Yoga is for everyone!
We have two hemispheres of the brain, both quite distinct and even though both are used in all the tasks we perform, they are used in different ways. For the Yogini, the relationship of the brain activity to their practice can be a valuable tool in cultivating a deeper, more enlightened practice. When you practice, observe which nostril is more open, and you will find that sometimes it is the left, sometimes it is the right, and sometimes both.
The left nostril correlates to the right side of the brain, so breathing through the left will send vibration to it, while the right nostril correlates to the left side of the brain. The left side of the brain is considered more logical and linear in its perception - it organizes the events of the past, categorizes everything, selects details that it deems important, then makes projections into the future so we can make "informed" decisions. The right side of the brain is in charge of visual, spacial, and representational. It perceives everything at once, a cacophony of sound, touch and sight. There is a great video on Youtube about the differences between the two sides of the brain that I highly recommend you watch next.
By becoming aware of this, we can channel Prana, the subtle energy, with a lot more purpose and awareness. The form of Prana that passes through the left nostril is called Ida, and the type of Prana that passes on the right is called Pingala. When these two types of Prana merge together into a central channel, it becomes Shushumna. These three currents of Prana correspond to Chitta (the Mind, the left nostril), life force (prana, the right nostril), and the spirit, atma (the central channel). We can influence the movement of Prana by controlling our breath. It is like playing with an alternating current.
You can become adept at manipulating Prana by practicing hand gestures, such as Hasta Mudras, or arm movements, such as Nyasam, or whole body positions by choosing which leg to fold over on top when settling down to meditate. We can stimulate the right nostril if we need to sort some things out in our lives, come up with a decision, or process some events of the past. We can stimulate the left nostril to enter the state of nirvana, or bliss, to experience our oneness with the world, to feel the flow of cosmic energy.
There is another great video on Youtube that I've always loved. A woman scientist who had been studying the brain one day has a stroke in her left hemisphere, and her account of what it was like to have that part of her brain shut down, while the right side of the brain took over - it is just amazing. Please watch!
In our Yoga practice, the left nostril breathing has a sedative, cooling, and calming effect, while the right nostril has an energizing, stimulating, and heating effect. The implication here is that we don't have to be a slave to our current mental state if we find it doesn't work for us. When you are agitated and hyper, notice if your left nostril is the congested one, and take a few breaths through it to open it up. Do left nostril breathing to calm yourself down before bed, or to enter that blissful state during meditation. When you feel lethargic and instead you need to have more energy, when you have hard physical work ahead of you, or are about to undertake purification practices, stimulate your right nostril.
For instructions on how to practice Nadi Shodhana, or Nadi Shuddhi, or Alternate Nostril Breath, watch my self-produced tutorial.
Very nice description .