Yoga is anciently known as a practice to achieve "cessation of the fluctuations of the mind". This doesn't automatically sound like something that has to do with twisting and breathing and balancing with a leg behind your ear, however it is truly a main goal, or rather beneficial side effect, of practicing any part of yoga. The main goal is probably different for every individual, since everyone comes to yoga with different hopes and expectations. The overall goal, I think, would be to let go of goals. Ultimately Samadhi or Bliss or Ecstasy is the "goal" but to reach this kind of state I believe takes a lot of letting go and we can learn to do this through yoga and through cessation of the fluctuations of the mind.
So what does that mean anyway? Anyone with a mind must know that it fluctuates constantly, or in other words races around non stop with a never ending stream of consciousness. Just think of those times when you're lying in bed about to go to sleep and you find yourself thinking about something. Then you get curious and you try to trace back your train of thought that lead you to think of that something. This is the fluctuating mind that is part of normal existence. Or you can use the image of brain waves that are undulating up and down during most waking states.
So does yoga really get us to cease and desist with this hyperactivity in our minds? And why do we need to do that anyway if it's so normal? Well of course our minds are amazing things and it's quite remarkable that we can take in so much information and store it and recall it and make abstract ideas with it. But what makes a mind truly remarkable is being well rounded. Our society and lifestyles encourage a multi-tasking, quick reacting, quick judging, surface scratching mind. Which is drowning out our natural ability to also do the opposite of that - focus on ONE thing, open up and let go of judging and take time to see beyond the surface. This may be a natural ability but one we're badly in need of practicing. Just like any other muscle if we don't use our concentration ability, we'll lose it.
By practicing something like yoga we are challenged to put our bodies into a position that is potentially difficult to maintain and then are told to stay and breathe. Instantly our mind has thoughts racing by such as: ooh my leg is gonna start shaking soon; I don't think I look like her when I do this position what am I doing wrong?; this doesn't really feel like anything for me; this is a waste of time; breathe? huff puff huff puff okay, hurry up let's get on with it....etc. etc. etc. Sounds pretty fluctuate-y right? So we add that all important breath as a tool to begin working on that brain. Okay you are in this pose that strengthens the legs and boosts the immune system and tones the core, but as you are doing all of that, can you focus on ONE thing - your breathing? Can you focus on it and control it? Can you choose to become the master of your breath and not let it run away with you? This act in itself has begun to tame those fluctuations. It has given your mind a task - use the sheer strength of your will to breathe slower and deeper when your body's habit is to breathe quick and fast and shallow. Of course there will still be more thoughts while you try to concentrate on breathing - I can't do it! I AM breathing, how much more can a person breathe? and so on :)
But that's why this is a practice. We won't be perfect. We won't get it right away. In fact we may feel as though we'll never get it, but the fact that we come back to practice again and again, time after time, shows that we are reaching a level of understanding.
Now that yoga has given us a way of learning to look past the up and down thoughts during a yoga pose, this can be applied to daily life. The next time you are in an uncomfortable position at work or in your personal life, see if you can feel yourself breathing. The split second it takes to step away from the situation and find your breath will be a moment that you are not spending getting caught up in your fluctuating mind as it reacts to the situation. It's an application of what is learned during mediation as well - meditation doesn't necessarily mean that the mind is cleared of all thoughts. It actually means that you are consciously stepping away from thoughts. They'll be there, racing around as usual, but you learn to let them race around without you. This ability, when actively practiced, will make you less quick to react to impulses. It will make you less likely to automatically act or think in a habitual way based on your particular upbringing and past experiences. What's wrong with reacting to impulses or thinking or acting according to your past experiences? It's not exactly wrong but it leaves out the possibility of being open to other options. Any time we act or think automatically it means we are not being mindful of our actions and thoughts. We are letting the fluctuations take us for a ride instead of being in the driver seat of our own life. When we step back from the up and downs, the impulses, we become present and fully conscious. From there we have a more objective and peaceful viewpoint. And wouldn't any mind like some more peace? So learn to create it for yourself. Do some yoga, or meditate, or just breathe. Practice being present.