On a physical level, meditation stimulates activity in certain areas of the brain, and relaxes activity in other areas.
That is one way meditation works: by changing the activity level of the brain, it allows for easier flow of information from the memory banks, especially information which may be dismissed by the logical mind.
Since activity in certain areas of the brain is suppressed, meditation is an excellent way to manage pain. If you have chronic pain and use meditation for pain management, here’s how it works: brain activity in the insula and both sides of the anterior cingulate cortices increases (these determine the intensity of the pain the patient feels – increased activity in these areas correlates with decrease in perception of pain). Meditation also makes pain seem less unpleasant, by suppressing activity in the thalamus (which “shuts down” incoming sensory information) and activates the orbitofrontal cortex.
Meditation also stimulates activity in the parasympathetic nervous system. This is responsible for all of the “back office” functions of the body: digestion, cell repair, cell growth, immune response and other autonomic functions. So if you’re under a lot of stress, it manifests in the body (one way is through abdominal weight gain, as the body tries to shield the organs from toxins by encasing them in fat – toxins can be envirnomental and/or emotional!). By relaxing the sympathetic nervous system (“fight or flight”) the body can begin neutralizing the effects of stress.
None of this requires intense training – just practice.
Physical healing and pain management: during meditation, the parasympathetic nervous system is activated. The “rest, repair and digest” functions of the body become more active, and healing takes place. At the same time, you perception of pain is dulled and if you focus your mind intensely enough, you may lose all perception of pain!
Personal growth: learning to focus the mind brings immense relief from stress and anxiety. If you can deliberately focus your thoughts on what you want instead of what you don’t want, life becomes significantly more pleasant and your outlook becomes more optimistic, leading you to make more positive choices.
Okay – so brain activity increases in some areas and decreases in others. This is measured using EEG (electroencephalographic) monitoring. Studies have shown that both focused meditation (focusing on an object, mantra, etc.) and “loving-kindness” (compassion) meditation produce dramatic increases in activity in the frontal and parietal cortices. Other physical changes occur as well – the areas of the brain that become more active, also grow in physical size and increase in their “connectivity.”
This effect is permanent, and the longer you maintain a daily meditation practice, the greater the effect.
On a nonphysical level, meditation works by teaching you to focus your mind on one thing. Imagine if you were to focus exclusively on something you want to create, or on the solution to a problem you’re having. The key here is “solution” not “problem.” If you focus on the solution, the brain’s archives are opened up again. A memory might spark an idea. You also become aware of your surroundings and start noticing solutions. The interesting thing is that if you are focused on your problems (as you are when you allow the “monkey mind” to chatter away and you worry) – you will see problems all around you. You will see other people in the same situation, and you’ll gradually lose hope of finding a solution. But focus that amazing mind of yours on the solution, and… as answers come to you, you become empowered and you’re eager to take inspired action
.- See more at: http://www.omharmonics.com/blog/how-does-meditation-work/#sthash.nNsezCvv.dpuf