There are four main ways to stimulate the flow of energy in the body: acupuncture, which relies upon needles inserted in special points along the meridians; acupressure, which again stimulates the tissues along the meridian lines (and, associated with this, are all the varieties of massage therapies and asana practices); simple awareness; and directed breathing.
Try this little experiment: look at your thumb, and imagine you can feel the energy inside of it. Notice how it begins to warm up, just by focusing there. Continue to focus, and feel the thumb for a full minute. The sensation of warmth is not imaginary.
When we bring our attention to a specific part of the body, our parasympathetic nervous system is engaged. When this happens, our heart rate slows down, and the blood vessels dilate, allowing more blood and energy to flood the area. We can feel this happening. Simple awareness brings energy to where we concentrate. This is the reason we want to pay attention, during our yoga practice, to what we are experiencing in the body. We want to be focused, not distracted by thoughts. We want to enhance the flow of energy through the tissues being exercised, by feeling what is happening there.
In addition to feeling a particular area of the body, we can also send our breath there. This may sound strange to anyone who has not done this: how can we breathe somewhere beyond our lungs? But remember, the whole body is interconnected. Take a deep inhalation right now, and notice how your shoulders and abdomen move. This is movement beyond the lungs. When the diaphragm descends, it presses against the stomach and liver. The stomach and liver in turn press onto the lower organs; they also press into the pit of the abdomen. Blood pressure and pulse rate rise on the inhalation and fall on the exhalation. This effect is felt all over the body.
The breath affects every cell in the body, directly or indirectly. Initially, this is something that just happens – it is outside our conscious control. As we practice directing the breath, we can begin to feel the effect of the breath. Later, we can actually increase or enhance this effect deliberately. It is easiest in areas closest to the lungs. Feel the lower abdomen on your next cycle of breath: notice the tension ebb and flow there. Then begin to notice, not just the tension, but the transfer of energy too. This combination of both attention, which alone brings energy to the area being focused on, along with moving the breath to the region, doubly increases the energy moving toward the area.
Now we are ready to combine this bare awareness with the breath, and guide our attention deeper. We are now able to direct our energy.