Why is Relaxation Good for Us?

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Many of us lead sedentary, yet stressful lives; and so in our spare time we feel the need to engage in physical exercise but find that classes such as spinning and aerobics can actually cause further undue stress. Of course, this is one of the reasons why yoga has become increasingly popular among City workers.

Stress is necessary for survival. It initiates the so-called “fight or flight response” – a colloquial term to describe the activation of the sympathetic nervous system. When this happens, adrenaline is released into the bloodstream (which in turn increases blood-flow and heightens alertness); more blood is diverted to the brain; the heart rate and breathing rate speed up, supplying the brain and muscles with sufficient oxygen and glucose; and the pupils dilate to improve vision. The body is therefore physically prepared to react to a perceived threat. Stress can also induce the release of oxytocin (which helps motivate social connection).

Conversely we have an equally important “rest and digest response” when the body is relaxed, and the parasympathetic nervous system is activated. The parasympathetic nervous system is necessary in order to repair and nourish the body. It is as essential for the body to take physical exercise as it is to relax; and in other words, a healthy balance needs to be maintained between the sympathetic and parasympathetic nervous systems. Heart rate variability (HRV) is a good way of detecting the balance between sympathetic and parasympathetic activity. HRV can be improved (ie. raised) by taking physical exercise combined with periods of “recovery” – or even better improved by practising yoga!

The nervous system is of course intrinsically interlinked with all the other systems of the body, such as the respiratory system and the circulatory system – and manipulation of any one system will accordingly have an effect on all the others. The easiest system to control is the respiratory, by altering our breathing; and thus pranayama in yoga may either trigger the sympathetic nervous system (for example during Bhastrika or “bellows breath”) or the parasympathetic nervous system (through deep and slow breathing, and by lengthening each exhalation). Similarly Hatha yoga can stimulate the sympathetic nervous system (through movement and/or by raising the arms above the head, and/or by positioning the heart above the head in inversions such as Downward-facing Dog). At other times, Hatha yoga will induce the parasympathetic nervous system (through static poses and/or by forward bends). By the end of an effective yoga class therefore, our nervous system should be ideally balanced. Both body and mind will ideally have been sufficiently challenged without being stressed, leaving us energised and yet at peace within.

On a psychological level yoga can help us fine-tune our attitude towards life, reaching acceptance and taking action as appropriate; engaging with situations and learning how to accept stress and put it to good use. When stressful situations are regarded in a positive light, the body may release the hormone DHEA (which is known to reduce levels of anxiety, depression, heart disease and neurodegeneration.) Therefore relaxation of body and mind really is extremely good for us!