Writing this piece has been a roller coaster ride. I started this piece with just trying to compile different research papers around yoga and its health benefits, to learn more about how much of yoga's benefits is scientifically backed vs just "ancient knowledge".

The more I dug, the more I realised how much in depth I'd have to go into each topic. So i ended up splitting it into 2 parts - mental and physical. After doing this I realised, how much depth there is in each of these topics too, so for this piece, I've just taken the central nervous system and how yoga influences it - which in turn creates amazing mental health with very little effort.

Yoga for physical health is something people intuitively understand but there was a lot to uncover there in terms of balance and the benefits of balance for mental health. It's an interconnected web of bodily functions that all affect one another.

The more I read, the more I am impressed by the depth that went into the YogaSutras centuries ago, the first piece of text around Yoga.

One of the wonders of the world for me is the power of compounding. Personally, I consider Yoga knowledge and wisdom that has been compounded over 5 centuries. Very few other physical or mental exercise techniques can even claim that.

So in this piece I want to deconstruct the autonomous nervous system and how yoga influences it, which then leads to some amazing benefits mentally.

The properties of the autonomic nervous system are largely survival functions and have been evolving within us for 320 million years.

Our ancestors didn't live in cities, where they had access to food in restaurants or supermarkets, on the contrary they had to go hunting everyday where they had to face real dangers. Evolution in turn created systems for them to improve the probability of survival.

Though as civilizations evolved into more comfortable environments with very little survival risks, some of the systems that were built in during those days are still around

The autonomic nervous system (ANS) regulates our survival functions. We don't control our heart beat for example, and so many other core biological functions like breathing and digestion. It's called autonomic because most of it is automatic and doesn't require much conscious thought

The ANS contains of two complementary systems, called the sympathetic and parasympathetic nervous systems.

The sympathetic nervous system (SNS) operates when we move toward activity, for example when we get up in the morning, exercise or get stressed out. One of its daily jobs is to maintain the body's homeostatic functions by coordinating communication between the organs.

The parasympathetic nervous systems (PNS) operates on the other hand when we sleep, rest, digest or practice meditation / breathing exercises.

From an evolutionary perspective - when we sense danger - the sympathetic nervous systems kicks into a high gear state known as fight or flight. This initiates a domino effect around a bunch of hormones. These hormones have some serious short term benefits if a tiger is front of you, but not very good for mental health if it persists for longer.

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I wanted to share an excerpt from the book "One Simple Thing" by Eddie Stern, which has an interesting analogy for how these systems work.

"The sympathetic nervous system is like an accelerator in a car, and the parasympathetic nervous system, particularly its branches of the vagus nerve, is the brake. In fact, this mechanism is called the vagal brake. It is the vagal brake that restrains the activity of the sympathetic nerves and slows the heart rate down, as mentioned earlier, to between an average of 65 to 72 beats per minutes in a healthy adult

The alternation between accelerator and brake make the heart speed up and slow down with each breath; on the inhalation, the vagal brake releases enough to let the heart speed slightly, with the exhalation, the vagal break depresses and the heart slows.

The vagal brake, then, becomes an all-important moderator that slows down the fast-moving processes of the sympathetic nerves. Slower respiratory rates can strengthen the vagal brake and thus lead to a reduction of anxiety, stress, and inflammation - a process we will discuss later in the chapter.

According to biofeedback researcher and psychologist, Dr. Richard Gervitz, anger and anxiety throw off the vagal breaks. Kindness, appreciation, and gratitude strengthen it.