like any complex system, it has different departments. The Autonomic Nervous System is the department of the nervous system that is responsible for controlling everything that happens beneath our conscious control. It is comprised of two main systems: the Sympathetic Nervous System (SNS), and the Parasympathetic Nervous System (PNS). These two systems are commonly known for their roles in the fight or flight stress response (SNS), and the rest and digest relaxation response (PNS), and they work hand in hand to keep us functioning optimally, and enable us to handle stress as it arises.

Both systems are necessary and important, but it is the Parasympathetic Nervous System that is primarily responsible for keeping us stress-free and balanced. From a medical perspective, this is achieved by maintaining homeostasis. Homeostasis is the window within which our bodies and minds are optimally functional. Maintaining homeostasis is a dynamic process; our minds and bodies are constantly making adjustments to keep us in our homeostatic state. It’s like balancing on one foot in tree pose during yoga – you manage to stay balanced one on foot the whole time, but that doesn’t mean you’re perfectly still, you’re maybe wobbling a tiny bit to one side, before those muscles kick in and bring you back to your centre point. If you think of your tree pose balance point as your place of homeostasis, that moment where you return to your centre balance point – that’s essentially what the PNS does. It enables you to recover from little shifts and challenges, and prevents you from completely losing your balance.

From an anatomical perspective, the PNS is just a series of nerves that deliver messages to our organs, glands, muscles, tissues and brain, based on sensory input that it receives from the outside world and from our bodies. But its physiological role is very complex and very important; a strong, healthy Parasympathetic Nervous System is absolutely vital to a strong, healthy individual. The PNS enables us to handle stress and stay balanced in many different ways. It is responsible for governing our gastrointestinal system and enabling us to properly digest and absorb nutrients, for controlling our endocrine and reproductive systems and ensuring the appropriate balance of hormones, for helping us heal and recover from a hard workout or an injury, and for keeping us in our calm, rational minds, which allows us to feel happy, present, grounded and able to fluidly experience a full range of emotions.

A stressor is anything that has the potential to push us out of our window of optimal function – a fight with our partner, a difficult test, worries about making our rent payments, an injury. The Parasympathetic Nervous System gets challenged by all stressors that we experience, whether internal or external, and is also responsible for helping us to deal with and recover from those stressors. When we have an accumulation of stressors, without any way to release the stress, the PNS can become overwhelmed and we can lose our ability to handle any of the stressors coming our way.

When we lose our ability to effectively and efficiently return to our place of homeostasis, disease and dysfunction occur. This can show up as chronic indigestion or digestive difficulties, frequent colds and flus, poor or slowed recovery from injury or training, difficulty focusing, poor memory, fluctuating moods, fatigue, insomnia, etc. If we get stuck out of homeostasis for too long, more debilitating things like fibromyalgia, chronic fatigue syndrome, PTSD, and depression can arise.

However – it’s not all doom and gloom! Stress is a normal, healthy part of being a human, and it is inevitable. It helps keep us on track, it motivates us towards achieving our goals, and lets us know when our boundaries have been crossed. The goal is not to avoid all stress, but rather to be able to handle it, learn from it, and bounce back after it, and this is what our PNS enables us to do. There are a number of things that we can do to help strengthen the resilience of our PNS system, and improve our ability to handle stress while staying balanced. In upcoming articles I will talk about and share the research on how breath, movement and mindfulness can all be exceptionally useful tools in strengthening our Parasympathetic Nervous System and improving our resilience to stress.

Want to learn more? I just launched a very cool education-based yoga project that talks about all this stress stuff and teaches practical tools to use to go further into understanding this topic and strengthening your PNS. Check it out!




Welltalks: Stress, anxiety and the Parasympathetic Yoga Project


Dr. Jessica Eastman is a Naturopathic Doctor at Klinik, an instructor at the Institute of Holistic Nutrition in Vancouver, BC, and the co-founder of the Parasympathetic Yoga Project. She works with young professionals, creatives, entrepreneurs, change makers and movement artists, and uses a combination of ancient wisdom and modern science to help people solve their complex health problems, and achieve optimal physical, mental and emotional wellbeing.