In autumn the predominant element is metal 金 (jin). The two systems in the body that are most strongly activated at this time are the lungs and the large intestine. Both organs have the function of gathering in what is essential and of letting go of what is not needed. In the cycle of the five elements, metal is traditionally the first, as much as any circle can have a beginning or end.
After the growing and lengthening out of summer (the element of fire), and the centring and integration of late summer (the element of earth) it is now time to soften and draw our energy back in.
It is the best time to get back on track and to lay the foundations of our health over the next year. The way to do this is not to start running ten miles a day or to start dieting, as these are spring and summer activities. Rather, as the Nei Jing tells us, it is time to still our hearts and minds and to gather and collect the spirit and the qi 氣 (energy). This is the appropriate yin response to this yin season. Just as the trees are drawing in and letting go of their leaves, it is time for us to let go of what we have been carrying around all year which is no longer of any use to us.