A friend of mine asked me this recently over coffee. His eyes gleamed with the excitement of having found a new way to unwind. “I’ve just taken up yoga and I have NEVER felt this relaxed. What is happening to me?!”

It’s a good question. Why *is* yoga so relaxing? This is what I told him.

‘FIGHT OR FLIGHT’

Normally we spend our days rushing around, stimulating our sympathetic nervous system at every turn. This is the body’s control system for managing our responses to stress and stimulation. It’s one of the two main divisions of the autonomic (involuntary) nervous system, which deals with all the functions we can’t consciously control. Its primary concern is our ‘fight or flight’ response.

AN ANTIDOTE TO CONSTANT STIMULATION

In our frantic modern world of constant notifications, multi-tasking and over-caffeination, many of us live in ‘fight or flight’ state most of the time. This drastically affects our biochemistry, and elevates blood levels of hormones like adrenaline and cortisol. Effects include increased heart rate, dilation of bronchial tubes and pupils, reduced saliva production, inhibited digestion, and greater conversion of glycogen to glucose. These hormones are great for danger-response and even short term stress management, but they can leave us feeling frazzled. Longer term, having an overactive sympathetic nervous system can lead to chronic fatigue syndrome, adrenal fatigue, cardiovascular problems, digestive problems, anxiety and depression, infertility, reduced sex drive and a lot of other health complications.

So. You go to yoga looking for some calm, and a healthy way to challenge your body. …And it works! But how? HOW does yoga make us feel so much calmer?

BREATH CONNECTS BODY AND MIND

Tuning into the breath invites a slowing down of the frantic movements of the mind to focus more singularly. This simple practice of awareness of breath is where yoga began, according to Patanjali’s two-thousand-year-old Yoga Sutras. These ancient texts describe meditation technique and ethical practices that long pre-date asana practice, or poses. The sutras do emphasise, however, that breath-awareness cultivates the yogic state of mind. You might say ‘but that’s all in my head, what about my body?’ But it’s important to understand that the psychological shift is vital in triggering profound physiological changes. These changes enable us to relax physically, at a deep nervous-system level.

THE PARASYMPATHETIC NERVOUS SYSTEM – ‘REST AND DIGEST’

Yoga’s focus on slower, deeper breathing stimulates the vagus nerve (the tenth cranial nerve) which is the longest nerve of the whole autonomic nervous system. It helps control the function of your heart, lungs and digestive tract, and yogic breathing can stimulate the vagus nerve sufficiently so as to ‘switch’ the body out of ‘fight or flight’ mode and into ‘rest and digest’ mode. This is a physiologically calmer state in which the body’s natural repair processes take place at a cellular and systemic level. The effects of activating the parasympathetic nervous system include the release of digestive enzymes for optimal digestion, increased saliva production, lowered heart rate, muscular relaxation, natural constriction of pupils in response to light, and increased urinary output (optimising waste removal). Regular cultivation of the ‘rest and digest’ state can alleviate most of the health problems associated with being in ‘fight or flight’ for too long.

BRINGING IT ALL TOGETHER

As the body moves into a more optimised physical state through the activity of the parasympathetic nervous system, the mind is also calmed, enabling a reduction in anxiety and psychological symptoms of stress. If we experience this first hand, we feel just how powerful the inter-relationship between mind and body is. At some level, humanity has known this for millennia: in countless places ancient wisdom agrees with modern research, despite the historically more binary approach taken by Western medicine. So whether you look to the vedic yoga texts, the ancient Roman adage, mens sana in copore sano (‘healthy mind in healthy body’), or cutting edge mind-body science – it is clear that the mind is part of the body. It makes sense then that choosing a practice that consciously unifies the two may well promote a deeper feeling of relaxation than belongs to activities which isolate mind or body.

In Sanskrit, yoga means ‘to yoke’, to bring together – to unify – and it is through unifying our minds and bodies, in both effort and ease as we move through our practice, that we are able to reach the deep relaxation or peace which the ancient yogis called samadhi – bliss.

By Camilla Walker