October 4th 2020
It is sometimes said in jest that the definition of an adult is a person who has stopped growing vertically and started growing horizontally! In youth we defy gravity through the process of growing upwards and with our physical energy and activity. Then we reach a peak, turn the corner and begin to surrender to gravity….. eventually literally shrinking and sagging back down into the earth! The inverted postures are considered to be a way of slowing down the ageing effects of gravity, by temporarily reversing it, which is why they are often described as rejuvenating poses and recommended to be done every day. One of my students, who lived in South Korea, described discovering, in an area of a public park, set aside for various physical fitness practices, a slanted inversion apparatus. She was astonished to see people in their 80s, 90s and even one of 108, hanging upside down for up to an hour a day and to hear that most had been doing so for decades. Although, other factors, such as diet, almost certainly played a part in their remarkable sprightliness, the story is still quite a testament to the rejuvenating power of inversions. However, like most fabled elixirs of youth, inversions do not come without risks.
Sirsasana (headstand) and Sarvangasana (shoulderstand), known as the King and Queen of asanas, are amongst the most powerful of yoga poses in terms of their immediate and long term physiological, energetic and emotional effects and should be approached with respect and caution. They are also amongst the most contentious of yoga postures and the headstand, especially is one that most beginners to yoga aspire to – often before they are ready. Both require a high level of experience and awareness in order to achieve the correct alignment and avoid dangerous pressure on the head and neck. This is done mainly by correct ergonomic positioning, which requires flexibility and adequate strength of the supporting muscles and also by actively pressing downwards, so as to create what feels like an upward rebound effect from gravity. Thus, one gains maximum benefit while minimising the risk of injury. The main danger is that damage from poor practice, tends to be done gradually, over a period of time and without the practitioner being aware of it, until symptoms appear. This unfortunately is when the harm has already been done.
One of the most obvious effects of inversions is the reversal of the action of gravity on circulation. It is an age old recommendation to put ones’ feet up for the relief of general fatigue and also for aching, swelling, varicose veins and tiredness in the legs. Blood and lymph are thus more quickly drained from the legs towards the heart and it has an overall relaxing effect. Thus a small degree of inversion already gives marked benefits. With a greater degree of inversion, the increased venous return to the heart stimulates it to contract more strongly, thus exercising the cardiac muscle. Blood flow to the upper body is greatly increased. We experience this immediately and, for many people, it takes several months of gradually building up, both the time in the poses and the degree of inversion, for the body to be able to adjust and be comfortable in the fully inverted position. There are baroreceptors in the carotid arteries which are triggered by the stretch caused by increased blood flow. They bring about a reflex, short term lowering of the blood pressure. With progressive training, the body’s adaptation mechanisms are stimulated to respond more quickly, inversions become more comfortable and the longer term benefits increase. Inversions ultimately have a calming effect and thus good for alleviating stress, fatigue, anxiety, mild depression, insomnia and some types of headache.
Click on the image to see a short video of a sequence of 2 supported inversions, which can be done on your sofa or armchair at home.
While there is an obvious increase in blood flow to the head, it is a common belief, amongst yoga practitioners, that inverting the body increases blood flow to the brain. If this were true, most people, when inverting, would run some risk of a blood vessel bursting inside the brain, causing a stroke or, if a vessel ruptured in the eye, possible blindness. The body has, especially within delicate structures like the brain and the eyes, mechanisms for protecting itself, e.g the blood brain barrier. However, with chronic high blood pressure, the normal protective mechanisms do not work so well. This condition is also associated with hardening of the arteries, causing them to be more fragile, – much like an elastic band, which has been over-stretched too much for too long. High blood pressure is thus one of the main contra-indications for inverted poses. At the same time there is evidence that stimulating the blood pressure regulators, e.g. with exercise, helps to lower the resting blood pressure for longer periods of time. It may be possible that mild inversions and a slight increase in blood flow through the carotid arteries, could trigger lowering of blood pressure and be beneficial, with minimal risk. More controlled research is needed.
The simple fact of experiencing the world from an inverted perspective, visually and physiologically, can shift a mental or emotional blockage and help clear the mind. Many yoga techniques cause a rapid physiological and energetic change which alters body chemistry, mood and thoughts. Learning inversions also challenges many people to overcome a certain amount of fear and are thus very confidence building.
Many claims have been made and passed around in yoga classes, for the benefits of inversions, not all of which are as yet supported by actual, clinical evidence. At the same time, many dire warnings are issued about dangers, which are also not proven. If in doubt, it is of course, always advisable to remain on the side of caution, start low and only gradually build up to inverting more for longer periods, as the body adapts.