The human body is all about homeostasis. We like to be balanced, and when something is out of balance within the body it can show up in different ways, including fatigue, stress, various illnesses/disorders, etc.
Acupuncture can work to bring balance back to the body by stimulating the nervous system in such a way that chemicals are released from different areas of the body, like the brain, spinal cord, and muscles, which can correct pain and work on other chemicals within the body that can, in turn, “influence” the body’s own internal regulating system. Think of a garden, it needs water to grow, to be healthy, produce, and to live. The watering hose represents the meridians or channels within the body, through which energy should freely flow. If the hose is working properly then it can nourish the garden and the garden will flourish. If there is a kink in the hose or some type of obstruction, the water will not be able to flow properly through and the garden will not receive necessary nourishment and thus will wither. The same is true for the meridians of the body in which energy flows. The energy is like the water from the hose, the hose represents the channels, and the garden represents the tissue, organs, etc. If you kink or obstruct the channel the body is effected and knocked off balance.
Therefore, by using acupuncture, the needles work to stimulate the channels in order to help the energy flowing through the way it is suppose to. The acupuncture needles provide the stimulation necessary to un-kink the obstruction that is keeping the body from maintaining homeostasis.