Chinese medicine has a long tradition of natural "ageless ageing", much of which centres o

n the use of the breath. This is something to which we give little attention in the West. It is strange to think that specific breathing techniques are ignored, given that the body's use of oxygen is the central determinant of the rate at which we age.

One of the reasons regular aerobic exercise is so beneficial in slowing the rate at which you age and at warding off degenerative diseases is that it improves your use of oxygen. So can learning to breathe fully. It can also improve your mood, increase your resistance to colds and illness, and improve your sleeping.

Full breathing is also an important tool for encouraging waste elimination—a kind of spring-cleaning process that can go on all year round, every day of your life.

Few people breathe fully. Most of us, particularly in sedentary jobs, breathe high—that is, we breathe quickly and in a shallow way, concentrating the inhalations in the upper chest area, which is the part of the lungs that holds the smallest quantity of air.

Not only does this kind of breathing inhibit oxygen intake, it can also encourage the lungs to atrophy and to lose their elasticity—a common occurrence as people get older.

Other people, who allow the air to flow deeper into their lungs, are mid-breathers. But to make the best use of oxygen for ageless ageing, it is important to develop the habit of taking total breaths so that they become a normal way of breathing.

In breathing totally, all of your breathing apparatus comes into play. The intercostal muscles expand the ribs outward to create a large space in which your lungs can inflate to their maximum. The diaphragm moves down, pulling the lower ribs outward, which lets even the very bottom of your lungs fill completely with air.

Practise it lying down for five minutes a couple of times a day—perhaps on awakening or just before going to sleep—and gradually it will become an automatic way of breathing. Not only will this help with ageless ageing, it will also help to improve your resistance to fatigue and the glow of your skin, It will also have some effect in protecting you from minor illness.

Here is the technique:

Lying flat on your back with a small pillow beneath your neck, place one hand on your abdomen and rest the other on one side of your ribcage, inhale slowly through your nose, imagining you are sending your breath to a place about two inches below your navel.

As the in-breath continues, let it fill your stomach. Then expand your ribcage to the side, as well as the mid-section of your chest. Now let the fresh breath fill the upper part of your chest area. The whole process of inhalation should take about five seconds.

Hold your breath for another five seconds to begin with, then gradually increase the time.

Now exhale, following the same gradual process: first, contract your lower abdomen gently, then let the lower lungs deflate, followed by the upper chest. This process should also take no more than five seconds to complete.

But note, it is important, before beginning the cycle again, to rest for a second or two.

With what topic is the passage primarily concerned'？

A．Ageless ageing.

B．The correct way of breathing.

C．The process of breathing.

D．Aerobic exercise.