Furthermore, we also find that by controlling the breath in various ways we actually gain control over immense amounts of energy! Most of the really difficult postures I've gotten into in yoga were entirely a result of conscious breathing, and not about my muscle strength.
The practice of pranayama can give us access to power, but it also increases our ability to focus. When your mind is scattered and you are trying to accomplish a hundred things at once, and it seems you can't get anything done at all, steady your breath. Suddenly, your brain mimics the regular pace of your lungs and diaphragm, and the thoughts are all still there, but have organized themselves into clear categories. You find you have the ability to put one task in front, and accomplish it from beginning to end with out distraction, and then onto the next, and so on.
Pranayama is a key to unlock our most powerful and most intelligent potential. After all, how are we able to function if our electricity is just spiraling out of control all over our mind and body? Control the breath, and you control the nerves which are the conductors of our lives. Each human is like a mini orchestra made up of many vibrations. With out a conscious conductor, we are just a mess of noise. With a conductor, the symphony roars in harmony and even improvises better on the spot. And so, if you want more control over your life, practice pranayama. Just 5 minutes a day of controlled breathing. It's harder then it sounds. The minute you sit to just practice breathing your brain starts freaking out, as if this is such a waste of time, and it has so many other things to do. But get passed that moment, and you'll be amazed at what you find!